In this week's Science, two research groups publish separate reports indicating that most recent common male ancestor of Homo sapiens can be traced back to around the same time as the most recent common female ancestor. These findings contradict previous reports that the so-called mitochondrial "Eve" appeared long before the most recent male ancestor, Y-chromosome "Adam."
In one study, Stanford University investigators sequenced the genomes of 69 males from nine different populations, noting thousands of mutations that have influenced the Y chromosome and finding that most recent common ancestor of the Y chromosome lived between 120,000 years to 156,000 years ago. Applying the same techniques to mitochondrial DNA, they pinpointed the origin of the modern human maternal lineage around 99,000 and 148,000 years ago.
Meanwhile, an Italian team details the genetic analysis of 1,204 men from the isolated Mediterranean island of Sardinia. They, too, found thousands of Y chromosome-influencing mutations and suggested that human paternal lineages coalesced between 180,000 years and 200,000 years ago.
For more on these two studies, check out this GenomeWeb Daily News article.
Also in Science, two University of Cambridge scientists discuss the "sociability" of RNA. RNA, they write, can influence gene expression through various mechanisms such as RNA interference, and it has been suggested to not only operate within a cell but travel outside it. In their perspective article, the researchers explore the possibility that RNA could travel between organisms, and call for additional research to fully understand RNA. " Is there an extensive life for RNA molecules outside of the cell, and even outside of the organism that produced them?" they ask. "Investigating possible examples of “social RNA” presents an exciting avenue for future research, as the implications of such a phenomenon would be far-reaching indeed."