Scientists have pinpointed three genes that may have played a pivotal role in the evolution of the striking increase in brain size that helped define what it means to be human.
These genes, found only in people, appeared between 3 and 4 million years ago, just prior to a period when the fossil record demonstrates a dramatic brain enlargement in ancestral species in the human lineage, researchers said on Thursday.
The three nearly identical genes, as well as a fourth nonfunctional one, are called NOTCH2NL genes. They are from a family of genes that date back hundreds of millions of years and are heavily involved in embryonic development.
With your current subscription plan you can comment on stories. However, before writing your first comment, please create a display name in the Profile section of your subscriber account page.