Ever since Darwin first published The Origin of the Species, scientists have been striving to identify a last universal common ancestor of all living species. Paleontological, biochemical, and genomic studies have produced conflicting versions of the evolutionary tree. Now a team of researchers, led by a professor at the State University of New York at Buffalo and including area high school students, has developed a novel method to search the vast archives of known gene sequences to identify and compare similar proteins across the many kingdoms of life. Using the comparisons to quantify the evolutionary closeness of different species, the researchers have identified Actinobacteria, a group of single membrane bacteria that include common soil and water life forms, as the base of the evolutionary tree. They will present their findings at the annual meeting of the American Crystallographic Association (ACA), held July 28 Aug. 1 in Boston, Mass.
"Today the gene banks are enormous. They contain more than 600,000 genes from the genomes of more than 6,000 species," says William Duax, a physical chemist and lead researcher on the team. However, many of the gene sequences, and the proteins they encode, are not systematically identified. Proteins that are structurally similar and perform the same function could be labeled with different numbers that obscure the fact that they belong to the same protein family. "Our first challenge is to make sure that we are comparing apples to apples and oranges to oranges," says Duax.
Duax and his team have developed efficient ways to search through the gene banks looking for all copies of the same family of protein. They concentrated their efforts on proteins that are found on the surface of cell components called ribosomes. The ribosomal proteins are among the most accurately identified proteins, and because they are not transferred between individuals independent of reproduction, are good candidates for traci
|Contact: Catherine Meyers|
American Institute of Physics