Patterns of genetic variation among various Beringian birds

Abstract

Every animal has two different sets of genes, the mitochondrial genome and the nuclear genome. They are inherited independently of each other and can have dissimilar evolutionary histories. For this thesis, I examined the correlation of the mitochondrial (using direct sequencing of mitochondrial DNA) and nuclear (using a fragment-based technique, AFLPs) evolutionary histories in Beringian birds. The first study looked at relationships among a within-Beringia radiation of birds, the Aethia auklets. I was able to infer a resolved phylogeny using mitochondrial DNA, but found a polytomy using nuclear DNA. The lack of correlation between the genomes is either the result of incomplete lineage sorting or reflects the fact that AFLPs may not be an appropriate technique to survey nuclear diversity at this level of divergence. In the second study, I examined the correlation between taxonomic status, mitochondrial divergence, and nuclear divergence among nine lineages of trans-Beringian birds. I found no relationship between any of the three variables, suggesting that trans-Beringian birds have complex and discordant genetic and phenotypic histories.