Thaindian News

Washington, Aug 18 (ANI): Eve, the maternal ancestor of all humans, lived about 200,000 years ago, confirms a new study.

The Rice University study was based on a side-by-side comparison of 10 human genetic models that each aim to determine when Eve lived.

“Our findings underscore the importance of taking into account the random nature of population processes like growth and extinction,” said study co-author Marek Kimmel.

Studying patterns of genetic variability in general are very important to medicine, he said.

Using mitochondrial genomes to gauge relatedness is a way for geneticists to simplify the task of finding common ancestors that lived long ago.

Comparing the differences among the 20,000 plus genes of the entire human genome is impossible, even with supercomputers.

But mitochondria — the tiny organelles that serve as energy factories inside all human cells — have their own genome. Because each person’s mitochondrial genome is inherited from his or her mother, all mitochondrial lineages are maternal.

“So, for instance, what is the rate of genetic mutation, and is that rate of change uniform in time? And what about the process of random loss of genetic variants, which we call genetic drift?” asks Krzysztof Cyran.

The answers to these questions take the form of coefficients — numeric constants that are plugged into the equation that returns the answer for when mtEve lived.

Each model has its own assumptions, and each assumption has mathematical implications.

“We found that all of the models that accounted for random population size — such as different branching processes — gave similar estimates. This is reassuring, because it shows that refining the assumptions of the model, beyond a certain point, may not be that important in the big picture,” Kimmel said.

The research is available online in the journal Theoretical Population Biology. (ANI)