Neuroand Evolutionary Genetics of Migratory Behavior in Caribou ( R angifer tarandus)

Abstract

The migratory phenotype is a selection of morphological, sensory, and physiologically adaptive traits that are inherited together, allowing an individual animal to migrate. The genes that make up the molecular components of migration are currently unknown. Identification of these genes is important, because it will allow for a better understanding of the similarities and differences between the migratory syndromes of different species. Also, determining these genes will deepen the current scientific understanding of movement in general. With my senior thesis research, I determine more about the genetic basis of migration in North American caribou, by testing DNA extracted from caribou blood samples. While analyzing the data produced by genotypebysequencing of this DNA, I focus some of my attention on candidate genes implicated in migration by previous research. These include genes linked to exploratory behaviors, migration physiology, pathfinding mechanisms, and circannual clocks. A candidategene gene association study of this data was unsuccessful in that none of the candidate genes were found to meet a suggestive significance threshold level. However, the results of a genomewide association study of this data suggests that particular genomic regions linked to neurological development have undergone strong differential selection in migratory and nonmigratory populations. The results of the gene enrichment analysis portion of this project indicate that differences in development of the cranial nerve, synapses, dendritic spines, as well as the temperaturesensing biological processes, help to compose the migratory phenotype in woodland caribou.