Biology ETDs

Publication Date

Summer 7-15-2024

Abstract

Mitochondrial introgression has potential consequences for physiology and adaptation, but its causes are poorly understood. The Audubon’s Warbler (AUWA; Setophaga coronata auduboni) provides a case study to examine those causes as mitochondrial introgression has swept through part of the range. The northern mitochondrial genome (mtDNA) introgressed from the Myrtle Warbler (MYWA; S. c. coronata) and is 4% divergent from the southern mtDNA. Incomplete introgression suggests discordant AUWAs conferred a selective advantage in the north; it was hypothesized that energetic demands associated with migration formed this advantage. We tested two hypotheses to explain partial introgression and the mtDNA distribution by testing for chain versus leapfrog migration; only leapfrog supports migration-adapted mitochondria (MAM). Second, we asked whether environmental variation influenced the distribution by testing if local climate predicted mtDNA. Our findings contradicted MAM and provided moderate support for environmental association. The evidence implicates spatially varying, climate-mediated selection in mtDNA introgression.

Project Sponsors

NSF GRFP, NSF MRT, UNM Biology

Keywords

mitochondria, evolution, birds, mitonuclear coevolution

Document Type

Thesis

Degree Name

Biology

Level of Degree

Masters

Department Name

UNM Biology Department

First Committee Member (Chair)

Christopher C. Witt

Second Committee Member

Lisa N. Barrow

Third Committee Member

David P. L. Toews

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