"Mitochondrial Eve" has aged one and a half times?
The age of the "mitochondrial Eve" has been clarified<url>
Researchers have clarified the age of the "mitochondrial Eve" – a woman who was the closest ancestor of all humans of the species Homo sapiens.
According to new data, taking into account the latest achievements in the field of population genetics, Eve lived about 200 thousand years ago. Previously, the age of a hypothetical woman was estimated at 140 thousand years. The work of scientists (Krzysztof A. Cyran and Marek Kimmel, Alternatives to the Wright–Fisher model: The robustness of mitochondrial Eve dating) is published in the journal Theoretical Population Biology, and its summary can be found in the press release of Rice University (USA): 'Mitochondrial Eve': Mother of All Humans Lived 200,000 Years Ago.
It is possible to determine when exactly a woman lived, who is the ancestor of all people on Earth, due to the fact that human cells contain special organelles – mitochondria. They provide the cell with energy and carry a small genome of their own. Mitochondria are passed from generation to generation through the female line – these organelles are contained in the mother's egg, which then develops into a full-fledged embryo. Thus, the mitochondria of all H.sapiens living on Earth are direct descendants of the mitochondria of the very first representatives of this species.
In the mitochondrial genome, as well as in the nuclear genome, mutations accumulate over time. If mutations do not impair the functioning of mitochondrial genes, then they can be preserved and transmitted in a series of generations. Due to the fact that the rate of accumulation of changes is approximately constant over time, comparing the number of mutations in different people, scientists can calculate how long ago their common ancestors diverged. This method is called the molecular clock method.
All such works are based on theoretical calculations describing how the processes of crossing individuals and the development of populations occur. Any such assumptions contain many conventions that can significantly distort the result. For example, it is often assumed that interbreeding occurs evenly throughout the population (that is, any two of its representatives of the opposite sex can have offspring with equal probability). In addition, different models may be based on different assumptions about population growth over time.
As the authors of the new study write, when assessing the age of the "mitochondrial Eve", they tried to take into account as much as possible all existing considerations and models that reduce the uncertainty of the final result.
Studies of the "mitochondrial Eve", as well as the "Y-chromosomal Adam" – the common ancestor of all men living on Earth – will allow specialists to find out how the early stages of human evolution proceeded, in particular, when and where the existing ethnic groups and races stood out.
Portal "Eternal youth" http://vechnayamolodost.ru23.08.2010