Mitochondrial Eve

{{Short description|Matrilineal most recent common ancestor of all living humans}}

{{Infobox haplogroup

|map=Early_diversification.PNG

|name=L

|origin-date={{circa}} 100–230 kya{{efn|group=note|"the synonymous mutation rate of Kivisild et al. [...] estimates the coalescence time of the mtDNA tree overall at ~160,000 kya [...] We present a revised chronology using the complete mtDNA genome rate and an ML approach for the mtDNA tree in Figure 6, with full details of the age estimates and associated 95% confidence regions in Table S5." See: [https://www.cell.com/cms/10.1016/j.ajhg.2009.05.001/attachment/dd25d63b-7e0f-4377-8e79-900694228888/mmc1.pdf Supplemental Data.]}}{{efn|group=note|"we estimate the time to the most recent common ancestor (TMRCA) of the Y chromosome to be 120 to 156 thousand years and the mitochondrial genome TMRCA to be 99 to 148 thousand years. Our findings suggest that, contrary to previous claims, male lineages do not coalesce significantly more recently than female lineages."{{cite journal |vauthors=Poznik GD, Henn BM, Yee MC, Sliwerska E, Euskirchen GM, Lin AA, Snyder M, Quintana-Murci L, Kidd JM, Underhill PA, Bustamante CD |display-authors=6 |title=Sequencing Y chromosomes resolves discrepancy in time to common ancestor of males versus females |journal=Science |volume=341 |issue=6145 |pages=562–565 |date=August 2013 |pmid=23908239 |pmc=4032117 |doi=10.1126/science.1237619 |bibcode=2013Sci...341..562P }}}}

|origin-place=East Africa

|ancestor=n/a

|descendants={{Unbulleted list|{{Nowrap|Haplogroup L0}}|{{Nowrap|Haplogroup L1-6}}}}

|mutations=None

}}

In human genetics, the Mitochondrial Eve (more technically known as the Mitochondrial-Most Recent Common Ancestor, shortened to mt-Eve or mt-MRCA) is the matrilineal most recent common ancestor (MRCA) of all living humans. In other words, she is defined as the most recent woman from whom all living humans descend in an unbroken line purely through their mothers and through the mothers of those mothers, back until all lines converge on one woman.

In terms of mitochondrial haplogroups, the mt-MRCA is situated at the divergence of macro-haplogroup L into L0 and L1–6. As of 2013, estimates on the age of this split ranged at around 155,000 years ago,{{efn|group=note|Two studies published in 2013 had 95% confidence intervals barely overlapping in the neighbourhood of 15 ka, a third study had a 95% confidence interval intermediate between the two others: "99 to 148 ka" according to Poznik, 2013 (ML whole-mtDNA age estimate: 178.8 [155.6; 202.2], ρ whole-mtDNA age estimate: 185.2 [153.8; 216.9], ρ synonymous age estimate: 174.8 [153.8; 216.9]), "134 to 188 ka", according to Fu, 2013, and 150 to 234 ka (95% CI) from Soares, 2009.}} consistent with a date later than the speciation of Homo sapiens but earlier than the recent out-of-Africa dispersal.{{cite journal |vauthors=Endicott P, Ho SY, Metspalu M, Stringer C |title=Evaluating the mitochondrial timescale of human evolution |journal=Trends in Ecology & Evolution |volume=24 |issue=9 |pages=515–521 |date=September 2009 |pmid=19682765 |doi=10.1016/j.tree.2009.04.006 }}{{cite web|url=https://www.leeds.ac.uk/news/article/245/new_molecular_clock_aids_dating_of_human_migration_history |publisher=University of Leeds |title=New 'molecular clock' aids dating of human migration history |date=3 June 2009 |access-date=23 December 2019}}

The male analog to the "Mitochondrial Eve" is the "Y-chromosomal Adam" (or Y-MRCA), the individual from whom all living humans are patrilineally descended. As the identity of both matrilineal and patrilineal MRCAs is dependent on genealogical history (pedigree collapse), they need not have lived at the same time. As of 2015, estimates of the age of the Y-MRCA range around 200,000 to 300,000 years ago, roughly consistent with the emergence of anatomically modern humans.{{cite journal |last1=Karmin |display-authors=etal |year=2015 |title=A recent bottleneck of Y chromosome diversity coincides with a global change in culture |journal=Genome Research |volume=25|issue=4|pages=459–66|doi=10.1101/gr.186684.114 |pmid=25770088 |pmc=4381518}} "we date the Y-chromosomal most recent common ancestor (MRCA) in Africa at 254 (95% CI 192–307) kya and detect a cluster of major non-African founder haplogroups in a narrow time interval at 47–52 kya, consistent with a rapid initial colonization model of Eurasia and Oceania after the out-of-Africa bottleneck. In contrast to demographic reconstructions based on mtDNA, we infer a second strong bottleneck in Y-chromosome lineages dating to the last 10 ky. We hypothesize that this bottleneck is caused by cultural changes affecting variance of reproductive success among males."

The name "Mitochondrial Eve" alludes to the biblical Eve, which has led to repeated misrepresentations or misconceptions in journalistic accounts on the topic. Popular science presentations of the topic usually point out such possible misconceptions by emphasizing the fact that the position of mt-MRCA is neither fixed in time (as the position of mt-MRCA moves forward in time as mitochondrial DNA (mtDNA) lineages become extinct), nor does it refer to a "first woman", nor the only living female of her time, nor the first member of a "new species".{{efn|group=note|"Caution: This does not make Mitochondrial Eve the first woman, or the first human, or the first member of a new species. Further Caution: This does not mean that other women alive when Eve was do not have descendants today; they simply do not have living descendants who are descended only through female links. Yet Further Caution: If a person were to be discovered whose mtDNA showed a pattern of mutations of greater time depth, then the status of Mitochondrial Eve would be reassigned to the most recent female ancestor shared by both that person and the person we now call Mitochondrial Eve."{{cite web |url=http://pages.ucsd.edu/~dkjordan/resources/clarifications/MitochondrialEve.html |title=Jordan: 'Mitochondrial Eve' |work=weber.ucsd.edu |year=2011 |access-date=7 January 2012}}}}

History

=Early research=

Early research using molecular clock methods was done during the late 1970s to early 1980s. Allan Wilson, Mark Stoneking, Rebecca L. Cann and Wesley Brown found that mutation in human mtDNA was unexpectedly fast, at 0.02 substitution per base (1%) in a million years, which is 5–10 times faster than in nuclear DNA.{{cite journal |vauthors=Brown WM, George M, Wilson AC |title=Rapid evolution of animal mitochondrial DNA |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=76 |issue=4 |pages=1967–1971 |date=April 1979 |pmid=109836 |pmc=383514 |doi=10.1073/pnas.76.4.1967 |doi-access=free |bibcode=1979PNAS...76.1967B }} Related work allowed for an analysis of the evolutionary relationships among gorillas, chimpanzees (common chimpanzee and bonobo) and humans.{{cite journal |vauthors=Ferris SD, Wilson AC, Brown WM |title=Evolutionary tree for apes and humans based on cleavage maps of mitochondrial DNA |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=78 |issue=4 |pages=2432–2436 |date=April 1981 |pmid=6264476 |pmc=319360 |doi=10.1073/pnas.78.4.2432 |doi-access=free |bibcode=1981PNAS...78.2432F }} With data from 21 human individuals, Brown published the first estimate on the age of the mt-MRCA at 180,000 years ago in 1980.{{cite journal |vauthors=Brown WM |title=Polymorphism in mitochondrial DNA of humans as revealed by restriction endonuclease analysis |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=77 |issue=6 |pages=3605–3609 |date=June 1980 |pmid=6251473 |pmc=349666 |doi=10.1073/pnas.77.6.3605 |doi-access=free |bibcode=1980PNAS...77.3605B }} A statistical analysis published in 1982 was taken as evidence for recent African origin (a hypothesis which at the time was competing with Asian origin of H. sapiens).{{cite journal |vauthors=Cann RL, Brown WM, Wilson AC |title=Evolution of human mitochondrial DNA: a preliminary report |journal=Progress in Clinical and Biological Research |volume=103 Pt A |issue=Pt A |pages=157–165 |year=1982 |pmid=6298804 }}{{cite journal |vauthors=Cann RL, Wilson AC |title=Length mutations in human mitochondrial DNA |journal=Genetics |volume=104 |issue=4 |pages=699–711 |date=August 1983 |pmid=6311667 |pmc=1202135 |doi=10.1093/genetics/104.4.699 }}

=1987 publication=

By 1985, data from the mtDNA of 145 women of different populations, and of two cell lines, HeLa and GM 3043, derived from an African American and a ǃKung respectively, were available. After more than 40 revisions of the draft, the manuscript was submitted to Nature in late 1985 or early 1986{{cite journal |vauthors=Cann R |title=All about mitochondrial eve: an interview with Rebecca Cann. Interview by Jane Gitschier |journal=PLOS Genetics |volume=6 |issue=5 |pages=e1000959 |date=May 2010 |pmid=20523888 |pmc=2877732 |doi=10.1371/journal.pgen.1000959 |doi-access=free }} and published on 1 January 1987. The published conclusion was that all current human mtDNA originated from a single population from Africa, at the time dated to between 140,000 and 200,000 years ago.{{cite journal |vauthors=Cann RL, Stoneking M, Wilson AC |title=Mitochondrial DNA and human evolution |journal=Nature |volume=325 |issue=6099 |pages=31–36 |year=1987 |pmid=3025745 |doi=10.1038/325031a0 |s2cid=4285418 |bibcode=1987Natur.325...31C }}

The dating for "Eve" was a blow to the multiregional hypothesis, which was debated at the time, and a boost to the theory of the recent origin model.{{cite journal |vauthors=Vigilant L, Stoneking M, Harpending H, Hawkes K, Wilson AC |title=African populations and the evolution of human mitochondrial DNA |journal=Science |volume=253 |issue=5027 |pages=1503–1507 |date=September 1991 |pmid=1840702 |doi=10.1126/science.1840702 |bibcode=1991Sci...253.1503V }}

Cann, Stoneking and Wilson did not use the term "Mitochondrial Eve" or even the name "Eve" in their original paper. It is however used by Cann in an article entitled "In Search of Eve" in the September–October 1987 issue of The Sciences.{{cite journal|vauthors=Cann RL |year=1987 |title=In Search of Eve |url=https://onlinelibrary.wiley.com/doi/abs/10.1002/j.2326-1951.1987.tb02967.x |journal=The Sciences |volume=27 |issue=5 |pages=30–37 |doi=10.1002/j.2326-1951.1987.tb02967.x}} It appears in the October 1987 article in Science by Roger Lewin, headlined "The Unmasking of Mitochondrial Eve".{{cite journal |vauthors=Lewin R |title=The unmasking of mitochondrial Eve |journal=Science |volume=238 |issue=4823 |pages=24–26 |date=October 1987 |pmid=3116666 |doi=10.1126/science.3116666 |bibcode=1987Sci...238...24L }} The biblical connotation was very clear from the start. The accompanying research news in Nature had the title "Out of the garden of Eden".{{cite journal |vauthors=Wainscoat J |title=Human evolution. Out of the garden of Eden |journal=Nature |volume=325 |issue=6099 |pages=13 |year=1987 |pmid=3796736 |doi=10.1038/325013a0 |s2cid=13187170 |bibcode=1987Natur.325...13W |doi-access=free }}

Wilson himself preferred the term "Lucky Mother"{{cite web|url=https://io9.gizmodo.com/the-scientists-behind-mitochondrial-eve-tell-us-about-t-5879991 |vauthors=Wilkins A |date=27 January 2012 |title=The scientists behind Mitochondrial Eve tell us about the 'lucky mother' who changed human evolution forever |work=Gizmodo |access-date=23 December 2019}} and thought the use of the name Eve "regrettable".{{cite book|vauthors=Cann RL |year=1997 |chapter=Chapter 4: Mothers, Labels, and Misogyny |title=Women in Human Evolution |editor=Hager LD |publisher=Routledge |location=London |pages=75–89 |isbn=9780415108331}} But the concept of Eve caught on with the public and was repeated in a Newsweek cover story (11 January 1988 issue featured a depiction of Adam and Eve on the cover, with the title "The Search for Adam and Eve"),{{cite web|vauthors=Tierney J |year=1992 |title=The Search for Adam and Eve|url=http://www.virginia.edu/woodson/courses/aas102%20(spring%2001)/articles/tierney.html |work=Newsweek |publisher=Carter G. Woodson Institute for Afro-American and African Studies |via=Internet Archive |archive-url=https://web.archive.org/web/20150320110036/http://www.virginia.edu/woodson/courses/aas102%20(spring%2001)/articles/tierney.html |access-date=21 July 2019|archive-date=20 March 2015 }} and a cover story in Time on 26 January 1987.{{cite magazine|vauthors=Lemonick MD |date=26 January 1987|title=Everyone's Genealogical Mother|url=http://www.time.com/time/magazine/article/0,9171,963320,00.html |archive-url=https://web.archive.org/web/20080923010301/http://www.time.com/time/magazine/article/0,9171,963320,00.html |url-status=dead |archive-date=23 September 2008 |magazine=Time |access-date=13 May 2013}}

=Reception and later research=

Shortly after the 1987 publication, its methodology and secondary conclusions were criticised.{{cite journal |vauthors=Darlu P, Tassy P |title=Disputed African origin of human populations |journal=Nature |volume=329 |issue=6135 |pages=111–112 |year=1987 |pmid=3114640 |doi=10.1038/329111b0 |s2cid=4313392 |bibcode=1987Natur.329..111D |doi-access=free }} Both the dating of mt-Eve and the relevance of the age of the purely matrilineal descent for population replacement were subjects of controversy during the 1990s;{{cite journal |vauthors=Maddison DR |title=African Origin of human mitochondrial DNA reexamined |journal=Systematic Zoology |volume=40 |issue=3 |pages=355–63 |year=1991 |doi=10.2307/2992327 |jstor=2992327 }}{{cite journal |vauthors=Nei M |title=Age of the common ancestor of human mitochondrial DNA |journal=Molecular Biology and Evolution |volume=9 |issue=6 |pages=1176–1178 |date=November 1992 |pmid=1435241 |doi=10.1093/oxfordjournals.molbev.a040785 |doi-access=free }}{{cite journal |vauthors=Ayala FJ |title=The myth of Eve: molecular biology and human origins |journal=Science |volume=270 |issue=5244 |pages=1930–1936 |date=December 1995 |pmid=8533083 |doi=10.1126/science.270.5244.1930 |s2cid=42801341 |doi-access=free |bibcode=1995Sci...270.1930A }}{{cite journal |vauthors=Templeton A |title=Out of Africa again and again |journal=Nature |volume=416 |issue=6876 |pages=45–51 |date=March 2002 |pmid=11882887 |doi=10.1038/416045a |s2cid=4397398 |bibcode=2002Natur.416...45T }} Alan Templeton (1997) asserted that the study did "not support the hypothesis of a recent African origin for all of humanity following a split between Africans and non-Africans 100,000 years ago" and also did "not support the hypothesis of a recent global replacement of humans coming out of Africa."{{cite journal |vauthors=Templeton AR |title=Out of Africa? What do genes tell us? |journal=Current Opinion in Genetics & Development |volume=7 |issue=6 |pages=841–847 |date=December 1997 |pmid=9468796 |doi=10.1016/S0959-437X(97)80049-4 }}

The placement by {{Harvtxt|Cann|Stoneking|Wilson|1987}} of a relatively small population of humans in sub-Saharan Africa was consistent with the hypothesis of Cann (1982) and lent considerable support for the "recent out-of-Africa" scenario.

In 1999, Krings et al. eliminated problems in molecular clocking postulated by Nei (1992){{cite journal |vauthors=Nei M |year=1992 |title=Age of the common ancestor of human mitochondrial DNA |url=https://www.researchgate.net/publication/21720959 |journal=Molecular Biology and Evolution |volume=9 |issue=6 |pages=1176–1178|doi=10.1093/oxfordjournals.molbev.a040785 |pmid=1435241 |doi-access=free }} when it was found that the mtDNA sequence for the same region was substantially different from the MRCA relative to any human sequence.{{cite journal |vauthors=Krings M, Salem AE, Bauer K, Geisert H, Malek AK, Chaix L, Simon C, Welsby D, Di Rienzo A, Utermann G, Sajantila A, Pääbo S, Stoneking M |display-authors=6 |title=mtDNA analysis of Nile River Valley populations: A genetic corridor or a barrier to migration? |language=English |journal=American Journal of Human Genetics |volume=64 |issue=4 |pages=1166–1176 |date=April 1999 |pmid=10090902 |pmc=1377841 |doi=10.1086/302314 }}{{cite journal |vauthors=Krings M, Stone A, Schmitz RW, Krainitzki H, Stoneking M, Pääbo S |title=Neandertal DNA sequences and the origin of modern humans |language=English |journal=Cell |volume=90 |issue=1 |pages=19–30 |date=July 1997 |pmid=9230299 |doi=10.1016/S0092-8674(00)80310-4 |s2cid=13581775 |doi-access=free |hdl=11858/00-001M-0000-0025-0960-8 |hdl-access=free }}

In 1997, {{Harvtxt|Parsons|Muniec|Sullivan|Woodyatt|1997}} published a study of mtDNA mutation rates in a single, well-documented family (the Romanov family of Russian royalty). In this study, they calculated a mutation rate upwards of twenty times higher than previous results.{{cite journal |last1=Parsons | first1 = Thomas J. |last2 = Muniec | first2 = David S. | last3 = Sullivan | first3= Kevin | last4 = Woodyatt | first4 = Nicola | last5= Alliston-Greiner | first5=Rosemary |last6 = Wilson | first6 = Mark R. |last7= Berry | first7= Dianna L. | last8 = Holland | first8 = Koren A. |last9 = Weedn | first9 = Viktor W. | last10 = Gill | first10 = Peter| last11= Holland | first11 = Mitchell M. |title=A high observed substitution rate in the human mitochondrial DNA control region |journal=Nature Genetics |volume=15 |issue=4 |pages=363–368 |date=April 1997 |pmid=9090380 |doi=10.1038/ng0497-363 |s2cid=32812244 }}

Although the original research did have analytical limitations, the estimate on the age of the mt-MRCA has proven robust.{{cite web|vauthors=Holsinger K|url=http://darwin.eeb.uconn.edu/eeb348/lecturenotes/coalescent/node5.html |title=(Mathematics of the coalescent) An example: Mitochondrial Eve |work=Holsinger Lab |date=29 September 2012 |access-date=16 May 2013}}{{cite journal |vauthors=Cyran KA, Kimmel M |title=Alternatives to the Wright-Fisher model: the robustness of mitochondrial Eve dating |journal=Theoretical Population Biology |volume=78 |issue=3 |pages=165–172 |date=November 2010 |pmid=20600209 |doi=10.1016/j.tpb.2010.06.001 }} More recent age estimates have remained consistent with the 140–200 kya estimate published in 1987: A 2013 estimate dated Mitochondrial Eve to about 160 kya (within the reserved estimate of the original research) and Out of Africa II to about 95 kya.{{cite journal |vauthors=Fu Q, Mittnik A, Johnson PL, Bos K, Lari M, Bollongino R, Sun C, Giemsch L, Schmitz R, Burger J, Ronchitelli AM, Martini F, Cremonesi RG, Svoboda J, Bauer P, Caramelli D, Castellano S, Reich D, Pääbo S, Krause J |display-authors=6 |title=A revised timescale for human evolution based on ancient mitochondrial genomes |journal=Current Biology |volume=23 |issue=7 |pages=553–559 |date=April 2013 |pmid=23523248 |pmc=5036973 |doi=10.1016/j.cub.2013.02.044 }} Another 2013 study (based on genome sequencing of 69 people from 9 different populations) reported the age of Mitochondrial Eve between 99 and 148 kya and that of the Y-MRCA between 120 and 156 kya.

Female and mitochondrial ancestry

{{further|Genetic genealogy (matrilineal)|Mitochondrial DNA|Human mitochondrial molecular clock}}

File:MtDNA-MRCA-generations-Evolution.svg or selection the female lineage will trace back to a single female, such as Mitochondrial Eve. In this example over five generations colors represent extinct matrilineal lines and black the matrilineal line descended from mtDNA MRCA.]]

Without a DNA sample, it is not possible to reconstruct the complete genetic makeup (genome) of any individual who died very long ago. By analysing descendants' DNA, however, parts of ancestral genomes are estimated by scientists. Mitochondrial DNA (mtDNA, the DNA located in mitochondria, different from the DNA in the nucleus of a cell) and Y-chromosome DNA are commonly used to trace ancestry in this manner. mtDNA is generally passed un-mixed from mothers to children of both sexes, along the maternal line, or matrilineally.{{cite journal |vauthors=Giles RE, Blanc H, Cann HM, Wallace DC |title=Maternal inheritance of human mitochondrial DNA |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=77 |issue=11 |pages=6715–6719 |date=November 1980 |pmid=6256757 |pmc=350359 |doi=10.1073/pnas.77.11.6715 |doi-access=free |bibcode=1980PNAS...77.6715G }}{{cite journal |vauthors=Birky CW |title=Uniparental inheritance of organelle genes |journal=Current Biology |volume=18 |issue=16 |pages=R692–R695 |date=August 2008 |pmid=18727899 |doi=10.1016/j.cub.2008.06.049 |s2cid=9866662 |doi-access=free }} Matrilineal descent goes back through mothers, to their mothers, until all female lineages converge.

Branches are identified by one or more unique markers which give a mitochondrial "DNA signature" or "haplotype" (e.g. the CRS is a haplotype). Each marker is a DNA base-pair that has resulted from an SNP mutation. Scientists sort mitochondrial DNA results into more or less related groups, with more or less recent common ancestors. This leads to the construction of a DNA family tree where the branches are in biological terms clades, and the common ancestors such as Mitochondrial Eve sit at branching points in this tree. Major branches are said to define a haplogroup (e.g. CRS belongs to haplogroup H), and large branches containing several haplogroups are called "macro-haplogroups".

File:Mitochondrial eve tree.gif

The mitochondrial clade which Mitochondrial Eve defines is the species Homo sapiens sapiens itself, or at least the current population or "chronospecies" as it exists today. In principle, earlier Eves can also be defined going beyond the species, for example one who is ancestral to both modern humanity and Neanderthals, or, further back, an "Eve" ancestral to all members of genus Homo and chimpanzees in genus Pan. According to current nomenclature, Mitochondrial Eve's haplogroup was within mitochondrial haplogroup L because this macro-haplogroup contains all surviving human mitochondrial lineages today, and she must predate the emergence of L0.

The variation of mitochondrial DNA between different people can be used to estimate the time back to a common ancestor, such as Mitochondrial Eve. This works because, along any particular line of descent, mitochondrial DNA accumulates mutations at the rate of approximately one every 3,500 years per nucleotide.{{cite journal |vauthors=Soares P, Ermini L, Thomson N, Mormina M, Rito T, Röhl A, Salas A, Oppenheimer S, Macaulay V, Richards MB |display-authors=6 |title=Correcting for purifying selection: an improved human mitochondrial molecular clock |journal=American Journal of Human Genetics |volume=84 |issue=6 |pages=740–759 |date=June 2009 |pmid=19500773 |pmc=2694979 |doi=10.1016/j.ajhg.2009.05.001 }}{{cite journal |vauthors=Gibbons A |title=Calibrating the mitochondrial clock |journal=Science |volume=279 |issue=5347 |pages=28–29 |date=January 1998 |pmid=9441404 |doi=10.1126/science.279.5347.28 |s2cid=29855766 |bibcode=1998Sci...279...28G }}{{efn|group=note|There are sites in mtDNA (such as: 16129, 16223, 16311, 16362) that evolve more rapidly, have been noted to change within intragenerational timeframes.{{cite journal |vauthors=Excoffier L, Yang Z |title=Substitution rate variation among sites in mitochondrial hypervariable region I of humans and chimpanzees |journal=Molecular Biology and Evolution |volume=16 |issue=10 |pages=1357–1368 |date=October 1999 |pmid=10563016 |doi=10.1093/oxfordjournals.molbev.a026046 |doi-access=free |ref=none}}}} A certain number of these new variants will survive into modern times and be identifiable as distinct lineages. At the same time some branches, including even very old ones, come to an end when the last family in a distinct branch has no daughters.

Mitochondrial Eve is the most recent common matrilineal ancestor for all modern humans. Whenever one of the two most ancient branch lines dies out (by producing only non-matrilinear descendants at that time), the MRCA will move to a more recent female ancestor, always the most recent mother to have more than one daughter with living maternal line descendants alive today. The number of mutations that can be found distinguishing modern people is determined by two criteria: first and most obviously, the time back to her, but second and less obviously by the varying rates at which new branches have come into existence and old branches have become extinct. By looking at the number of mutations which have been accumulated in different branches of this family tree, and looking at which geographical regions have the widest range of least related branches, the region where Eve lived can be proposed.

Popular reception and misconceptions

Newsweek reported on Mitochondrial Eve based on the Cann et al. study in January 1988, under a heading of "Scientists Explore a Controversial Theory About Man's Origins". The edition sold a record number of copies.

The popular name "mitochondrial Eve", of 1980s coinage, has contributed to a number of popular misconceptions. At first, the announcement of a "mitochondrial Eve" was even greeted with endorsement from young earth creationists, who viewed the theory as a validation of the biblical creation story.{{cite journal|vauthors=Wieland C |url=http://creation.com/mitochondrial-eve-and-biblical-eve-are-looking-good-criticism-of-young-age-is-premature|title=Mitochondrial Eve and biblical Eve are looking good: criticism of young age is premature|journal=Journal of Creation |volume=19|issue=1 |pages=57–59|year=2005}}{{cite web|vauthors=Nelson CW |url=http://www.answersingenesis.org/articles/tj/v17/n1/events |title=Genetics and Biblical Demographic Events |work=Answers in Genesis|date=1 April 2003 |access-date=16 May 2013}}{{cite web|vauthors=Oakes J|url=http://www.evidenceforchristianity.org/can-the-human-arguments-about-mitochondrial-eve-and-y-chromosome-adam-be-extended-to-the-animal-world-to-test-the-reality-of-the-flood-of-noahr/ |title=Can the human arguments about mitochondrial Eve and y-chromosome Adam be extended to the animal world to test the reality of the flood of Noah?|work=Evidence for Christianity |date=25 January 2007 |publisher=Answers in Genesis|access-date=16 May 2013}}{{npsn|date=February 2020}}

Due to such misunderstandings, authors of popular science publications since the 1990s have been emphatic in pointing out that the name is merely a popular convention, and that the mt-MRCA was not in any way the "first woman".{{cite book |vauthors=Dawkins R |title=The ancestor's tale: a pilgrimage to the dawn of evolution |publisher=Houghton Mifflin |location=Boston |year=2004 |isbn=978-0-618-00583-3 |title-link=The Ancestor's Tale }} Her position is purely the result of genealogical history of human populations later, and as matrilineal lineages die out, the position of mt-MRCA keeps moving forward to younger individuals over time.

In River Out of Eden (1995), Richard Dawkins discussed human ancestry in the context of a "river of genes", including an explanation of the concept of Mitochondrial Eve.{{cite book |vauthors=Dawkins R |title=River out of eden: a Darwinian view of life|url=https://books.google.com/books?id=DxmKvnPyBSoC&pg=PP1|access-date=5 December 2011|year=1995|publisher=Basic Books|isbn=978-0-465-06990-3}} The Seven Daughters of Eve (2002) presented the topic of human mitochondrial genetics to a general audience.{{cite book |vauthors=Sykes B |title=The Seven Daughters of Eve: The Science That Reveals Our Genetic Ancestry|year=2002|publisher=W. W. Norton & Company|isbn=978-0-393-32314-6|url-access=registration|url=https://archive.org/details/sevendaughtersof00brya}} The Real Eve: Modern Man's Journey Out of Africa by Stephen Oppenheimer (2003){{cite book |vauthors=Oppenheimer S |title=The Real Eve: Modern Man's Journey Out of Africa |year=2003 |location=New York |publisher=Basic Books |isbn=978-0-7867-1192-5 |url=https://books.google.com/books?id=5tP5Wb92wT4C }} was adapted into a 2002 Discovery Channel documentary.{{Cite book |last=Oppenheimer |first=Stephen |url=https://books.google.com/books?id=5tP5Wb92wT4C |title=The Real Eve: Modern Man's Journey Out of Africa |date=2003 |publisher=Carroll & Graf |isbn=978-0-7867-1192-5 |language=en}}

=Not the only woman=

One common misconception surrounding Mitochondrial Eve is that since all women alive today descended in a direct unbroken female line from her, she must have been the only woman alive at the time. However, nuclear DNA studies indicate that the effective population size of ancient humans never dropped below tens of thousands.{{cite journal |vauthors=Takahata N |title=Allelic genealogy and human evolution |journal=Molecular Biology and Evolution |volume=10 |issue=1 |pages=2–22 |date=January 1993 |pmid=8450756 |doi=10.1093/oxfordjournals.molbev.a039995 |doi-access=free }} Other women living during Eve's time may have descendants alive today but not in a direct female line.{{Cite web |date=14 January 2008 |title=Are we all descended from a common female ancestor? |url=https://science.howstuffworks.com/life/evolution/female-ancestor.htm |access-date=17 May 2022 |website=HowStuffWorks |language=en}}

=Not a fixed individual over time=

File:MtDNA-MRCA-generations-Evolution-new Eve.svg

The definition of Mitochondrial Eve is fixed, but the woman in prehistory who fits this definition can change. That is, not only can our knowledge of when and where Mitochondrial Eve lived change due to new discoveries, but the actual Mitochondrial Eve can change. The Mitochondrial Eve can change, when a mother-daughter line comes to an end. It follows from the definition of Mitochondrial Eve that she had at least two daughters who both have unbroken female lineages that have survived to the present day. In every generation mitochondrial lineages end – when a woman with unique mtDNA dies with no daughters. When the mitochondrial lineages of daughters of Mitochondrial Eve die out, then the title of "Mitochondrial Eve" shifts forward from the remaining daughter through her matrilineal descendants, until the first descendant is reached who had two or more daughters who together have all living humans as their matrilineal descendants. Once a lineage has died out it is irretrievably lost and this mechanism can thus only shift the title of "Mitochondrial Eve" forward in time.{{cite magazine|vauthors=Learn JP |title=No, a Mitochondrial 'Eve' Is Not the First Female in a Species|url=https://www.smithsonianmag.com/science-nature/no-mitochondrial-eve-not-first-female-species-180959593/|access-date=23 February 2021|magazine=Smithsonian Magazine|language=en}}

Because mtDNA mapping of humans is very incomplete, the discovery of living mtDNA lines which predate our current concept of "Mitochondrial Eve" could result in the title moving to an earlier woman. This happened to her male counterpart, "Y-chromosomal Adam", when an older Y line, haplogroup A-00, was discovered.{{cite journal |vauthors=Mendez FL, Krahn T, Schrack B, Krahn AM, Veeramah KR, Woerner AE, Fomine FL, Bradman N, Thomas MG, Karafet TM, Hammer MF |display-authors=6 |title=An African American paternal lineage adds an extremely ancient root to the human Y chromosome phylogenetic tree |journal=American Journal of Human Genetics |volume=92 |issue=3 |pages=454–459 |date=March 2013 |pmid=23453668 |pmc=3591855 |doi=10.1016/j.ajhg.2013.02.002 }}

=Not necessarily a contemporary of "Y-chromosomal Adam"=

Sometimes Mitochondrial Eve is assumed to have lived at the same time as Y-chromosomal Adam (from whom all living males are descended patrilineally), and perhaps even met and mated with him. Even if this were true, which is currently regarded as highly unlikely, this would only be a coincidence. Like Mitochondrial "Eve", Y-chromosomal "Adam" probably lived in Africa. A recent study (March 2013) concluded however that "Eve" lived much later than "Adam" – some 140,000 years later.{{cite magazine |url=https://www.newscientist.com/article/dn23240-the-father-of-all-men-is-340000-years-old/ |title=The father of all men is 340,000 years old |magazine=New Scientist |date=6 March 2013 |access-date=13 March 2013 |vauthors=Barras C }} (Earlier studies considered, conversely, that "Eve" lived earlier than "Adam".){{cite journal |vauthors=Cruciani F, Trombetta B, Massaia A, Destro-Bisol G, Sellitto D, Scozzari R |title=A revised root for the human Y chromosomal phylogenetic tree: the origin of patrilineal diversity in Africa |journal=American Journal of Human Genetics |volume=88 |issue=6 |pages=814–818 |date=June 2011 |pmid=21601174 |pmc=3113241 |doi=10.1016/j.ajhg.2011.05.002 }} More recent studies indicate that it is not impossible that Mitochondrial Eve and Y-chromosomal Adam might have lived around the same time.{{cite journal|url=http://www.nature.com/news/genetic-adam-and-eve-did-not-live-too-far-apart-in-time-1.13478 |title=Genetic Adam and Eve did not live too far apart in time |vauthors=Callaway E |date=6 August 2013 |journal=Nature |doi=10.1038/nature.2013.13478|s2cid=170608686 }}

=Not the most recent ancestor shared by all humans=

Mitochondrial Eve is the most recent common matrilineal ancestor, not the most recent common ancestor. Since the mtDNA is inherited maternally and recombination is either rare or absent, it is relatively easy to track the ancestry of the lineages back to a MRCA; however, this MRCA is valid only when discussing mitochondrial DNA. An approximate sequence from newest to oldest can list various important points in the ancestry of modern human populations:

The human MRCA. The time period that human MRCA lived is unknown. Rohde et al put forth a "rough guess" that the MRCA could have existed 5000 years ago; however, the authors state that this estimate is "extremely tentative, and the model contains several obvious sources of error, as it was motivated more by considerations of theoretical insight and tractability than by realism."{{cite journal |vauthors=Rohde DL, Olson S, Chang JT |title=Modelling the recent common ancestry of all living humans |journal=Nature |volume=431 |issue=7008 |pages=562–566 |date=September 2004 |pmid=15457259 |doi=10.1038/nature02842 |s2cid=3563900 |citeseerx=10.1.1.78.8467 |bibcode=2004Natur.431..562R }} Just a few thousand years before the most recent single ancestor shared by all living humans was the time at which all humans who were then alive either left no descendants alive today or were common ancestors of all humans alive today. However, such a late date is difficult to reconcile with the geographical spread of our species and the consequent isolation of different groups from each other. For example, it is generally accepted that the indigenous population of Tasmania was isolated from all other humans between the rise in sea level after the last ice age some 8000 years ago and the arrival of Europeans. Estimates of the MRCA of even closely related human populations have been much more than 5000 years ago.{{Cite journal |last1=Zhou |first1=Jin |last2=Teo |first2=Yik-Ying |date=August 2016 |title=Estimating time to the most recent common ancestor (TMRCA): comparison and application of eight methods |journal=European Journal of Human Genetics |language=en |volume=24 |issue=8 |pages=1195–1201 |doi=10.1038/ejhg.2015.258 |pmid=26669663 |pmc=4970674 |s2cid=965600 |issn=1476-5438|doi-access=free }}
The identical ancestors point. In other words, "each present-day human has exactly the same set of genealogical ancestors" alive at the "identical ancestors point" in time. This is far more recent than when Mitochondrial Eve was proposed to have lived.
Mitochondrial Eve, the most recent female-line common ancestor of all living people.
"Y-chromosomal Adam", the most recent male-line common ancestor of all living people.

Notes

References

External links

{{Spoken Wikipedia|Mitochondrial Eve.ogg|date=22 April 2005|SubCat=}}

[http://www.talkorigins.org/faqs/homs/mitoeve.html Krishna Kunchithapadam, "What, if anything, is a Mitochondrial Eve?"] a simple explanation
[https://www.youtube.com/watch?v=9wS1za00mMM&feature=&p=A0D41D79D1CE0DBB&index=0&playnext=1 The Real Eve: Modern Man's Journey Out of Africa] – by Stephen Oppenheimer – Discovery Channel, 2002

Human mtDNA haplogroups

Category:Human mitochondrial genetics

Category:Genetic genealogy

Category:Recent African origin of modern humans

Category:Female

Category:Hebrew Bible in popular culture

Category:Women in Africa

Category:Women's history

Category:Events in biological evolution