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Genetic “Adam” Lived 239,000 Years Ago, Landmark Study Says

By Nayomi Chibana | Mar 27, 2015 04:22 PM EDT

In a study which involved the largest set of genomes from a single human population, scientists have found data that suggests the most recent common male ancestor of humanity lived 239,000 years ago and that he probably lived at around the same time as genetic "Eve" - the last woman to whom all females can trace their DNA.

The results of the research are game-changing considering that scientists previously thought that genetic "Adam" - humanity's most recent common male ancestor - was 100,000 years older than his female counterpart. Since genetic "Adam" is now thought to have lived between 174,000 and 321,000 years ago, while genetic "Eve" is believed to have existed approximately 200,000 years ago, it is probable that both were alive at the same time.

This new estimate for Adam's age makes more sense, according to researchers. It also suggests that humanity is evolving at a much faster rate than previously thought. A previous study conducted by researchers at the University of Wisconsin found that at least 7% of human genes have undergone recent evolution, such as the appearance of fair skin and blue eyes in northern Europe. 

In the unprecedented task of sequencing the DNA of 2,636 Icelanders and comparing them with the partial sequences of another 104,000, researchers have also found data that will help them discover mutant genes. So far, they have already found genes that increase the risks of Alzheimer's disease, liver and thyroid problems.

Since the Icelandic population has been isolated from other ethnic groups and, as a result, has little genetic diversity, researchers indicate that it is ideal for identifying genes that raise the risk of certain illnesses. Already, the study's data set has been used in four other studies, ranging from research into knocked out genes in the population to finding rare genetic mutations.

According to the Daily Mail, one of these studies reveals that 8,000 Icelanders have a least one gene of their 21,000 genes that doesn't function at all. Additionally, it was found that the most common muted genes were those associated with a person's sense of smell, and that, overall, 1,171 different genes had been silenced.

"This is very much more than a molecular national selfie," he added. "We're contributing to important tools for making more accurate diagnostics for rare diseases," said Kari Stefansson, founder of DeCode, the company which led the research.

Some scientists, however, are wary of generalizing results based on a set of genomes from such an isolated population as the Icelanders.

Andrew Allen, a geneticist at Duke University who didn't take part in the studies told The Verge in a n interview that this means that the "sample studied is not exactly healthy, is somewhat opportunistic, and probably doesn't correspond to any 'real' population." 

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