In the December issue of Genome Research--a special issue devoted to dog genomes--TIGR researchers Ewen Kirkness and Wei Wang compared the genome sequences of two dogs, a standard poodle and a boxer. Finding key genetic differences between the two dogs, the researchers went on to compare those telltale genetic variations in the genomes from nine additional dog breeds--beagle, Labrador retriever, German shepherd, Italian greyhound, English shepherd, Bedlington terrier, Portuguese water dog, Alaskan malamute, and rottweiler--and five genomes of wild canids (four types of wolves and a coyote).
"This work demonstrates a significant amount of variation that you can see between individual dogs at the genomic level," says Kirkness, lead investigator of the project, funded by TIGR. "That variation can now be exploited to study the differences between dogs, their diseases, development and behaviors." More broadly, Kirkness adds, the comparisons illustrate evolutionary influences that can shape mammalian genomes.
In the study, the scientists first compared the two most complete canine genomes available. Those genomes belong to Shadow, a standard poodle whose genome was published by TIGR in 2003, and Tasha, a boxer sequenced by the Broad Institute of Cambridge, Massachusetts, in 2004.
To compare Shadow's and Tasha's genomes, the researchers tracked short interspersed elements (SINEs)--stretches of DNA that occur randomly in the genomes of many organisms. SINEs are inserted near or within genes, often turning the expression of those genes up, down or even off. The scientists found that the poodle and boxer differe
Contact: Kathryn Brown
The Institute for Genomic Research