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Encyclopedia > Most recent common ancestor

The most recent common ancestor (MRCA) of any set of organisms is the most recent individual from which all organisms in the group are directly descended. The term is most frequently used of humans. The equivalent term concestor was coined by the biologist Richard Dawkins. A crab is an example of an organism. ... Clinton Richard Dawkins (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 Oxford University. ...


The MRCA of a set of individuals can sometimes be determined by referring to an established pedigree. In general, however, it is impossible to identify the specific MRCA of a set of individuals, but an estimate of the time at which the MRCA lived can often be given; such estimates can be given based on DNA test results and established mutation rates, or by reference to a non-genetic genealogical model.

Contents

MRCA of two individuals

The most recent common patrilineal ancestor of any two males, and the most recent common matrilineal ancestor of any two individuals can be determined by genealogical DNA tests. The tests use mitochondrial DNA for matrilineal inheritance or Y-chromosome-DNA for patrilineal inheritance. // A genealogical DNA test involves examining the nucleotides at specific locations on a persons DNA. The tests results are meant to have no informative medical value and do not determine specific genetic diseases or disorders (see possible exceptions in Medical information below); they are intended only for use in... // Mitochondrial DNA (mtDNA) is DNA that is located in mitochondria. ... This article or section does not cite its references or sources. ...


MRCA of all living humans

The existence of an MRCA does not imply any sort of population bottleneck or first couple. The MRCA of everyone alive today could have co-existed with a large human population, most of whom either have no living descendants today or else are ancestors of almost everyone alive today. A population bottleneck (or genetic bottleneck) is an evolutionary event in which a significant percentage of a population or species is killed or otherwise prevented from reproducing, and the population is reduced by 50% or more, often by several orders of magnitude. ... Creation according to Genesis refers to the description of the creation of the heavens and the earth by God, as described in Genesis, the first book of the Bible. ...


Patrilineal and matrilineal ancestry

The most recent common patrilineal ancestor of all living male humans, known as Y-chromosomal Adam, and the most recent common matrilineal ancestor of all living humans, known as Mitochondrial Eve, have been established by researchers using tests of the same kinds of DNA as for two individuals.[1] Mitochondrial Eve is estimated to have lived about 150,000 years ago. Y-chromosomal Adam is estimated to have lived between 60,000 and 90,000 years ago. The MRCA of humans alive today necessarily lived more recently than either. Patrilineality (a. ... In human genetics, Y-chromosomal Adam (Y-mrca) is the male counterpart to mitochondrial Eve: the most recent common ancestor from whom all male human Y chromosomes are descended. ... Matrilineality is a system in which one belongs to ones mothers lineage. ... Mitochondrial Eve (mt-mrca) is the name given by researchers to the woman who is the matrilineal most recent common ancestor for all living humans, from whom all mitochondrial DNA (mtDNA) in living humans is derived. ... // A genealogical DNA test involves examining the nucleotides at specific locations on a persons DNA. The tests results are meant to have no informative medical value and do not determine specific genetic diseases or disorders (see possible exceptions in Medical information below); they are intended only for use in...


Time estimates

Depending on the survival of isolated lineages without admixture from Modern migrations and taking into account long-isolated peoples, such as historical tribes in central Africa, Australia and remote islands in the South Pacific, the human MRCA is generally assumed to have lived in the Paleolithic period. mtDNA-based chart of large human migrations. ... The Paleolithic or Palaeolithic (Greek παλαιός paleos=old and λίθος lithos=stone or the Old Stone Age) was the first period in the development of human technology of the Stone Age. ...


However, Rohde, Olson, and Chang (2004), using a non-genetic model, estimated that the MRCA of all living humans may have lived within historical times (3rd millennium BC to 1st millennium AD). Rhode (2005) refined the simulation with parameters from estimated historical human migrations and of population densities. For conservative parameters, he pushes back the date for the MRCA to the 6th millennium BC (p. 20), but still concludes with a "surprisingly recent" estimate of a MRCA living in the second or first millennium BC (p. 27). An explanation of this result is that, while humanity's MRCA was indeed a Paleolithic individual up to Early Modern times, the European explorers of the 16th and 17th centuries would have fathered enough offspring so that some "mainland" ancestry by today pervades even remote habitats. The possibility remains, however, that a single isolated population with no recent "mainland" admixture persists somewhere, which would immediately push back the date of humanity's MRCA by many millennia. While simulations help estimate probabilities, the question can be resolved authoritatively only by genetically testing every living human individual. The 3rd millennium BC spans the Early to Middle Bronze Age. ... (Redirected from 1st millennium AD) (1st millennium BC – 1st millennium – 2nd millennium – other millennia) Events Beginning of Christianity and Islam London founded by Romans as Londinium Diaspora of the Jews The Olympic Games observed until 393 The Library of Alexandria, largest library in the world, burned Rise... Human migration denotes any movement of groups of people from one locality to another. ... During the 6th millennium BC, agriculture spreads from the Balkans to Italy and Eastern Europe and from Mesopotamia to Egypt. ... The early modern period is a term used by historians to refer to the period in Western Europe and its first colonies, between the Middle Ages and modern society. ... (15th century - 16th century - 17th century - more centuries) As a means of recording the passage of time, the 16th century was that century which lasted from 1501 to 1600. ... (16th century - 17th century - 18th century - more centuries) As a means of recording the passage of time, the 17th century was that century which lasted from 1601-1700. ...


Other models reported in Rohde, Olson, and Chang (2004) suggest that the MRCA of Western Europeans lived as recently as AD 1000. The same article provides surprisingly recent estimates for the identical ancestors point, the most recent time when each person then living was either an ancestor of all the persons alive today or an ancestor of none of them. The estimates for this are similarly uncertain, but date to considerably earlier than the MRCA, according to Rohde (2005) roughly to between 15,000 and 5,000 years ago. A common understanding of Western Europe in modern times. ...


MRCA of different species

It is also possible to use the term MRCA to describe the common ancestor of two or more different species. This concept is described in Richard Dawkins' book, The Ancestor's Tale, in which he imagines a backwards 'pilgrimage' in time, during which we humans 'meet' all the other species of organism with which we share a common ancestor. Dawkins coined the word, concestor, as an alternative to MRCA. Last universal ancestor (LUA), the hypothetical latest living organism from which all currently living organisms descend. ... Clinton Richard Dawkins (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 Oxford University. ... The Ancestors Tale cover The Ancestors Tale (subtitled A Pilgrimage to the Dawn of Life) is a 2004 popular science book by Richard Dawkins, with contributions from Dawkins research assistant Yan Wong. ... This article is about modern humans. ... A crab is an example of an organism. ...


Following the human evolutionary tree backwards, we first meet the concestor which we share with the species that are our closest relatives, the chimpanzee and bonobo. Dawkins estimates this to have occurred between 5 and 7 million years ago. Another way of looking at this is to say that our (approximately) 250,000-greats-grandparent was a creature from which all humans, chimpanzees and bonobos are directly descended. This article does not cite its references or sources. ... Type species Simia troglodytes Blumenbach, 1775 distribution of Species Pan troglodytes Pan paniscus Chimpanzee, often shortened to chimp, is the common name for the two extant species in the genus Pan. ... Binomial name Pan paniscus Schwarz, 1929 Bonobo distribution The Bonobo (Pan paniscus), until recently usually called the Pygmy Chimpanzee and less often the Dwarf or Gracile Chimpanzee, is one of the two species comprising the chimpanzee genus, Pan. ...


Further on in Dawkins' imaginary journey, we meet the concestor we share with the Gorilla, our next nearest relative, then the Orangutan, and so on. The MRCA for all living organisms is also known as the last universal ancestor. Type species Troglodytes gorilla Savage, 1847 distribution of Gorilla Species Gorilla gorilla Gorilla beringei The gorilla, the largest of the living primates, is a ground-dwelling herbivore that inhabits the forests of Africa. ... Type Species Simia pygmaeus Linnaeus, 1760 Orangutan distribution Species Pongo pygmaeus Pongo abelii The orangutans are two species of great apes with long arms and reddish, sometimes brown, hair native to Indonesia and Malaysia . ... Last universal ancestor (LUA), the hypothetical latest living organism from which all currently living organisms descend. ...


References

  1. ^ Notions such as Mitochondrial Eve and Y-chromosomal Adam yield common ancestors that are more ancient than for all living humans (Hartwell 2004:539).
  • Chang JT (1999) "Recent common ancestors of all present-day individuals". Advances in Applied Probability 31: 1002-1026.
  • Dawkins, R (2004) The Ancestor's Tale, A Pilgrimage to the Dawn of Life. Weidenfeld & Nicolson. ISBN 0-7528-7321-0
  • Hartwell L, Hutchison F, Hood L, Goldberg ML, Reynolds AE, Silver LM, Veres R (2004) Genetics: From Genes to Genomes. McGraw-Hill.
  • Rohde DLT, Olson S, Chang JT (2004) "Modelling the recent common ancestry of all living humans". Nature 431: 562-566.
  • Rohde, DLT , On the common ancestors of all living humans. Submitted to American Journal of Physical Anthropology. (2005)

Mitochondrial Eve (mt-mrca) is the name given by researchers to the woman who is the matrilineal most recent common ancestor for all living humans, from whom all mitochondrial DNA (mtDNA) in living humans is derived. ... In human genetics, Y-chromosomal Adam (Y-mrca) is the male counterpart to mitochondrial Eve: the most recent common ancestor from whom all male human Y chromosomes are descended. ... Clinton Richard Dawkins (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 Oxford University. ... The Ancestors Tale cover The Ancestors Tale (subtitled A Pilgrimage to the Dawn of Life) is a 2004 popular science book by Richard Dawkins, with contributions from Dawkins research assistant Yan Wong. ...

See also

// A genealogical DNA test involves examining the nucleotides at specific locations on a persons DNA. The tests results are meant to have no informative medical value and do not determine specific genetic diseases or disorders (see possible exceptions in Medical information below); they are intended only for use in... Genealogy is the study and tracing of family pedigrees. ... Genetic genealogy is the application of genetics to traditional genealogy. ... Last universal ancestor (LUA), the hypothetical latest living organism from which all currently living organisms descend. ... Genetic distance is a measure of the disimilarity of genetic material between different species or individuals of the same species. ...

External links

  • DNA Heritage - Understanding MRCA for genetic genealogy
  • Family Tree DNA - Understanding MRCA
  • "Modelling the Most Recent Common Ancestry of All Living Humans"
  • Paper on estimating MRCA from Y-chromosomal or mt-DNA data
  • link to a downloadable MRCA calculator (".exe" file)
  • identical ancestors point - explaining the relationship of "most recent common ancestor" and "identical ancestors point"
  • "On the Common Ancestors of All Living Humans"
  • "Human populations are tightly interwoven"
  • "Most Recent Common Ancestor of All Living Humans Surprisingly Recent"
  • AP: Roots of human family tree are shallow
  • LostCousins - project linking people who share the same ancestors

  Results from FactBites:
 
Common ancestor - EvoWiki (281 words)
Identifying common ancestors is one of the tasks you have to do when systematically ordering known species.
Usually it is these recent common ancestors that biologists/paleontologists are concerned with, and the most recent link between later species would be the last common ancestor (LCA) while the LCA of all contemporary life on Earth is known as the Last Universal Common Ancestor (LUCA).
A fossil of the common ancestor or a related form is a transitional fossil.
Common descent - Wikipedia, the free encyclopedia (802 words)
The most recent common ancestor is the most recent population or species which is an ancestor of all of the species being referenced, whether that be polar bears and sun bears or woolly mammoths and African elephants or even all four of those species which ancestor would most likely be one of the earliest mammal.
The broadest form of common descent is universal common descent, which is the theory that all life on earth originated from one the same common ancestor billions of years ago.
Common vegetables such as cabbage, kale, broccoli, cauliflower, kohlrabi and Brussels sprouts are all decedents of the wild mustard plant.
  More results at FactBites »

 
 

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