Evolution of coat color variation and molecular genetics of Yellowstone wolves

Research contact: Rena Schweizer

Introduction

A central goal in evolutionary biology is to relate variation in phenotypes (the physical, observable characteristic of an organism) to the underlying genotypes (the genetic or DNA characteristic of an organism) and to illuminate molecular mechanisms for adaptation. Traits that improve reproductive success or survivorship tend to increase in frequency over time (positive selection) and generate distinct patterns of genetic variation.

Our research focuses on understanding positive selection at the K locus, a gene responsible for black coat color in wolves and domestic dogs. The KB allele is a 3 base pair (bp) deletion that confers a dominantly inherited black coat color, whereas the wild-type Ky allele confers a gray coat color in homozygotes1. A previous study suggests that the KB allele was introduced into the genome of North American wolves from the domestic dog via interbreeding, and then underwent positive selection1. This study used a relatively small data set and, as a result, could not fully address many details of the K locus1.

Methods

We have designed a set of sequence capture probes ("capture array") to sequence thousands of regions of the wolf genome, including candidate genes related to morphology and physiology for exploring selection among wolf ecotypes. About 200 of our samples are Yellowstone wolves, including some of the original founders as well as many more recent wolves. We are using the Yellowstone wolf genealogy to make specific genetic estimates of recombination events and mutation rate, as well as to understand the inheritance of different genes causing varying morphology and behavior of these wolves. The substantial data and sampling done by researchers with the Wolf Project will be very important to our work.

References

1. Anderson, TM, Vonholdt, B M, Candille, SI et al. (2009) Science 323:1339-43.