UC Santa Cruz scientists contribute to analysis of chimp genome SANTA CRUZ, CA--New insights into the genetic differences between humans and chimpanzees, our closest relatives on the tree of life, are emerging from a comparative analysis of the genomes of the two species. Researchers at the University of California, Santa Cruz, are part of an international team of scientists that has just published the first results from this analysis in the September 1 issue of the journal Nature. "The chimp genome sequence offers an unprecedented opportunity to understand primate evolution and to identify the genetic changes that gave rise to the modern human species. It's our first chance to see which parts of our genome are distinctly human," said Katherine Pollard, a postdoctoral researcher in UCSC's Center for Biomolecular Science and Engineering (CBSE) and a coauthor of one of four papers on the chimpanzee genome published this week in Nature. The paper presents a catalog of the genetic differences that have accumulated since the lineages that led to modern humans and chimpanzees diverged from a common ancester about 6 million years ago. The researchers have identified several regions of the human genome that bear the hallmarks of strong natural selection, whereas the corresponding chimpanzee sequences do not. These sequences may hold the most promise for determining human-specific traits such as language. The analysis was carried out by the Chimpanzee Sequencing and Analysis Consortium, led by Robert Waterston of the University of Washington School of Medicine and Eric Lander of the Broad Institute of MIT and Harvard. As with other major genome sequencing and analysis efforts, UCSC researchers provided bioinformatics expertise and developed a web-based browser and other valuable tools used to analyze the data. The UCSC Genome Browser (http://genome.ucsc.edu) is a highly popular web-based portal for the scientific exploration of genome sequences and related data. Pollard, who works with CBSE director David Haussler, has been involved in the chimp project since November 2003, when she began taking part in weekly conference calls with other members of the consortium. CBSE research scientist James Kent and software developer Kate Rosenbloom also contributed to the project and are coauthors on the paper. "We built a browser for the chimp genome and also added a couple of chimp tracks to the human genome browser to help with the comparative analysis," Kent said. Pollard said the Nature paper provides an overview of the consortium's initial findings and will be followed by additional papers focusing on specific questions. Pollard, for example, has been working to identify the regions of the human genome that have been evolving most rapidly. "That is the kind of question that could not be answered without looking at the genome of our closest relative," she said. by Tim Stephens