Twenty billion pieces of DNA in 100 small fish have opened the eyes of biologists studying evolution. After combining new technologies, researchers now know many of the genomic regions that allowed an ocean-dwelling fish to adapt to fresh water in several independently evolved populations.
The discovery -- made possible in a project funded by the National Science Foundation and National Institutes of Health -- involved threespine stickleback fish taken from three land-locked freshwater Alaskan lakes and two ocean populations. The work appears in the Feb. 26 issue of PLoS Genetics, an open-access online publication of the Public Library of Science.
A six-member UO team across two separate labs combined Illumina massively parallel sequencing with a specialized technology that they developed. They then compared the genomes of 20 fish each from Alaska's Bear Paw, Boot and Mud lakes, and 20 each from saltwater populations in Rabbit Slough and Resurrection Bay.
All sites are located along Alaska's south-central coast. Researchers found that all of the fish were closely related in most of their genomes, but with differences in very specific regions. Each fish contains 500 million base pairs of DNA. Researchers were surprised to find that across the independently derived populations very similar regions were identified, indicating that the same genes may be evolving when stickleback adaptation is repeated in different lakes. Researchers now are focusing efforts to understand which specific genes are involved in such adaptation.
The approach taken in the study, said William A. Cresko, professor of biology and member of the UO's Center for Ecology and Evolutionary Biology, could be applied to other organisms. "It would be fascinating to determine whether similar results would be found in studies of ocean-dwelling sockeye salmon and their freshwater counterparts the Kokanee, for example," he said. The findings, presented at pr
|Contact: Jim Barlow|
University of Oregon