I’ve mentioned the emergence of the dog as a model organism in genetics– the resources available now have made all sorts of questions easy (well, not easy, but comparatively easy) to answer. One such question: what makes certain breeds of dog black? The answer is now available online at Science: a small deletion in a gene called CDB103.
The gene is interesting because it encodes a novel ligand for MC1R, mutations in which cause red hair in humans (and lighter fur in mammoths). The melanocortin pathway seems to be polymorphic in all mammals studied, perhaps due to similar selective pressures on coat/hair color.
The authors have a neat picture of mice they turned black by inserting copies of the variant allele, which raises the question: can any dog breed be turned black? And if so, how much will people pay for it?