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Encyclopedia > Gene
This stylistic schematic diagram shows a gene in relation to the double helix structure of DNA and to a chromosome (right). Introns are regions often found in eukaryote genes which are removed in the splicing process (after the DNA is transcribed into RNA): only the exons encode the protein. This diagram labels a region of only 40 or so bases as a gene. In reality most genes are hundreds of times larger, and the relationships between Introns and exons can be highly complex.
This stylistic schematic diagram shows a gene in relation to the double helix structure of DNA and to a chromosome (right). Introns are regions often found in eukaryote genes which are removed in the splicing process (after the DNA is transcribed into RNA): only the exons encode the protein. This diagram labels a region of only 40 or so bases as a gene. In reality most genes are hundreds of times larger, and the relationships between Introns and exons can be highly complex.

A gene is a locatable region of genomic sequence, corresponding to a unit of inheritance, which is associated with regulatory regions, transcribed regions and/or other functional sequence regions.[1][2] The physical development and phenotype of organisms can be thought of as a product of genes interacting with each other and with the environment[3]. A concise definition of gene taking into account complex patterns of regulation and transcription, genic conservation and non-coding RNA genes, has been proposed by Gerstein et al.[4] "A gene is a union of genomic sequences encoding a coherent set of potentially overlapping functional products". In biology the genome of an organism is the whole hereditary information of an organism that is encoded in the DNA (or, for some viruses, RNA). ... This article or section does not adequately cite its references or sources. ... Views of a Foetus in the Womb, Leonardo da Vinci, ca. ... Individuals in the mollusk species Donax variabilis show diverse coloration and patterning in their phenotypes. ...


In cells, genes consist of a long strand of DNA that contains a promoter, which controls the activity of a gene, and a coding sequence, which determines what the gene produces. When a gene is active, the coding sequence is copied in a process called transcription, producing an RNA copy of the gene's information. This RNA can then direct the synthesis of proteins via the genetic code. However, RNAs can also be used directly, for example as part of the ribosome. These molecules resulting from gene expression, whether RNA or protein, are known as gene products. The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... A promoter is a regulatory region of DNA located upstream (towards the 5 region) of a gene, providing a control point for regulated gene transcription. ... A micrograph of ongoing gene transcription of ribosomal RNA illustrating the growing primary transcripts. ... For a non-technical introduction to the topic, see Introduction to Genetics. ... Figure 1: Ribosome structure indicating small subunit (A) and large subunit (B). ... Left: An RNA strand, with its nitrogenous bases. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... A gene product is the biochemical material, either RNA or protein, resulting from expression of a gene. ...


Genes often contain regions that do not encode products, but regulate gene expression. The genes of eukaryotic organisms can contain non-coding regions called introns that are removed from the messenger RNA in a process called splicing. The regions encoding gene products are called exons. In eukaryotes, a single gene can encode multiple proteins, which are produced through the creation of different arrangements of exons through alternative splicing. In prokaryotes (bacteria and archaea), introns are less common and genes often contain a single uninterrupted stretch of DNA, called a cistron, that codes for a product. Prokaryotic genes are often arranged in groups called operons with promoter and operator sequences that regulate transcription of a single long RNA. This RNA contains multiple coding sequences. Each coding sequence is preceded by a Shine-Dalgarno sequence that ribosomes recognize. Gene regulation is the general term for cellular control of protein synthesis at the DNA-RNA transcription step. ... Kingdoms Animalia - Animals Fungi Plantae - Plants Chromalveolata Protista Alternative phylogeny Unikonta Opisthokonta Metazoa Choanozoa Eumycota Amoebozoa Bikonta Apusozoa Cabozoa Rhizaria Excavata Corticata Archaeplastida Chromalveolata Animals, plants, fungi, and protists are eukaryotes (IPA: ), organisms whose cells are organized into complex structures by internal membranes and a cytoskeleton. ... Diagram of the location of introns and exons within a gene. ... In genetics, splicing is a modification of genetic information after transcription, in which introns of precursor messenger RNA (pre-mRNA) are removed and exons of it are joined. ... An exon is any region of DNA within a gene, that is transcribed to the final messenger RNA (mRNA) molecule, rather than being spliced out from the transcribed RNA molecule. ... Prokaryotic bacteria cell structure Prokaryotes (IPA: //) are a group of organisms that lack a cell nucleus (= karyon), or any other membrane-bound organelles. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... Phyla Crenarchaeota Euryarchaeota Korarchaeota Nanoarchaeota ARMAN The Archaea (), or archaebacteria, are a major group of microorganisms. ... An operon is a group of genes including an operator, a common promoter, and one or more structural genes that are controlled as a unit to produce messenger RNA (mRNA). ... A promoter is a regulatory region of DNA located upstream (towards the 5 region) of a gene, providing a control point for regulated gene transcription. ... In mathematics, an operator is a function that performs some sort of operation on a number, variable, or function. ... Look up Transcription in Wiktionary, the free dictionary. ... Left: An RNA strand, with its nitrogenous bases. ... The Shine-Dalgarno Sequence (AGGAGGU) is the signal for initiation of protein biosynthesis in bacterial mRNA. It is located 5 of the first coding AUG, and consists primarily, but not exclusively, of purines. ...


The total set of genes in an organism is known as its genome. An organism's genome size is generally lower in prokaryotes, both in number of base pairs and number of genes, than even single-celled eukaryotes. However, there is no clear relationship between genome sizes and complexity in eukaryotic organisms. One of the largest known genomes belongs to the single-celled amoeba Amoeba dubia, with over 670 billion base pairs, some 200 times larger than the human genome.[5] The estimated number of genes in the human genome has been repeatedly revised downward since the completion of the Human Genome Project; current estimates place the human genome at just under 3 billion base pairs and about 20,000–25,000 genes.[6]. A recent Science article gives a final number of 20,488, with perhaps 100 more yet to be discovered .[7] The gene density of a genome is a measure of the number of genes per million base pairs (called a megabase, Mb); prokaryotic genomes have much higher gene densities than eukaryotes. The gene density of the human genome is roughly 12–15 genes/Mb.[8] In biology the genome of an organism is the whole hereditary information of an organism that is encoded in the DNA (or, for some viruses, RNA). ... Genome size refers to the total amount of DNA contained within one copy of a genome. ... Prokaryotic bacteria cell structure Prokaryotes (IPA: //) are a group of organisms that lack a cell nucleus (= karyon), or any other membrane-bound organelles. ... Base pairs, of a DNA molecule. ... Kingdoms Animalia - Animals Fungi Plantae - Plants Chromalveolata Protista Alternative phylogeny Unikonta Opisthokonta Metazoa Choanozoa Eumycota Amoebozoa Bikonta Apusozoa Cabozoa Rhizaria Excavata Corticata Archaeplastida Chromalveolata Animals, plants, fungi, and protists are eukaryotes (IPA: ), organisms whose cells are organized into complex structures by internal membranes and a cytoskeleton. ... For other uses, see Amoeba (disambiguation). ... A graphical representation of the normal human karyotype. ... The Human Genome Projects (HGP) goal is to understand the genetic make-up of the human species by determining the DNA sequence of the human genome and the genome of a few model organisms. ... Science is the journal of the American Association for the Advancement of Science (AAAS). ...

Contents

History

Main article: History of genetics

The existence of genes was first suggested by Gregor Mendel (1822-1884), who, in the 1860s, studied inheritance in pea plants and hypothesized a factor that conveys traits from parent to offspring. He spent over 10 years of his life on one experiment. Although he did not use the term gene, he explained his results in terms of inherited characteristics. Mendel was also the first to hypothesize independent assortment, the distinction between dominant and recessive traits, the distinction between a heterozygote and homozygote, and the difference between what would later be described as genotype and phenotype. Mendel's concept was given a name by Hugo de Vries in 1889, who, at that time probably unaware of Mendel's work, in his book Intracellular Pangenesis coined the term "pangen" for "the smallest particle [representing] one hereditary characteristic"[9]. Wilhelm Johannsen abbreviated this term to "gene" ("gen" in Danish and German) two decades later. Gregor Mendel, the father of genetics The history of genetics is generally held to have started in 1865 when an Austrian monk, Gregor Mendel published his work on pea plants. ... “Mendel” redirects here. ... // The First Transcontinental Railroad in the USA was built in the six year period between 1863 and 1869. ... Binomial name L. Percentages are relative to US recommendations for adults. ... Look up Hypothesis in Wiktionary, the free dictionary. ... In genetics, Independent assortment is the process of random segregation and assortment of chromosomes during gametogenesis to produce genetically unique gametes. ... In genetics, the term dominant gene refers to the allele that causes a phenotype that is seen in a heterozygous genotype. ... In genetics, the term recessive gene refers to an allele that causes a phenotype (visible or detectable characteristic) that is only seen in a homozygous genotype (an organism that has two copies of the same allele). ... An organism is a heterozygote or heterozygous for a gene or trait if it has different alleles at the genes locus for each homologous chromosome. ... This article or section does not cite its references or sources. ... This article does not cite any references or sources. ... Individuals in the mollusk species Donax variabilis show diverse coloration and patterning in their phenotypes. ... Hugo Marie de Vries (16th February 1848-21st May 1935), a Dutch biologist, was one of three men - see also Carl Correns and Erich von Tschermak - who in 1900 rediscovered Gregor Mendels work on genetics. ... Wilhelm Ludvig Johannsen (February 3, 1857 - November 11, 1927) was a Danish botanist. ...


In the early 1900s, Mendel's work received renewed attention from scientists. In 1910, Thomas Hunt Morgan showed that genes reside on specific chromosomes. He later showed that genes occupy specific locations on the chromosome. With this knowledge, Morgan and his students began the first chromosomal map of the fruit fly Drosophila. In 1928, Frederick Griffith showed that genes could be transferred. In what is now known as Griffith's experiment, injections into a mouse of a deadly strain of bacteria that had been heat-killed transferred genetic information to a safe strain of the same bacteria, killing the mouse. Thomas Hunt Morgan (September 25, 1866 – December 4, 1945) was an American geneticist and embryologist. ... Figure 1: A representation of a condensed eukaryotic chromosome, as seen during cell division. ... Binomial name Meigen, 1830[1] Drosophila melanogaster (from the Greek for black-bellied dew-lover) is a two-winged insect that belongs to the Diptera, the order of the flies. ... Frederick Griffith (1879 - 1941) was a British medical officer. ... Griffiths experiment was conducted in 1928 by Frederick Griffith which was one of the first experiments suggesting that bacteria are capable of transferring genetic information, otherwise known as the “transforming principle”, which was later discovered to be DNA. Griffith used two strains of Pneumococcus (which infects mice), a S... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ...


In 1941, George Wells Beadle and Edward Lawrie Tatum showed that mutations in genes caused errors in certain steps in metabolic pathways. This showed that specific genes code for specific proteins, leading to the "one gene, one enzyme" hypothesis.[10] Oswald Avery, Collin Macleod, and Maclyn McCarty showed in 1944 that DNA holds the gene's information. In 1953, James D. Watson and Francis Crick demonstrated the molecular structure of DNA. Together, these discoveries established the central dogma of molecular biology, which states that proteins are translated from RNA which is transcribed from DNA. This dogma has since been shown to have exceptions, such as reverse transcription in retroviruses. Beadle won a Nobel Prize in 1958 George Wells Beadle (October 22, 1903 – June 9, 1989) was an American scientist in the field of genetics. ... Tatum won the Nobel Prize for his work in genetics Edward Lawrie Tatum (December 14, 1909 – November 5, 1975) was an American geneticist. ... In biochemistry, a metabolic pathway is a series of chemical reactions occurring within a cell. ... Oswald Theodore Avery (October 21, 1877–1955) was a Canadian-born American physician and medical researcher. ... Collin M. Macleod (1909-1972) was a geneticist. ... Maclyn McCarty (June 9, 1911–January 2, 2005) was an American geneticist. ... James Dewey Watson (born April 6, 1928) is an American molecular biologist, best known as one of the co-discoverers of the structure of DNA. Watson, Francis Crick, and Maurice Wilkins were awarded the 1962 Nobel Prize in Physiology or Medicine for their discoveries concerning the molecular structure of nucleic... Francis Harry Compton Crick OM FRS (8 June 1916 – 28 July 2004) was an English molecular biologist, physicist, and neuroscientist, who is most noted for being one of the co-discoverers of the structure of the DNA molecule in 1953. ... The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... Information flow in biological systems The central dogma of molecular biology was first enunciated by Francis Crick in 1958[1] and re-stated in a Nature paper published in 1970:[2] POSTLEWAITE IS A TOOL The central dogma of molecular biology deals with the detailed residue-by-residue transfer of... Left: An RNA strand, with its nitrogenous bases. ... Reverse transcriptase is an enzyme used by all retroviruses and retrotransposons that transcribes the genetic information from the virus or retrotransposon from RNA into DNA, which can integrate into the host genome. ... Genera Alpharetrovirus Betaretrovirus Gammaretrovirus Deltaretrovirus Epsilonretrovirus Lentivirus Spumavirus A retrovirus is any virus belonging to the viral family Retroviridae. ...


In 1972, Walter Fiers and his team at the Laboratory of Molecular Biology of the University of Ghent (Ghent, Belgium) were the first to determine the sequence of a gene: the gene for Bacteriophage MS2 coat protein.[11] Richard J. Roberts and Phillip Sharp discovered in 1977 that genes can be split into segments. This leads to the idea that one gene can make several proteins. Recently (as of 2003-2006), biological results let the notion of gene appear more slippery. In particular, genes do not seem to sit side by side on DNA like discrete beads. Instead, regions of the DNA producing distinct proteins may overlap, so that the idea emerges that "genes are one long continuum".[1] Year 1972 (MCMLXXII) was a leap year starting on Saturday (link will display full calendar) of the Gregorian calendar. ... Walter Fiers was born in Ieper (Belgium) in 1931. ... Ghent University (in Dutch, Universiteit Gent, abbreviated UGent) is one of the two large Flemish universities. ... This article is about the Belgian city. ... The bacteriophage MS2 or Bacillus phage M2 (Caudovirales, Podoviridae) infects Bacillus subtilis. ... Richard J. Roberts (b. ... Phillip Allen Sharp (born June 6, 1944), U.S. geneticist and molecular biologist; co-discovered gene splicing; shared the 1993 Nobel Prize in Physiology or Medicine with Richard J. Roberts for the discovery that genes in eukaryotes are not contiguous strings but contain introns, and that the splicing of messenger... Year 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... Biology studies the variety of life (clockwise from top-left) E. coli, tree fern, gazelle, Goliath beetle Biology (from Greek: βίος, bio, life; and λόγος, logos, knowledge), also referred to as the biological sciences, is the study of living organisms utilizing the scientific method. ... The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... Look up Region in Wiktionary, the free dictionary. ... Look up continuum in Wiktionary, the free dictionary. ...


Mendelian inheritance and classical genetics

Darwin used the term Gemmule to describe a microscopic unit of inheritance, and what would later become known as Chromosomes had been observed separating out during cell division by Wilhelm Hofmeister as early as 1848. The idea that chromosomes were the carriers of inheritance was expressed in 1883 by Wilhelm Roux. The modern conception of the gene originated with work by Gregor Mendel, a 19th century Augustinian monk who systematically studied heredity in pea plants. Mendel's work was the first to illustrate particulate inheritance, or the theory that inherited traits are passed from one generation to the next in discrete units that interact in well-defined ways. Danish botanist Wilhelm Johannsen coined the word "gene" in 1909 to describe these fundamental physical and functional units of heredity,[12] while the related word genetics was first used by William Bateson in 1905.[10] The word was derived from Hugo De Vries' 1889 term pangen for the same concept [9], itself a derivative of the word pangenesis coined by Darwin (1868).[13] The word pangenesis is made from the Greek words pan (a prefix meaning "whole", "encompassing") and genesis ("birth") or genos ("origin"). Mendelian inheritance (or Mendelian genetics or Mendelism) is a set of primary tenets relating to the transmission of hereditary characteristics from parent organisms to their children; it underlies much of genetics. ... Classical genetics consists of the techniques and methodologies of genetics that predate the advent of molecular biology. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Figure 1: A representation of a condensed eukaryotic chromosome, as seen during cell division. ... Wilhelm Friedrich Benedikt Hofmeister (18 May 1824 to 12 January 1877) was a German self-taught botanist. ... Wilhelm Roux (June 9, 1850–September 15, 1924) was a German zoologist and experimental embryologist. ... “Mendel” redirects here. ... Alternative meaning: Nineteenth Century (periodical) (18th century — 19th century — 20th century — more centuries) As a means of recording the passage of time, the 19th century was that century which lasted from 1801-1900 in the sense of the Gregorian calendar. ... The Augustinians, named after Saint Augustine of Hippo (died AD 430), are several Roman Catholic monastic orders and congregations of both men and women living according to a guide to religious life known as the Rule of Saint Augustine. ... Mendelian inheritance (or Mendelian genetics or Mendelism) is a set of primary tenets relating to the transmission of hereditary characteristics from parent organisms to their children; it underlies much of genetics. ... Botany is the scientific study of plant life. ... Wilhelm Ludvig Johannsen (February 3, 1857 - November 11, 1927) was a Danish botanist. ... This article is about the general scientific term. ... William Bateson. ... For other uses, see 1905 (disambiguation). ... Hugo Marie de Vries (16th February 1848-21st May 1935), a Dutch biologist, was one of three men - see also Carl Correns and Erich von Tschermak - who in 1900 rediscovered Gregor Mendels work on genetics. ... Pangenesis was Charles Darwins hypothetical mechanism for heredity. ... For other people of the same surname, and places and things named after Charles Darwin, see Darwin. ...


According to the theory of Mendelian inheritance, variations in phenotype - the observable physical and behavioral characteristics of an organism - are due to variations in genotype, or the organism's particular set of genes, each of which specifies a particular trait. Different genes for the same trait, which give rise to different phenotypes, are known as alleles. Organisms such as the pea plants Mendel worked on, along with many plants and animals, have two alleles for each trait, one inherited from each parent. Alleles may be dominant or recessive; dominant alleles give rise to their corresponding phenotypes when paired with any other allele for the same trait, while recessive alleles give rise to their corresponding phenotype only when paired with another copy of the same allele. For example, if the allele specifying tall stems in pea plants is dominant over the allele specifying short stems, then pea plants that inherit one tall allele from one parent and one short allele from the other parent will also have tall stems. Mendel's work found that alleles assort independently in the production of gametes, or germ cells, ensuring variation in the next generation. Individuals in the mollusk species Donax variabilis show diverse coloration and patterning in their phenotypes. ... This article does not cite any references or sources. ... For the hard rock band, see Allele (band). ... In genetics, the term dominant gene refers to the allele that causes a phenotype that is seen in a heterozygous genotype. ... It has been suggested that this article or section be merged into Dominance relationship. ... A gamete (from Ancient Greek γαμετης; translated gamete = wife, gametes = husband) is a cell that fuses with another gamete during fertilization (conception) in organisms that reproduce sexually. ... A germ cell is part of the germline and is involved in the reproduction of organisms. ...


Prior to Mendel's work, the dominant theory of heredity was one of blending inheritance, which proposes that the traits of the parents blend or mix in a smooth, continuous gradient in the offspring. Although Mendel's work was largely unrecognized after its first publication in 1866, it was rediscovered in 1900 by three European scientists, Hugo de Vries, Carl Correns, and Erich von Tschermak, who had reached similar conclusions from their own research. However, these scientists were not yet aware of the identity of the 'discrete units' on which genetic material resides. Gregor Johann Mendel In Darwins time, biologists held to the theory of blending inheritance -- an offspring was an average of its parents. ... Hugo Marie de Vries (16th February 1848-21st May 1935), a Dutch biologist, was one of three men - see also Carl Correns and Erich von Tschermak - who in 1900 rediscovered Gregor Mendels work on genetics. ... Carl Erich Correns (September 10, 1864, in Munich - February 14, 1933) was a German botanist and geneticist, who is notable primarily for his independent discovery of the principles of heredity, and for his rediscovery of Gregor Mendels earlier paper on that subject, which he achieved simultaneously but independent of... Erich Tschermak-Seysenegg Erich von Tschermak-Seysenegg (November 15, 1871 – October 11, 1962) was an Austrian agronomist. ...


A series of subsequent discoveries led to the realization decades later that chromosomes within cells are the carriers of genetic material, and that they are made of DNA (deoxyribonucleic acid), a polymeric molecule found in all cells on which the 'discrete units' of Mendelian inheritance are encoded. The modern study of genetics at the level of DNA is known as molecular genetics and the synthesis of molecular genetics with traditional Darwinian evolution is known as the modern evolutionary synthesis. Figure 1: A representation of a condensed eukaryotic chromosome, as seen during cell division. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the... The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... A polymer (from Greek: πολυ, polu, many; and μέρος, meros, part) is a substance composed of molecules with large molecular mass composed of repeating structural units, or monomers, connected by covalent chemical bonds. ... This article is about the general scientific term. ... Molecular genetics is the field of biology which studies the structure and function of genes at a molecular level. ... For other people of the same surname, and places and things named after Charles Darwin, see Darwin. ... This article is about evolution in biology. ... The modern evolutionary synthesis refers to a set of ideas from several biological specialities that were brought together to form a unified theory of evolution accepted by the great majority of working biologists. ...


Physical definitions

The chemical structure of a four-base fragment of a DNA double helix.
The chemical structure of a four-base fragment of a DNA double helix.

The vast majority of living organisms encode their genes in long strands of DNA. DNA consists of a chain made from four types of nucleotide subunits: adenosine, cytidine, guanosine, and thymidine. Each nucleotide subunit consists of three components: a phosphate group, a deoxyribose sugar ring, and a nucleobase. Thus, nucleotides in DNA or RNA are typically called 'bases'; consequently they are commonly referred to simply by their purine or pyrimidine original base components adenine, cytosine, guanine, thymine. Adenine and guanine are purines and cytosine and thymine are pyrimidines. The most common form of DNA in a cell is in a double helix structure, in which two individual DNA strands twist around each other in a right-handed spiral. In this structure, the base pairing rules specify that guanine pairs with cytosine and adenine pairs with thymine (each pair contains one purine and one pyrimidine). The base pairing between guanine and cytosine forms three hydrogen bonds, while the base pairing between adenine and thymine forms two hydrogen bonds. The two strands in a double helix must therefore be complementary, that is, their bases must align such that the adenines of one strand are paired with the thymines of the other strand, and so on. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... A nucleotide is a chemical compound that consists of a heterocyclic base, a sugar, and one or more phosphate groups. ... Adenosine is a nucleoside composed of adenine attached to a ribose (ribofuranose) moiety via a β-N9-glycosidic bond. ... Cytidine is a molecule (known as a nucleoside) that is formed when cytosine is attached to a ribose ring (also known as a ribofuranose) via a β-N1-glycosidic bond. ... The chemical structure of Guanosine Guanosine is a nucleoside comprising guanine attached to a ribose (ribofuranose) ring via a β-N9-glycosidic bond. ... The chemical structure of deoxythymidine Thymidine (more precisely called deoxythymidine can also be labelled deoxyribosylthymine, and thymine deoxyriboside) is a chemical compound, more precisely a pyrimidine deoxynucleoside. ... A phosphate, in inorganic chemistry, is a salt of phosphoric acid. ... Deoxyribose Deoxyribose, also known as D-Deoxyribose and 2-deoxyribose, is an aldopentose — a monosaccharide containing five carbon atoms, and including an aldehyde functional group. ... Adenine Guanine Thymine Cytosine ... Purine is a heterocyclic aromatic organic compound, consisting of a pyrimidine ring fused to an imidazole ring. ... Pyrimidine is a heterocyclic aromatic organic compound similar to benzene and pyridine, containing two nitrogen atoms at positions 1 and 3 of the six-member ring [1]. It is isomeric with two other forms of diazine. ... The Double-Helix are an alien race in the Wing Commander science fiction series. ... In genetics, two nucleotides on opposite complementary DNA or RNA strands that are connected via hydrogen bonds are called a base pair (often abbreviated bp). ... Guanine is one of the five main nucleobases found in the nucleic acids DNA and RNA; the others being adenine, cytosine, thymine, and uracil. ... Cytosine is one of the 5 main nucleobases used in storing and transporting genetic information within a cell in the nucleic acids DNA and RNA. It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached (an amine group at position 4 and a keto group at... For the programming language Adenine, see Adenine (programming language). ... For the similarly-spelled vitamin compound, see Thiamine Thymine, also known as 5-methyluracil, is a pyrimidine nucleobase. ...


Due to the chemical composition of the pentose residues of the bases, DNA strands have directionality. One end of a DNA polymer contains an exposed hydroxyl group on the deoxyribose, this is known as the 3' end of the molecule. The other end contains an exposed phosphate group, this is the 5' end. The directionality of DNA is vitally important to many cellular processes, since double helices are necessarily directional (a strand running 5'-3' pairs with a complementary strand running 3'-5') and processes such as DNA replication occur in only one direction. All nucleic acid synthesis in a cell occurs in the 5'-3' direction, because new monomers are added via a dehydration reaction that uses the exposed 3' hydroxyl as a nucleophile. // Hydroxyl group The term hydroxyl group is used to describe the functional group -OH when it is a substituent in an organic compound. ... Deoxyribose Deoxyribose, also known as D-Deoxyribose and 2-deoxyribose, is an aldopentose — a monosaccharide containing five carbon atoms, and including an aldehyde functional group. ... In molecular biology, the 5 end and the 3 end (pronounced 5-prime and 3-prime) are respectively the leading and tail ends of a strand of nucleic acid. ... A phosphate, in inorganic chemistry, is a salt of phosphoric acid. ... In molecular biology, the 5 end and the 3 end (pronounced 5-prime and 3-prime) are respectively the leading and tail ends of a strand of nucleic acid. ... DNA replication. ... Dehydration (hypohydration) is the removal of water (hydro in ancient Greek) from an object. ... In chemistry, a nucleophile (literally nucleus lover) is a reagent which is attracted to centres of positive charge. ...


The expression of genes encoded in DNA begins by transcribing the gene into RNA, a second type of nucleic acid that is very similar to DNA, but whose monomers contain the sugar ribose rather than deoxyribose. RNA also contains the base uracil in place of thymine. RNA molecules are less stable than DNA and are typically single-stranded. Genes that encode proteins are composed of a series of three-nucleotide sequences called codons, which serve as the "words" in the genetic "language". The genetic code specifies the correspondence during protein translation between codons and amino acids. The genetic code is nearly the same for all known organisms. Gene expression, or simply expression, is the process by which the inheritable information which comprises a gene, such as the DNA sequence, is made manifest as a physical and biologically functional gene product, such as protein or RNA. Several steps in the gene expression process may be modulated, including the... A micrograph of ongoing gene transcription of ribosomal RNA illustrating the growing primary transcripts. ... Left: An RNA strand, with its nitrogenous bases. ... Look up nucleic acid in Wiktionary, the free dictionary. ... Ribose Ribose, primarily seen as D-ribose, is an aldopentose — a monosaccharide containing five carbon atoms, and including an aldehyde functional group. ... Deoxyribose Deoxyribose, also known as D-Deoxyribose and 2-deoxyribose, is an aldopentose — a monosaccharide containing five carbon atoms, and including an aldehyde functional group. ... Uracil is a pyrimidine which is common and naturally occurring. ... For the similarly-spelled vitamin compound, see Thiamine Thymine, also known as 5-methyluracil, is a pyrimidine nucleobase. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... A nucleotide is a chemical compound that consists of a heterocyclic base, a sugar, and one or more phosphate groups. ... RNA codons. ... For a non-technical introduction to the topic, see Introduction to Genetics. ... Translation is the second process of protein biosynthesis (part of the overall process of gene expression). ... This article is about the class of chemicals. ...


RNA genes

In some cases, RNA is an intermediate product in the process of manufacturing proteins from genes. However, for other gene sequences, the RNA molecules are the actual functional products. For example, RNAs known as ribozymes are capable of enzymatic function, and miRNAs have a regulatory role. The DNA sequences from which such RNAs are transcribed are known as non-coding DNA, or RNA genes. Left: An RNA strand, with its nitrogenous bases. ... // A ribozyme (from ribonucleic acid enzyme, also called RNA enzyme or catalytic RNA) is an RNA molecule that catalyzes a chemical reaction. ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... The stem-loop secondary structure of a pre-microRNA from Brassica oleracea. ... The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... In genetics, noncoding DNA describes DNA which does not contain instructions for making proteins (or other cell products such as RNAs). ... A non-coding RNA (ncRNA) is any RNA molecule that functions without being translated into a protein. ...


Some viruses store their entire genomes in the form of RNA, and contain no DNA at all. Because they use RNA to store genes, their cellular hosts may synthesize their proteins as soon as they are infected and without the delay in waiting for transcription. On the other hand, RNA retroviruses, such as HIV, require the reverse transcription of their genome from RNA into DNA before their proteins can be synthesized. In 2006, French researchers came across a puzzling example of RNA-mediated inheritance in mouse. Mice with a loss-of-function mutation in the gene Kit have white tails. Offspring of these mutants can have white tails despite having only normal Kit genes. The research team traced this effect back to mutated Kit RNA.[14] While RNA is common as genetic storage material in viruses, in mammals in particular RNA inheritance has been observed very rarely. This article is about biological infectious particles. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the... An infection is the detrimental colonization of a host organism by a foreign species. ... Genera Alpharetrovirus Betaretrovirus Gammaretrovirus Deltaretrovirus Epsilonretrovirus Lentivirus Spumavirus A retrovirus is any virus belonging to the viral family Retroviridae. ... Species Human immunodeficiency virus 1 Human immunodeficiency virus 2 Human immunodeficiency virus (HIV) is a retrovirus that causes acquired immunodeficiency syndrome (AIDS, a condition in humans in which the immune system begins to fail, leading to life-threatening opportunistic infections). ... Reverse transcriptase is an enzyme used by all retroviruses and retrotransposons that transcribes the genetic information from the virus or retrotransposon from RNA into DNA, which can integrate into the host genome. ... In biology the genome of an organism is the whole hereditary information of an organism that is encoded in the DNA (or, for some viruses, RNA). ... For linguistic mutation, see Apophony. ...


Functional structure of a gene

All genes have regulatory regions in addition to regions that explicitly code for a protein or RNA product. A universal regulatory region shared by all genes is known as the promoter, which provides a position that is recognized by the transcription machinery when a gene is about to be transcribed and expressed. Although promoter regions have a consensus sequence that is the most common sequence at this position, some genes have "strong" promoters that bind the transcription machinery well, and others have "weak" promoters that bind poorly. These weak promoters usually permit a lower rate of transcription than the strong promoters, because the transcription machinery binds to them and initiates transcription less frequently. Other possible regulatory regions include enhancers, which can compensate for a weak promoter. Most regulatory regions are "upstream" — that is, before or toward the 5' end of the transcription initiation site. Eukaryotic promoter regions are much more complex and difficult to identify than prokaryotic promoters. A promoter is a regulatory region of DNA located upstream (towards the 5 region) of a gene, providing a control point for regulated gene transcription. ... In molecular biology and bioinformatics, a consensus sequence is a way of representing the results of a multiple sequence alignment, where related seqeunces are compared to each other, and similar functional sequence motifs are found. ... In genetics, an enhancer is a short region of DNA that can be bound with proteins (namely, the trans-acting factors, much like a set of transcription factors) to enhance transcription levels of genes (hence the name) in a gene-cluster. ... Kingdoms Eukaryotes are organisms with complex cells, in which the genetic material is organized into membrane-bound nuclei. ... A promoter is a regulatory region of DNA located upstream (towards the 5 region) of a gene, providing a control point for regulated gene transcription. ... Prokaryotes are unicellular (in rare cases, multicellular) organisms without a nucleus. ...


Many prokaryotic genes are organized into operons, or groups of genes whose products have related functions and which are transcribed as a unit. By contrast, eukaryotic genes are transcribed only one at a time, but may include long stretches of DNA called introns which are transcribed but never translated into protein (they are spliced out before translation). Splicing can also occur in prokaryotic genes, but is less common than in eukaryotes.[15] An operon is a group of key nucleotide sequences including an operator, a common promoter, and one or more structural genes that are controlled as a unit to produce messenger RNA (mRNA). ... Many genomes have been sequenced and their gene sequences are stored in general DNA sequence databases (e. ... Diagram of the location of introns and exons within a gene. ...


Chromosomes

The total complement of genes in an organism or cell is known as its genome, which may be stored on one or more chromosomes; the region of the chromosome at which a particular gene is located is called its locus. A chromosome consists of a single, very long DNA helix on which thousands of genes are encoded. Prokaryotes - bacteria and archaea - typically store their genomes on a single large, circular chromosome, sometimes supplemented by additional small circles of DNA called plasmids, which usually encode only a few genes and are easily transferable between individuals. For example, the genes for antibiotic resistance are usually encoded on bacterial plasmids and can be passed between individual cells, even those of different species, via horizontal gene transfer. Although some simple eukaryotes also possess plasmids with small numbers of genes, the majority of eukaryotic genes are stored on multiple linear chromosomes, which are packed within the nucleus in complex with storage proteins called histones. The manner in which DNA is stored on the histone, as well as chemical modifications of the histone itself, are regulatory mechanisms governing whether a particular region of DNA is accessible for gene expression. The ends of eukaryotic chromosomes are capped by long stretches of repetitive sequences called telomeres, which do not code for any gene product but are present to prevent degradation of coding and regulatory regions during DNA replication. The length of the telomeres tends to decrease each time the genome is replicated in preparation for cell division; the loss of telomeres has been proposed as an explanation for cellular senescence, or the loss of the ability to divide, and by extension for the aging process in organisms.[16] In biology the genome of an organism is the whole hereditary information of an organism that is encoded in the DNA (or, for some viruses, RNA). ... Figure 1: A representation of a condensed eukaryotic chromosome, as seen during cell division. ... Short and long arms Chromosome. ... Prokaryotic bacteria cell structure Prokaryotes (IPA: //) are a group of organisms that lack a cell nucleus (= karyon), or any other membrane-bound organelles. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... Phyla Crenarchaeota Euryarchaeota Korarchaeota Nanoarchaeota ARMAN The Archaea (), or archaebacteria, are a major group of microorganisms. ... Figure 1: Illustration of a bacterium with plasmids enclosed showing chromosomal DNA and plasmids. ... Antibiotic resistance is the ability of a microorganism to withstand the effects of an antibiotic. ... Horizontal gene transfer (HGT), also Lateral gene transfer (LGT), is any process in which an organism transfers genetic material to another cell that is not its offspring. ... HeLa cells stained for DNA with the Blue Hoechst dye. ... Schematic representation of the assembly of the core histones into the nucleosome. ... Gene expression, or simply expression, is the process by which the inheritable information which comprises a gene, such as the DNA sequence, is made manifest as a physical and biologically functional gene product, such as protein or RNA. Several steps in the gene expression process may be modulated, including the... A telomere is a region of highly repetitive DNA at the end of a linear chromosome that functions as a disposable buffer. ... DNA replication. ... In biology, senescence is the combination of processes of deterioration which follow the period of development of an organism. ... Ageing or aging is the process of getting older. ...


While the chromosomes of prokaryotes are relatively gene-dense, those of eukaryotes often contain so-called "junk DNA", or regions of DNA that serve no obvious function. Simple single-celled eukaryotes have relatively small amounts of such DNA, while the genomes of complex multicellular organisms, including humans, contain an absolute majority of DNA without an identified function.[6] However it now appears that, although protein-coding DNA makes up barely 2% of the human genome, about 80% of the bases in the genome may be being expressed, so the term "junk DNA" may be a misnomer.[2] Computational gene finding methods are still significantly more reliable than earlier techniques that required mapping the locations of specific mutations that gave rise to distinguishable alleles.[8] In molecular biology, junk DNA is a collective label for the portions of the DNA sequence of a chromosome or a genome for which no function has yet been identified. ...


In most eukaryotic species, very little of the DNA in the genome encodes proteins, and the genes may be separated by vast regions of non-coding DNA, much of which has been labeled "junk DNA" due to its apparent lack of function in the modern organism. A commonly studied type of "junk DNA" is the pseudogenes, or region of non-coding DNA that resembles expressed genes but usually lacks appropriate promoters and other control sequences; such regions are hypothesized to be the results of gene duplication events in a lineage's evolutionary past.[17] Moreover, the genes are often fragmented internally by non-coding sequences called introns, which can be many times longer than the coding sequence but are spliced during post-transcriptional modification of pre-mRNA. Kingdoms Animalia - Animals Fungi Plantae - Plants Chromalveolata Protista Alternative phylogeny Unikonta Opisthokonta Metazoa Choanozoa Eumycota Amoebozoa Bikonta Apusozoa Cabozoa Rhizaria Excavata Corticata Archaeplastida Chromalveolata Animals, plants, fungi, and protists are eukaryotes (IPA: ), organisms whose cells are organized into complex structures by internal membranes and a cytoskeleton. ... In genetics, noncoding DNA describes DNA which does not contain instructions for making proteins (or other cell products such as RNAs). ... In molecular biology, junk DNA is a collective label for the portions of the DNA sequence of a chromosome or a genome for which no function has yet been identified. ... A pseudogene is a nucleotide sequences that is similar to a normal gene, but is not expressed as a functional protein. ... Schematic of a region of a chromosome before and after a duplication event Gene duplication occurs when an error in homologous recombination, a retrotransposition event, or duplication of an entire chromosome leads to the duplication of a region of DNA containing a gene [1]. The significance of this process for... This article is about evolution in biology. ... Diagram of the location of introns and exons within a gene. ... In genetics, splicing is a modification of genetic information prior to translation. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... The interaction of mRNA in a eukaryote cell. ...


Genetic and genomic nomenclature

Gene nomenclature has been established by the HUGO Gene Nomenclature Committee (HGNC) for each known human gene in the form of an approved gene name and symbol (short-form abbreviation). All approved symbols are stored in the HGNC Database. Each symbol is unique and each gene is only given one approved gene symbol. It is necessary to provide a unique symbol for each gene so that people can talk about them. This also facilitates electronic data retrieval from publications. In preference each symbol maintains parallel construction in different members of a gene family and can be used in other species, especially the mouse. Gene nomenclature is the scientific naming of genes, the units of heredity in living organisms. ... Look up Hugo in Wiktionary, the free dictionary. ... This article does not cite any references or sources. ... This article is about the engineering discipline. ... For other uses, see Data (disambiguation). ... A gene family is a set of genes defined by presumed homology, i. ... For other uses, see Species (disambiguation). ... This article is about the animal. ...


Evolutionary concept of a gene

George C. Williams first explicitly advocated the gene-centric view of evolution in his 1966 book Adaptation and Natural Selection. He proposed an evolutionary concept of gene to be used when we are talking about natural selection favoring some genes. The definition is: "that which segregates and recombines with appreciable frequency." According to this definition, even an asexual genome could be considered a gene, insofar it have an appreciable permanency through many generations. George Williams Professor George Christopher Williams (b. ... The gene-centered view of evolution, gene selection theory or selfish gene theory holds that natural selection acts through differential survival of competing genes, increasing the frequency of those alleles whose phenotypic effects successfully promote their own propagation. ... Cover of the 1996 edition. ... For other uses, see Natural selection (disambiguation). ... This article is about the sexual orientation in humans. ...


The difference is: the molecular gene transcribes as a unit, and the evolutionary gene inherits as a unit.


Richard Dawkins' The Selfish Gene and The Extended Phenotype defended the idea that the gene is the only replicator in living systems. This means that only genes transmit their structure largely intact and are potentially immortal in the form of copies. So, genes should be the unit of selection. In The Selfish Gene Dawkins attempts to redefine the word 'gene' to mean "an inheritable unit" instead of the generally accepted definition of "a section of DNA coding for a particular protein". In River Out of Eden, Dawkins further refined the idea of gene-centric selection by describing life as a river of compatible genes flowing through geological time. Scoop up a bucket of genes from the river of genes, and we have an organism serving as temporary bodies or survival machines. A river of genes may fork into two branches representing two non-interbreeding species as a result of geographical separation. Clinton Richard Dawkins, FRS (born March 26, 1941) is a British ethologist, evolutionary biologist and popular science writer who holds the Charles Simonyi Chair for the Public Understanding of Science at the University of Oxford. ... Original book cover from the painting The Expectant Valley by zoologist Desmond Morris The Selfish Gene is a very popular and somewhat controversial book on evolutionary theory by Richard Dawkins, published in 1976. ... A cathedral termite mount – a small animal with a very noticeable extended phenotype The Extended Phenotype: The Long Reach of the Gene is a 1982 book by British ethologist Richard Dawkins. ... In a generic sense, a replicator can be anything capable of self-replication. ... This article does not cite any references or sources. ... Original book cover from the painting The Expectant Valley by zoologist Desmond Morris The Selfish Gene is a very popular and somewhat controversial book on evolutionary theory by Richard Dawkins, published in 1976. ... River out of Eden (subtitled A Darwinian View of Life) is a 1995 popular science book by Richard Dawkins. ... The table and timeline of geologic periods presented here is in accordance with the dates and nomenclature proposed by the International Commission on Stratigraphy. ... Life on Earth redirects here. ... Survival machine is a concept, first proposed by Richard Dawkins in The Selfish Gene, whereby all organisms should be considered as the protection genes construct to survive their surroundings in order to propagate. ... This article is about a biological term. ... For other uses, see Species (disambiguation). ...


The gene concept is still changing

The concept of the gene has changed considerably (see history section). Originally considered a "unit of inheritance" to a usually DNA-based unit that can exert its effects on the organism through RNA or protein products. It was also previously believed that one gene makes one protein; this concept has been overthrown by the discovery of alternative splicing and trans-splicing.[10] For other uses, see Gene (disambiguation). ... The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... Left: An RNA strand, with its nitrogenous bases. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Various modes of alternative splicing Alternative splicing is the process that occurs in eukaryotes in which the splicing process of a pre-mRNA transcribed from one gene can lead to different mature mRNA molecules and therefore to different proteins. ... Trans-splicing is a special form of RNA processing in eukaryotes where exons from two RNA molecules are ligated in an intermolecular reaction. ...


And the definition of gene is still changing. The first cases of RNA-based inheritance have been discovered in mammals.[14] In plants, cases of traits reappearing after several generations of absence have lead researchers to hypothesise RNA-directed overwriting of genomic DNA.[18] Evidence is also accumulating that the control regions of a gene do not necessarily have to be close to the coding sequence on the linear molecule or even on the same chromosome. Spilianakis and colleagues discovered that the promoter region of the interferon-gamma gene on chromosome 10 and the regulatory regions of the T(H)2 cytokine locus on chromosome 11 come into close proximity in the nucleus possibly to be jointly regulated.[19] Left: An RNA strand, with its nitrogenous bases. ... Biological inheritance is the process by which an offspring cell or organism acquires or becomes predisposed to characteristics of its parent cell or organism. ... In genetics, an enhancer is a short region of DNA that can be bound with proteins (namely, the trans-acting factors, much like a set of transcription factors) to enhance transcription levels of genes (hence the name) in a gene-cluster. ... The coding region of a gene is the portion of DNA that is transcribed into mRNA and translated into proteins. ... for disambiguation of the term promoter, see the promoter Wiktionary article In genetics, a promoter is a DNA sequence that enables a gene to be transcribed. ... Interferon-gamma or IFN-g is a dimerized soluble cytokine which is a Type II Interferon. ... Cytokines are a group of proteins and peptides that are used in organisms as signaling compounds. ... HeLa cells stained for DNA with the Blue Hoechst dye. ...


The concept that genes are clearly delimited is also being eroded. There is evidence for fused proteins stemming from two adjacent genes that can produce two separate protein products. While it is not clear whether these fusion proteins are functional, the phenomena is more frequent than previously thought.[20] Even more ground-breaking than the discovery of fused genes is the observation that some proteins can be composed of exons from far away regions and even different chromosomes.[21][2] This new data has led to an updated, and probably tentative, definition of a gene as "a union of genomic sequences encoding a coherent set of potentially overlapping functional products."[10] This new definition categorizes genes by functional products, whether they be proteins or RNA, rather than specific DNA loci; all regulatory elements of DNA are therefore classified as gene-associated regions.[10] The exon portion of a DNA strand encodes a specific portion of a protein. ...


See also

The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... Epigenetics is a term in biology used today to refer to features such as chromatin and DNA modifications that are stable over rounds of cell division but do not involve changes in the underlying DNA sequence of the organism. ... The gene-centered view of evolution, gene selection theory or selfish gene theory holds that natural selection acts through differential survival of competing genes, increasing the frequency of those alleles whose phenotypic effects successfully promote their own propagation. ... Gene expression, or simply expression, is the process by which the inheritable information which comprises a gene, such as the DNA sequence, is made manifest as a physical and biologically functional gene product, such as protein or RNA. Several steps in the gene expression process may be modulated, including the... A gene family is a set of genes defined by presumed homology, i. ... The gene pool of a species or a population is the complete set of unique alleles that would be found by inspecting the genetic material of every living member of that species or population. ... Gene therapy is the insertion of genes into an individuals cells and tissues to treat a disease, and hereditary diseases in which a defective mutant allele is replaced with a functional one. ... A genetic algorithm (or GA) is a search technique used in computing to find true or approximate solutions to optimization and search problems. ... Genetic programming (GP) is an evolutionary algorithm based methodology inspired by biological evolution to find computer programs that perform a user-defined task. ... A gene regulatory network (also called a GRN or genetic regulatory network) is a collection of DNA segments in a cell which interact with each other (indirectly through their RNA and protein expression products) and with other substances in the cell, thereby governing the rates at which genes in the... This article is about the general scientific term. ... In biology the genome of an organism is the whole hereditary information of an organism that is encoded in the DNA (or, for some viruses, RNA). ... Genomics is the study of an organisms entire genome; Rathore et al, . Investigation of single genes, their functions and roles is something very common in todays medical and biological research, and cannot be said to be genomics but rather the most typical feature of molecular biology. ... A homeobox is a DNA sequence found within genes that are involved in the regulation of development (morphogenesis) of animals, fungi and plants. ... The Human Genome Projects (HGP) goal is to understand the genetic make-up of the human species by determining the DNA sequence of the human genome and the genome of a few model organisms. ... This is a list of notable human genes or genetic variations. ... For other uses, see Meme (disambiguation). ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... A pseudogene is a nucleotide sequences that is similar to a normal gene, but is not expressed as a functional protein. ... Gene modulation redirects here. ... Left: An RNA strand, with its nitrogenous bases. ... A smart gene is an artificially constructed genetic molecule (known as a construct) composed of one or more genes encoding a protein to be expressed and a region (such as a promoter) that will only allow the protein to be expressed under specific conditions (such as the presence of a... Genetic pollution, genetic contamination or genetic swamping happens when original set of naturally evolved (wild) region specific genes / gene pool of wild animals and plants become hybridized with domesticated and feral varieties or with the genes of other nonnative wild species or subspecies from neighboring or far away regions. ... Wikipedia does not yet have an article with this exact name. ...

References

  1. ^ a b Pearson H (2006). "Genetics: what is a gene?". Nature 441 (7092): 398-401. PMID 16724031. 
  2. ^ a b c Elizabeth Pennisi (2007). "DNA Study Forces Rethink of What It Means to Be a Gene". Science 316 (5831): 1556-1557. 
  3. ^ see eg Martin Nowak's Evolutionary Dynamics
  4. ^ Gerstein MB, Bruce C, Rozowsky JS, Zheng D, Du J, Korbel JO, Emanuelsson O, Zhang ZD, Weissman S, Snyder M (2007). "What is a gene, post-ENCODE? History and updated definition". Genome Research 17 (6): 669-681. PMID 17567988. 
  5. ^ Cavalier-Smith T. (1985). Eukaryotic gene numbers, non-coding DNA, and genome size. In Cavalier-Smith T, ed. The Evolution of Genome Size Chichester: John Wiley.
  6. ^ a b International Human Genome Sequencing Consortium (2004). "Finishing the euchromatic sequence of the human genome.". Nature 431 (7011): 931-45. PMID 15496913. 
  7. ^ Pennisi, Elizabeth (2007). "Working the (Gene Count) Numbers_ Finally, a Firm Answer". Science 316 (5828): 1113. 
  8. ^ a b Watson JD, Baker TA, Bell SP, Gann A, Levine M, Losick R (2004). Molecular Biology of the Gene, 5th ed., Peason Benjamin Cummings (Cold Spring Harbor Laboratory Press). ISBN 080534635X. 
  9. ^ a b Vries, H. de (1889) Intracellular Pangenesis [1] ("pangen" definition on page 7 and 40 of this 1910 translation in English)
  10. ^ a b c d e Mark B. Gerstein et al., "What is a gene, post-ENCODE? History and updated definition," Genome Research 17(6) (2007): 669-681
  11. ^ Min Jou W, Haegeman G, Ysebaert M, Fiers W (1972). "Nucleotide sequence of the gene coding for the bacteriophage MS2 coat protein". Nature 237 (5350): 82-8. PMID 4555447. 
  12. ^ The Human Genome Project Timeline. Retrieved on 2006-09-13.
  13. ^ Darwin C. (1868). Animals and Plants under Domestication (1868).
  14. ^ a b Rassoulzadegan M, Grandjean V, Gounon P, Vincent S, Gillot I, Cuzin F (2006). "RNA-mediated non-mendelian inheritance of an epigenetic change in the mouse". Nature 441 (7092): 469-74. PMID 16724059. 
  15. ^ Woodson SA (1998). "Ironing out the kinks: splicing and translation in bacteria". Genes Dev. 12 (9): 1243–7. PMID 9573040. 
  16. ^ Braig M, Schmitt C (2006). "Oncogene-induced senescence: putting the brakes on tumor development". Cancer Res 66 (6): 2881-4. PMID 16540631. 
  17. ^ Lodish, H, Berk A, Matsudaira P, Kaiser CA, Krieger M, Scott MP, Zipursky SL, Darnell J. (2004). Molecular Cell Biology, 5th, New York: WH Freeman.
  18. ^ Lolle & colleagues (2005) Genome-wide non-mendelian inheritance of extra-genomic information in Arabidopsis. PMID 15785770
  19. ^ Spilianakis & colleagues (2005) Interchromosomal associations between alternatively expressed loci. PMID 15880101
  20. ^ Parra & colleagues (2006) Tandem chimerism as a means to increase protein complexity in the human genome. PMID 16344564
  21. ^ Kapranov & colleagues (2005) Examples of the complex architecture of the human transcriptome revealed by RACE and high-density tiling arrays. PMID 15998911

A German eye doctor and amateur mathematician, Dr. Martin Nowak of Michelfeld, Germany discovered the worlds largest prime number after a 50-day search using his personal computer. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 256th day of the year (257th in leap years) in the Gregorian calendar. ... For other uses, see Race (disambiguation). ...

Further reading

Clinton Richard Dawkins, FRS (born March 26, 1941) is a British ethologist, evolutionary biologist and popular science writer who holds the Charles Simonyi Chair for the Public Understanding of Science at the University of Oxford. ... Original book cover from the painting The Expectant Valley by zoologist Desmond Morris The Selfish Gene is a very popular and somewhat controversial book on evolutionary theory by Richard Dawkins, published in 1976. ... Clinton Richard Dawkins, FRS (born March 26, 1941) is a British ethologist, evolutionary biologist and popular science writer who holds the Charles Simonyi Chair for the Public Understanding of Science at the University of Oxford. ... River out of Eden (subtitled A Darwinian View of Life) is a 1995 popular science book by Richard Dawkins. ...

External links

Wikibooks
Wikibooks has a book on the topic of

Image File history File links Wikibooks-logo-en. ... Wikibooks logo Wikibooks, previously called Wikimedia Free Textbook Project and Wikimedia-Textbooks, is a wiki for the creation of books. ... Gene. ... Image File history File links Sound-icon. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 111th day of the year (112th in leap years) in the Gregorian calendar. ... Image File history File links Sound-icon. ...

Tutorial and news

New Scientist is a weekly international science magazine covering recent developments in science and technology for a general English-speaking audience. ...

References and databases


  Results from FactBites:
 
Gene Macintosh Genealogy Software (264 words)
Gene is a shareware genealogy database for the Macintosh written by David and Diana Eppstein.
Gene is capable of handling complicated databases with thousands of names, multiple marriages and divorces, adoptions, illegitimate children, and intermarriage between relatives.
In the meantime, Gene still runs well under the Classic environment of OS X, but Gene and BibGene are the only classic programs I still use regularly so I am quite interested in getting them updated.
  More results at FactBites »

 
 

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