Meeting Abstract
The hoary marmot (Marmota caligata) has a broad distribution in North America, but melanistic (black) morphs are known only in and around Glacier Bay National Park in SE Alaska. The adaptive role of melanism in hoary marmots is unknown. Melanistic marmots are more visually conspicuous than their wildtype counterparts, and we hypothesize they are more vulnerable to predation. However, black pelage may offer a thermoregulatory benefit as it should absorb more heat and reduce the need to sunbathe. Further, hairs dense with melanin may better resist microbial degradation, as the pigment melanin is known to confer microbial resistance. To explain the adaptive significance of melanism in hoary marmots, we first sought to explain the genetic underpinnings of the trait. We have collected six melanistic and two wild-type hoary marmots from the Chilkat Mountains outside Glacier Bay, collecting RNA-quality skin punches from each pelage color present on each marmot. I will present preliminary DNA sequence data of genes known to control pelage color in mammals from these individuals, as well as qPCR results demonstrating how these genes are expressed in skin growing hairs of different color. These will be compared to the same sequences from the hoary marmot’s closest living relative, the critically endangered Vancouver Island marmot (M. vancouverensis), which is completely fixed for melanism over most of its body. I will also present scanning electron micrographs of individual marmot hairs of each color, which we examined for evidence of differential microbial degradation using methods from human hair forensics.
