Research sheds light on evolution

A recently discovered brain regulatory gene provides new evidence that humans evolved from lower primates. The gene, prodynorphin, was discovered by a team of researchers including Matthew Rockwell, a visiting research fellow in the Lewis- Sigler Institute for Integrative Genomics.

Prodynorphin, which is found in the brain, affects memory and perception. It is the body's "own form of heroin," Rockman said, and "makes a big difference on how people perceive reality."

The team published its results in this month's issue of the Public Library of Science. Their research compares the presence of the prodynorphin gene in lower primates and humans. While the gene that actually produces the prodynorphin appears to be the same in all humans and in lower primates, the variations in the amount produced from person to person and species to species suggest the influence of regulatory DNA.

Until now, researchers have primarily focused on protein sequences when studying gene mutations. The function of a gene, however, can be altered without a mutation of the protein sequence.

In fact, it is believed that much of evolution isn't due to changes in protein sequences, but rather to changes in regulatory DNA, which does not influence protein structure. Regulatory DNA influences when, where and to what extent the gene is expressed. This regulatory DNA is harder to study because it doesn't have a code — at least, not one that is known.

Rockman's research is significant because it represents "the very first time that we have identified a piece of non-protein coding DNA that has been altered by natural selection," Rockman said.

"Finding out what this does will give us some insight into what features of our humanness are the result of human evolution," Rockman added. Though it is just speculation at this point, "we can imagine that this evolutionary episode contributed to the way we perceive the world."

Through the study of more regulatory genes, researchers hope to better determine what role natural selection played in the evolution of humans.

The research for this discovery was part of Rockman's Ph.D. thesis at Duke University. As part of his postdoctoral study at Princeton, Rockman is continuing with similar research on regulatory genes in yeast and in C. elegans worms.