Mitochondrial Eve Totally Explained

Everything about Mitochondrial Eve totally explained

Mitochondrial Eve (mt-mrca) is the name given by researchers to the woman who is defined as the matrilineal most recent common ancestor (MRCA) for all currently living humans. Passed down from mother to offspring, her mitochondrial DNA (mtDNA) is now found in all living humans: every mtDNA in every living person is derived from hers. Mitochondrial Eve is the female counterpart of Y-chromosomal Adam, the patrilineal most recent common ancestor, although they lived at different times. She is believed to have lived about 140,000 years ago in what is now Ethiopia, Kenya or Tanzania. The time she lived is calculated based on the molecular clock technique of correlating elapsed time with observed genetic drift.
Mitochondrial Eve is the most recent common ancestor (MRCA) of all humans via the mitochondrial DNA pathway, not the unqualified MRCA of all humanity. All living humans can trace their ancestry back to the MRCA via at least one of their parents, but Mitochondrial Eve is defined via the maternal line. Therefore, she necessarily lived at least as long, though likely much longer, ago than the MRCA of all humanity.
The existence of Mitochondrial Eve and Y-chromosomal Adam nor imply neither deny the existence of population bottlenecks or a first couple. They each lived within a large human population at a different time.

Matrilineal descent

Mitochondrial Eve is the most recent common ancestor of all humans via the mitochondrial DNA pathway. In other words, she's the MRCA found when ancestry of all living humans is traced back in time, following only the maternal lineage. The mitochondrial DNA pathway is equivalent to maternal lineage, because mitochondrial DNA is only passed down from mother to child, never father to child.
To find the Mitochondrial Eve of all living humans, one can start by tracing a line from every individual to his/her mother, then continue those lines from each of those mothers to their mothers and so on, effectively tracing a family tree backward in time based purely on mitochondrial lineages. Going back through time these mitochondrial lineages will converge when two or more women have the same mother. The further back in time one goes, the fewer mitochondrial ancestors of living humans there will be. Eventually only one is left, and this one is the most recent common matrilineal ancestor of all humans alive today, for example Mitochondrial Eve.
It is possible to draw the same matrilineal tree forward in time by starting with all human female contemporaries of Mitochondrial Eve. Some of these women may have died childless. Others left only male children. For the rest who became mothers with at least one daughter, one can trace a line forward in time connecting them to their daughter(s). As the forward lineages progress in time, more and more lineage lines become extinct, as the last female in a line dies childless or leaves no female children. Eventually, only one single lineage remains, which includes all mothers, and in the next generation, all people, and hence all people alive today.

Misconceptions

Mitochondrial Eve is the most recent common matrilineal ancestor, not the most recent common ancestor (MRCA) of all humans. The MRCA's offspring have led to all living humans via sons and daughters, but Mitochondrial Eve must be traced only through female lineages, so she's estimated to have lived much longer ago than the MRCA. While Mitochondrial Eve is thought to have been living around 140,000 years ago, according to probabilistic studies, the MRCA could have been living as recently as 3,000 years ago. Allan Wilson's naming Mitochondrial Eve after Eve of the Genesis creation story has led to some misunderstandings among the general public. A common misconception is that Mitochondrial Eve was the only living human female of her time. While it's theoretically possible that she was the only human female of her time; had she been the only living female of her time, humanity would most likely have become extinct due to an extreme population bottleneck.
Indeed, not only were many women alive at the same time as Mitochondrial Eve but many of them have descendants alive today. They may have left descendants via either son or daughters (and grandsons or granddaughters, and so on). Nuclear genes from these contemporary women of Mitochondrial Eve are present in today's population, but mitochondrial DNA from them is not.

Mitochondrial DNA

Mitochondrial organelles, which contain mitochondrial DNA (mtDNA), are passed only from mother to offspring. A comparison of DNA sequences from mtDNA in a population reveals a molecular phylogeny. Unlike mtDNA, which is outside the nucleus, genes containing nuclear DNA become recombined after being inherited from both parents, and therefore we can be statistically less certain about nuclear DNA origins than we can for mtDNA, which is only inherited from the mother. mtDNA also mutates at a higher rate compared to nuclear DNA, so it gives researchers a more useful, magnified view of the diversity present in a population.
Just as mitochondria are inherited matrilineally, Y-chromosomes are inherited patrilineally. Thus it's possible to apply the same principles outlined above to men. The common patrilineal ancestor of all humans alive today has been dubbed Y-chromosomal Adam. Importantly, the genetic evidence suggests that the most recent patriarch of all humanity is much more recent than the most recent matriarch, suggesting that 'Adam' and 'Eve' were not alive at the same time. While 'Eve' is believed to be alive 140,000 years ago, 'Adam' lived only 60,000 years ago. repeated the study while avoiding its major pitfalls:

They sampled 53 persons, 32 of whom were Africans from different regions of sub-Saharan Africa.

They sequenced the complete mtDNA but excluded the rapidly evolving D-loop in the analysis.

An outgroup (chimpanzee) mtDNA sequence was used to root the tree (outgroup rooting). Outgroup rooting is much more reliable than midpoint rooting. The study by Ingman et al. verifies the major conclusions of Cann et al. of an African origin of human mtDNA within the past 172 000 ± 50 000 years.

In popular culture

Bryan Sykes has written a popular science book entitled The Seven Daughters of Eve.

In River Out of Eden, Richard Dawkins discusses human ancestry in the context of a river of genes and shows that Mitochondrial Eve is one of the many common ancestors we can trace back to via different gene pathways.

The Discovery Channel produced a documentary entitled The Real Eve, based on the book Out of Eden by Stephen Oppenheimer.

The Japanese novel, horror film and video game series Parasite Eve uses the Mitochondrial Eve theory as the basis for a fantasy about a scientist resurrecting his wife by regenerating her liver cells, with disastrous effects.

Greg Egan has written a short story called "Mitochondrial Eve".

The anime/manga series K.R.I.E.G made several references to mitochondria and the existence of the Mitochondrial Eve theory, among many other theories of evolution and human creation.

Arthur C. Clarke's novel The Light of Other Days describes a sequence where mitochondrial DNA is visually traced back to a Mitochondrial Eve.

The manga series Elfen Lied also mentions Mitochondrial Eve, with the suggestion of creating a new race, with a new Mitochondrial Eve.Further Information

Get more info on 'Mitochondrial Eve'.

External Link Exchanges

Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:

<a href="http://mitochondrial_eve.totallyexplained.com">Mitochondrial Eve Totally Explained</a>

Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned.