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Encyclopedia > Mitochondrial DNA
Mitochondrial DNA (some captions in German)
Mitochondrial DNA (some captions in German)

Mitochondrial DNA (mtDNA) is the DNA located in organelles called mitochondria. Most other DNA present in eukaryotic organisms is found in the nucleus. Nuclear and mitochondrial DNA are thought to be of separate evolutionary origin, with the mtDNA being derived from the circular genomes of the bacteria that were engulfed by the early ancestors of today's eukaryotic cells. In the cells of current organisms, the vast majority of the proteins present in the mitochondria (numbering approximately 1500 different types in mammals) are coded for by nuclear DNA, but the genes for some of them, if not most, are thought to have originally been of bacterial origin, having since been transferred to the eukaryotic nucleus during evolution. In mammals, all mtDNA in a zygote is inherited solely from the mother, and this holds true for most other organisms as well. Image File history File links Size of this preview: 783 × 600 pixelsFull resolution (999 × 765 pixel, file size: 63 KB, MIME type: image/png) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links Size of this preview: 783 × 600 pixelsFull resolution (999 × 765 pixel, file size: 63 KB, MIME type: image/png) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... The structure of part of a DNA double helix Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions for the development and function of living organisms. ... Electron micrograph of a mitochondrion showing its mitochondrial matrix and membranes In cell biology, a mitochondrion (plural mitochondria) (from Greek μιτος or mitos, thread + χονδριον or khondrion, granule) is a membrane-enclosed organelle, found in most eukaryotic cells. ... Kingdoms Eukaryotes are organisms with complex cells, in which the genetic material is organized into membrane-bound nuclei. ... HeLa cells stained for DNA with the Blue Hoechst dye. ... This article is about evolution in biology. ... 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. ... Subclasses & Infraclasses Subclass †Allotheria* Subclass Prototheria Subclass Theria Infraclass †Trituberculata Infraclass Metatheria Infraclass Eutheria Mammals (class Mammalia) are warm-blooded, vertebrate animals characterized by the production of milk in female mammary glands and the presence of hair, three middle ear bones used in hearing, and a neocortex region in the... This article is about evolution in biology. ... It has been suggested that Biparental zygote be merged into this article or section. ...


Currently, human mtDNA is present at 100-10,000 separate copies per cell, with each circular molecule consisting of 16,569 base pairs with 37 genes, 13 proteins (polypeptides), 22 transfer RNA (tRNAs) and two ribosomal RNAs (rRNAs). In science, a molecule is a group of atoms in a definite arrangement held together by chemical bonds. ... Base pairs, of a DNA molecule. ... It has been suggested that Queuine be merged into this article or section. ... Ribosomal RNA (rRNA), a type of RNA synthesized in the nucleolus by RNA Pol I, is the central component of the ribosome, the protein manufacturing machinery of all living cells. ...

Contents

Use in identification

Unlike nuclear DNA, whose genes are rearranged in the process of recombination, there is usually no change in mtDNA from parent to offspring. Because of this, and the fact that the mutation rate of mtDNA is higher than that of nuclear DNA and is easily measured, mtDNA is a powerful tool for tracking matrilineage, and has been used in this role for tracking the ancestry of many species back hundreds of generations. Human mtDNA can also be used to identify individuals. Recombination usually refers to the biological process of genetic recombination and meiosis, a genetic event that occurs during the formation of sperm and egg cells. ... Matrilineality is a system in which one belongs to ones mothers lineage; it may also involve the inheritance of property or titles through the female line. ...


Origin of mitochondrial DNA

Endosymbiotic theory suggests that eukaryotic cells first appeared when a prokaryotic cell (a bacterium) was absorbed into another cell without being digested. These two cells are thought to have then entered into a symbiotic relationship forming the first organelle. This organelle would eventually become today's mitochondrion, and the genome of that first absorbed bacterium would have given rise to today's mitochondrial DNA as evolution progressed. The endosymbiotic theory concerns the origins of mitochondria and plastids (e. ... Kingdoms Eukaryotes are organisms with complex cells, in which the genetic material is organized into membrane-bound nuclei. ... Prokaryotes are unicellular (in rare cases, multicellular) organisms without a nucleus. ... Meat Ants harvest Leaf Hoppers for their honey dew. ... Schematic of typical animal cell, showing subcellular components. ...


Mitochondrial inheritance

Female inheritance

Mitochondria are normally inherited exclusively from the mother. The mitochondria in mammalian sperm are usually destroyed by the egg cell after fertilization.Also, most mitochondria are present at the base of the sperms tail, used for propelling the sperm cells, and this tail is lost during fertilization. In 1999 it was reported that paternal sperm mitochondria (containing mtDNA) are marked with ubiquitin to select them for later destruction inside the embryo.[1] Some in vitro fertilization techniques, particularly injecting a sperm into an oocyte, may interfere with this. Year 1999 (MCMXCIX) was a common year starting on Friday (link will display full 1999 Gregorian calendar). ... Ubiquitin is a very conserved small regulatory protein that is ubiquitous in eukaryotes. ... For other uses, see Embryo (disambiguation). ...


The fact that mitochondrial DNA is maternally inherited enables researchers to trace maternal lineage far back in time. (Y chromosomal DNA, paternally inherited, is used in an analogous way to trace the agnate lineage.) This is accomplished in humans by sequencing one or more of the hypervariable control regions (HVR1 or HVR2) of the mitochondrial DNA. HVR1 consists of about 440 base pairs. These 440 base pairs are then compared to the control regions of other individuals (either specific people or subjects in a database) to determine maternal lineage. Most often, the comparison is made to the revised. Vilà et al have published studies tracing the matrilineal descent of domestic dogs to wolves. The concept of the Mitochondrial Eve is based on the same type of analysis, attempting to discover the origin of humanity by tracking the lineage back in time. Matrilineality is a system in which one belongs to ones mothers lineage. ... The human Y chromosome is one of two sex chromosomes, it contains the genes that cause testis development, thus determining maleness. ... A hypervariable region (HVR) is a location within nuclear DNA or the D-loop of mitochondrial DNA in which base pairs of nucleotides repeat. ... Mitochondrial Eve (mt-mrca) is the name given by researchers to the woman who is the matrilineal most recent common ancestor (MRCA) for all living humans. ... Humanity refers to the human race or mankind as a whole, to that which is characteristically human, or to that which distinguishes human beings from other animals or from other animal species primal nature. ...


Because mtDNA is not highly conserved, and has a rapid mutation rate, it can be used in phylogenetic study. Biologists sequence a few selected genes across different species, and they can build an evolutionary tree depending on how conserved or divergent the sequences happen to be. A phylogeny (or phylogenesis) is the origin and evolution of a set of organisms, usually of a species. ...


Male inheritance

It has been reported that mitochondria can occasionally be inherited from the father [2] in some species such as mussels. Paternally inherited mitochondria have also been reported in some insects such as the fruit fly[2] and the honeybee.[3] In genetics, paternal mtDNA transmission and paternal mtDNA inheritance refer to the incidence of paternal mitochondrial DNA (mtDNA) being passed on to offspring. ...


Evidence supports rare instances of male mitochondrial inheritance in some mammals as well. Specifically, documented occurrences exist for mice,[4][5] where it was subsequently rejected. It has also been found in sheep,[6]and in cloned cattle. [7] It has been found in a single case in a, human, male and was linked to infertility[8]


While many of these cases involve cloned embryos or subsequent rejection of the paternal mitochondria, others document in vivo inheritance and persistence under lab conditions.


Genetic influence

Genetic illness

Mutations of mitochondrial DNA can lead to a number of illnesses including exercise intolerance and Kearns-Sayre syndrome (KSS), which causes a person to lose full function of their heart, eye, and muscle movements. (See also Mitochondrial disease). Exercise Intolerance is a medical term used to describe a condition where the patient who is unable to do physical exercise at the level that would be expected of someone in his or her general physical condition, or who experiences unusually severe post-exercise pain, fatigue, or other negative effects. ... Kearns-Sayre syndrome (abbreviated KSS) is a disease caused by a 5,000 base deletion in the mitochondrial DNA. As such, it is a rare genetic disease in that it can be heteroplasmic, that is, more than one genome can be in a cell at any given time. ... Mitochondrial diseases are a group of disorders relating to the mitochondria, the organelles that are the powerhouses of the eukaryotic cells that comprise higher-order lifeforms (including humans). ...


See also

Mitochondrial diseases are a group of disorders relating to the mitochondria, the organelles that are the powerhouses of the eukaryotic cells that comprise higher-order lifeforms (including humans). ... It has been suggested that Mitochondrial DNA be merged into this article or section. ... In genetics, paternal mtDNA transmission and paternal mtDNA inheritance refer to the incidence of paternal mitochondrial DNA (mtDNA) being passed on to offspring. ... In paleoanthropology, the single-origin hypothesis (or Out-of-Africa model) is one of two accounts of the origin of anatomically modern humans, Homo sapiens. ... Mitochondrial Eve (mt-mrca) is the name given by researchers to the woman who is the matrilineal most recent common ancestor (MRCA) for all living humans. ... The Cambridge Reference Sequence (CRS) for human mitochondrial DNA was first published in 1981 as a forerunner of the human genome project. ...

References

  1. ^ Sutovsky, P., et. al (Nov. 25, 1999). "Ubiquitin tag for sperm mitochondria". Nature 402: 371-372. DOI:10.1038/46466.  Discussed in [1].
  2. ^ Kondo R, Matsuura ET, Chigusa SI (1992). Further observation of paternal transmission of Drosophila mitochondrial DNA by PCR selective amplification method. Genet Res 59: 81-84.
  3. ^ Meusel MS, Moritz RF (1993). Transfer of paternal mitochondrial DNA during fertilization of honeybee (Apis mellifera L.) eggs. Curr Genet 24: 539-543.
  4. ^ Gyllensten U, Wharton D, Josefsson A (1991). Paternal inheritance of mitochondrial DNA in mice. Nature 352: 255-257.
  5. ^ Shitara H, Hayashi JI, Takahama S, Kaneda H, Yonekawa H (1998). Maternal inheritance of mouse mtDNA in interspecific hybrids: segregation of the leaked paternal mtDNA followed by the prevention of subsequent paternal leakage. Genetics 148: 851-857.
  6. ^ Zhao X, et al. (2004). Further evidence for paternal inheritance of mitochondrial DNA in the sheep (Ovis aries). Heredity 93:399-403.
  7. ^ Steinborn R, Zakhartchenko V, Jelyazkov J, Klein D, Wolf E, Muller M et al (1998). Composition of parental mitochondrial DNA in cloned bovine embryos. FEBS Lett 426: 352-356.
  8. ^ Schwartz M, Vissing J (2002). Paternal inheritance of mitochondrial DNA. N Engl J Med 22: 576-580.

Nature is one of the most prominent scientific journals, first published on 4 November 1869. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ...

External links

  • Mitomap - a human mitochondrial genome database [3]
  • A polymorphism in mitochondrial DNA associated with IQ?
  • mtDNA sequencing information
  • mtDNA and the global diaspora of modern humans Professor Stephen Oppenheimer's Genetic Map
  • Mitosearch (FTDNA)
  • EMPOP - Mitochondrial DNA Control Region Database


v  d  e
Major Families of Biochemicals
Peptides | Amino acids | Nucleic acids | Carbohydrates | Lipids | Terpenes | Carotenoids | Tetrapyrroles | Enzyme cofactors | Steroids | Flavonoids | Alkaloids | Polyketides | Glycosides
Analogues of nucleic acids: Types of Nucleic Acids Analogues of nucleic acids:
Nucleobases: Purine (Adenine, Guanine) | Pyrimidine (Uracil, Thymine, Cytosine)
Nucleosides: Adenosine/Deoxyadenosine | Guanosine/Deoxyguanosine | Uridine | Thymidine | Cytidine/Deoxycytidine
Nucleotides: monophosphates (AMP, UMP, GMP, CMP) | diphosphates (ADP, UDP, GDP, CDP) | triphosphates (ATP, UTP, GTP, CTP) | cyclic (cAMP, cGMP, cADPR)
Deoxynucleotides: monophosphates (dAMP, TMP, dGMP, dCMP) | diphosphates (dADP, TDP, dGDP, dCDP) | triphosphates (dATP, TTP, dGTP, dCTP)
Ribonucleic acids: RNA | mRNA | piRNA | tRNA | rRNA | ncRNA | sgRNA | shRNA | siRNA | snRNA | miRNA | snoRNA | LNA
Deoxyribonucleic acids: DNA | mtDNA | cDNA | plasmid | Cosmid | BAC | YAC | HAC
Analogues of nucleic acids: GNA | PNA | TNA | morpholino

  Results from FactBites:
 
Mitochondrial DNA - Genetics Home Reference (1399 words)
Mitochondrial genes are among the estimated 20,000 to 25,000 total genes in the human genome.
Mitochondrial DNA is prone to noninherited (somatic) mutations.
Mitochondrial DNA is typically diagrammed as a circular structure with genes and regulatory regions labeled.
Mitochondrial DNA - Wikipedia, the free encyclopedia (763 words)
Mitochondrial DNA (mtDNA) is DNA that is located in mitochondria.
The existence of mitochondrial DNA also supports the endosymbiotic theory, which suggests that eukaryotic cells first appeared when a prokaryotic cell was absorbed into another cell without being digested.
Mutations of mitochondrial DNA can lead to a number of illnesses including exercise intolerance and Kearns-Sayre syndrome (KSS), which causes a person to lose full function of their heart, eye, and muscle movements.
  More results at FactBites »

 
 

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