As I’m sure you all know, February 12th is Darwin Day, a day to celebrate science and the insight into humanity that the scientific method in general, and Darwin’s studies in particular, have brought about.
In honor of the day, check out this article on dog evolution — scientists have sequenced the DNA of ten different dog breeds and are discovering exactly what mutations our selective breeding has brought about, including what puts the wrinkles on Shar-peis.
Dogs (Canis lupus familiaris) were first domesticated around 14,000 years ago, long before the field of genetics even existed, though most dog breeds were developed in the last few centuries. As humans bred dogs for features such as shorter legs or a docile temperament, they were actually tinkering with genes, while influencing the selection and expression of dog genes.
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Previous studies of dog genes have paired genes to their resulting phenotype — for example, the stumpy legs of Dachshunds — but these studies started with the physical trait and looked for the corresponding gene or genes that coded for it. Akey’s study instead compared gene regions that showed signs of change between breeds and looked for physical traits that might correspond to those changes.
The team found 155 distinct genetic locations that showed evidence of tampering from breeding.
Artificial selection directly proves evolution. The fact that we can artificially select for traits just like nature can naturally select for them in what amounts to an environmental arms race, and that these traits build upon themselves over time, is self-evident. If we keep selecting chihuahuas away from great danes, we could speciate them. In fact, they’re pretty close to speciated already, with the size differential making for mating to be terribly difficult. And they all come from wild dogs, which humans once domesticated.
Darwin suspected all of this and wrote it all out in book form before anyone else was able to articulate it, short of Wallace who barely managed a few pages. But the idea had been around for some time before, and those people actively engaged in artificial selection actually figured out a lot of the mechanisms behind it. It’s been staring us in the face for as long as we’ve existed, and we only figured it out 150 years ago. It boggles the mind.