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Resolving the Xenarthran Phylogeny Using Nuclear Loci

Xenarthra form the least diversified major clade of placental mammals, being comprised of 31 described species of sloth, armadillo, and anteater. The past decade has seen a growth in the amount of xenarthran genetic data available, including the recent publication of a phylogenetic framework based on mitochondrial genomes, but more is required to aid in conservation assessments and to elucidate the evolutionary history of this unique order. We aimed to expand upon this by generating a framework based on nuclear genes.

Using molecular baits, we enriched nuclear DNA from all extant and a selection of extinct ancient Xenarthrans for 74 phenotypically relevant genes. We aim to build phylogenetic trees based on each successfully enriched loci. Comparing trees against the previous mitochondrial framework will provide a measure of robustness. By seeing how estimated divergence times and rates vary across nuclear genes, we were able to examine how particular xenarthran phenotypes were selected upon in different points of their evolutionary history. While the sequencing of certain genes and species encountered mixed success rates, we have a solid framework for further study and can confirm that nuclear and mitochondrial information yields very similar evolutionary histories. / Thesis / Master of Science (MSc) / Xenarthrans - sloths, armadillos, and anteaters - have a long and complicated evolutionary history. In recent years a growth of new genetic information has made it easier to answer questions about their relation to each other and to other species. By examining many new gene sequences across all living Xenarthra, plus some extinct species, we aim to bolster our understanding of these relationships and the importance of particular traits.

Identiferoai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/21456
Date January 2017
CreatorsHughes, Jonathan
ContributorsPoinar, Hendrik, Golding, Brian, Biology
Source SetsMcMaster University
LanguageEnglish
Detected LanguageEnglish
TypeThesis

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