Another contribution from Michael Kubisch.
Ever wondered why your rat terrier looks so different from your neighbor’s mastiff? Well, eons of selective breeding, of course, which have resulted in genetic differences between these two and other dog breeds. Man’s best friend was undoubtedly among the very first animals to be domesticated, although the huge variety of breeds found today is probably a much more recent phenomenon. Which part of the dog genome, or more pertinently which genes, were involved in generating this diversity remains largely a mystery — but one that many geneticists would like to solve.
A first glimpse has now been provided by a group of scientists who compared genomic data from dogs belonging to ten different breeds using what is called single-nucleotide polymorphisms or SNPs for short. SNPS are very helpful because the presence of a particular SNP sometimes is indicative of the presence of a specific allele at a nearby gene. Similarly, if there are SNPs that differ between two dog breeds it is possible that nearby genes may be different as well and that those genes may have played a role in what sets these breeds apart.
The study revealed 150 areas of the dog genome containing more than 1000 candidate genes that appeared highly variable between those breeds that were examined. Not surprisingly perhaps, several of these genes are known to determine things like coat color, size, skeletal morphology and behavior. However, interestingly, several candidates included genes that are known to act as regulators of other genes, suggesting that some evolutionary changes are not the result of variant alleles of genes but changes in how these genes are controlled. More interesting insights are sure to follow.
