Genes -- And How Humans Got Their Dexterity (broadcast Friday, September 12th, 2008)

A rapidly evolving sequence from the human genome, HACNS1, drives gene activity in the developing thumb, wrist and ankle of mouse embryos. Yale University image.

We use our hands to play flamenco guitar, crochet a sweater and grip a baseball bat...but how did we get such great dexterity? In this segment of Science Friday, guest host Joe Palca takes a look at how humans came up with such a great hand. Research published recently in the journal Science says that one rapidly mutating genetic sequence may be part of the key to our tool-wielding prowess, upright gait, and more. The changing sequence, named HACNS1 by the researchers, is present and stable in many vertebrate species -- but that portion of the genome has developed several variations in the 6 million years since humans and chimpanzees diverged on the evolutionary family tree, the researchers say. Using experiments on mice, they determined that the HACNS1 region may be responsible for regulating the genes that control hand and limb formation in embryos. We'll talk about the work and what it means. Teachers, find more information about using Science Friday as a classroom resource in the Kids' Connection.