You Look Like a Monkey and Smell Like One Too

To find the parts of our genome that make us human, scientists wrote a computer program that searched for the DNA sequences that have changed the most since humans and chimpanzees diverged from their last common ancestor. Topping the list was a 118-letter snippet of code known as human accelerated region 1 (HAR1). This region of the genome changed very little for most of vertebrate evolution, with chimp and chicken sequences differing by just two letters. Human and chimp HAR1s, however, differ by 18 letters, suggesting that HAR1 acquired an important new function in humans.

Below is the same snippet of HAR1 DNA showing the difference between chicken (bottom), chimp (middle) and man (top) with color blocks denoting DNA changes from the previous iteration. >> Source: Scientific American (May 2009)

.