Gene regulation by body difference between humans and chimps

Its not the genes but how the body regulates their formation that accounts for the difference between species, according to a new study in this weeks issue of the journal Science.

Washington, Aug 10 : Its not the genes but how the body regulates their formation that accounts for the difference between species, according to a new study in this week's issue of the journal Science.

"We've known for a while that the protein coding genes of humans and chimpanzees are about 99 percent the same. The challenge for biologists is accounting for what causes the substantial difference between the person and the chimp," said senior author Michael Snyder, the Cullman Professor of Molecular Cellular and Developmental Biology at Yale.

In the study, Prof. Snyder and his team found the DNA binding sites by aiming at their function, rather than their sequence, in yeast.

First, they isolated transcription factors that were specifically bound to DNA at their promoter sites. Then they analyzed the sequences that were isolated to determine the similarities and differences in regulatory regions between the different species.

"By using a group of closely and more distantly related yeast whose sequences were well documented, we were able to see functional differences that had been invisible to researchers before," said Prof. Snyder.

Till now, comparing gene regulation across similar organisms has been difficult, because the nucleotide sequence of DNA regulatory regions, or promoters, is more variable than the sequences of their corresponding protein-coding regions.

This makes them harder to identify by standard computer comparisons.

"We expect that this approach will get us closer to understanding the balance between gene content and gene regulation in the question of human-chimp diversity," said Prof. Snyder.

"While many molecules that bind DNA regulatory regions have been identified as transcription factors mediating gene regulation, we have now shown that we can functionally map these interactions and identify the specific targeted promoters.

"We were startled to find that even the closely related species of yeast had extensively differing patterns of regulation," he said.

ANI