How many ‘evas’ were there at the beginning of our species? | we answer | The USA Print

The history of the Mitochondrial Black Eve arose in 1987 when, based on the evolutionary theory of repopulation of the world by Homo sapiens From Africa, Rebecca Cann and Mark Stoneking studied 147 genomes (145 from placenta and 2 female cell lines) present in mitochondria and from 5 different geographical origins.

These DNAs included 20 samples from Sub-Saharan Africa, 34 Asians (China, Vietnam, Laos, the Philippines, Indonesia, and Tonga), 46 Caucasians (Europe, North Africa, and the Middle East), 21 Australian Aborigines, and 26 from New Guinea. As the DNA present in the mitochondria is inherited exclusively through the mother, it constitutes a fundamental tool for studying the migrations of women.

To do this, and given that DNA presents sequence recognition regions by restriction enzymes, Cann performed analyzes of all the samples with 12 different enzymes that recognized the most common mutations and observed that the genomes presented different cutting patterns (defining this or that). there is not each certain mutation) depending on its geographical origin. Thus, they were able to classify the genomes positive/negative for mutations and build a phylogenetic tree. Their observations indicated an association of the presence of certain mutations in specific groups of each geographic population.

These population groups today are called mitochondrial haplogroups and originate from the original Eve or black Eve, which is from the L0 haplogroup. The calculation is that that mitochondrial black Eve, or that group of evasThey lived about 200,000 years ago in Africa.

Figure extracted from Chinnery & Gómez-Durán in the journal ‘Frontiers in Neuroscience’ 2018, Volume 12

For that reason, according to Cann’s theory, it was proposed that there is the origin of our first woman. However, the mitochondrial phylogenetic tree is much more complex. Since leaving Africa, and on the African continent itself, many other groups arose (new mutations that produce new patterns of enzyme cutting, although sequencing is used today) that gave rise to more subgroups.

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For example, in Europe there are eight Caucasian haplogroups and in Asia five, however, within them there are sub-branches and sub-branches that have also been separating, since each time a new mutation arises and it expands with new female carriers. create a new branch of the tree.

Answering the question, we can conclude that we know that there is a black Eve that generated the main sequence, but in turn the population groups in each continent have subbranches and their own evas mitochondrial. Thus, it could be said that there is one or several evas black.

How he does it is another good question.

Aurora Gomez-Duran is a principal investigator at the CiMUS – Singular Center for Research in Molecular Medicine and Chronic Diseases of the University of Santiago de Compostela

Question sent by Jorge Testart Tobar

Coordination and writing:Victoria Bull

we answer is a weekly scientific consultancy, sponsored by theDr. Antoni Esteve Foundationand the programL’Oréal-Unesco ‘For Women in Science’, which answers readers’ questions about science and technology. They are scientists and technologists, members ofAMIT (Association of Women Researchers and Technologists), which answer those questions. Send your questions to[email protected]or by Twitter #werespond.

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