( associated with a SINE insertion in a g...)Scientists fetch useful information from dog genome publications

Sizing up skeletal variation

Portuguese Water Dogs (PWDs) were originally derived from two kennels that disagreed on an appropriate size standard for the breed. Although there were only a few animals in this initial gene pool, the considerable size differences among the founding individuals has made the PWD breed an excellent model for investigating the genetic basis of skeletal variation. Dr. Gordon Lark, Distinguished Professor Emeritus of Biology at the University of Utah, has been studying skeletal variation in the PWD breed and is the principal investigator on two papers appearing in the dog section of Genome Research.

In one of the publications, Lark's group reports forty QTL, or quantitative trait loci, that are responsible for determining skeletal size in dogs. A striking aspect of these loci is that they control functionally related skeletal traits. "For example," says Lark, "one of the QTL that we identified controls both pelvic size and metacarpal length, but the two traits are inversely correlated. This could represent a functional trade-off between high-speed, energy efficient running versus limb strength. Mammals specialized for running tend to exhibit large pelvic bones and relatively slender limbs."

In the second manuscript, Lark's team describes the genetic basis for sexual dimorphism, or size differences between male and female dogs. They attribute the differences to at least two interacting loci, one of which is located on the X chromosome. "Sexual dimorphism seems to have evolved as females became smaller than males due to natural selection for optimal size," Lark explains. "This is consistent with our finding that a variant on the X chromosome plays a role
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Source:Cold Spring Harbor Laboratory