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Population Genetic Analysis of Two Eastern North-American Bats

Aguilar Cabezas, Juan Pablo
http://orcid.org/0000-0002-5808-4185
http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1660776832779526

Abstract Details

2022, Doctor of Philosophy (PhD), Ohio University, Biological Sciences (Arts and Sciences).
Bats are the second most numerous mammalian taxon and provide critical human ecosystem services such as pollination and pest control. Globally, they are threatened by multiple factors such as habitat degradation, contamination, and emerging diseases such as white-nose syndrome (WNS). This disease is caused by a fungus, which was introduced from Europe to North America, and has killed millions of bats, with some species showing precipitous declines in abundance. A result of such population decline is the loss of genetic diversity, and hence the loss of adaptive potential. The goal of this dissertation is to use genetic data to further understand the population ecology of two bat species that are differentially affected by white-nose syndrome, the big brown bat, Eptesicus fuscus, and the northern myotis, Myotis septentrionalis. The first species doesn’t show symptoms of the disease and is potentially playing a significant role in spreading the pathogen. I estimated the population genetic structure and estimated genetic differentiation among eight states using data from the cytochrome-b gene. I found moderate population structure, suggesting that dispersal and gene flow is occurring mostly within states, but movement across long-distances are possible as suggested by a moderate fixation index. In addition, I inferred population size trends and found that the big brown bat populations are declining, an unexpected result for an abundant species. The second species that I studied was the northern myotis. This species has shown a drastic decline in winter surveys, with declines of about 95%. To investigate recent population size changes, I first assembled the genome using short and long-read data. The final assembly was largely contiguous, composed of 92 fragments, and had a high completeness, with a BUSCO Score of 96.1% of the mammalia orthologs core genes. The genome annotation was very complete as well, with 55075 genes and a BUSCO SCORE of 98.5%. It also indicated that 22.66% of the genome is composed of repetitive sequences. Then, I calculated and compared genome-wide diversity between individuals collected in counties with and without WNS detection and estimated recent fluctuations in population size. I found that individuals collected in counties without WNS detection harbored more genetic diversity measured as insertion-deletion polymorphisms and singletons but had less heterozygosity than those collected in counties with WNS. I speculate that WNS is another example of a case of pathogen-driven balancing selection, where individuals with higher heterozygosity have higher fitness. The most dramatic results were derived from the demographic reconstruction of recent history: I found that populations of northern myotis suffered a recent and very abrupt decline in population size, more than that suggested by winter surveys. This study highlights the importance of using genetic diversity to characterize the demographic response of species to threats and to determine the conservation status of elusive species such as the northern myotis.
Joseph S. Johnson (Advisor)
Donald B. Miles (Advisor)
Andor J. Kiss (Committee Member)
Shawn R. Kuchta (Committee Member)
Harvey E. Ballard, Jr. (Committee Member)
127 p.
Conservation; Ecology; Genetics; Wildlife Conservation; Zoology
bats; ecology; conservation genetics; demography; population genetics; selection; evolutionary genetics; genomics; disease ecology; white-nose syndrome

Recommended Citations

Citations

  • Aguilar Cabezas, J. P. (2022). Population Genetic Analysis of Two Eastern North-American Bats [Doctoral dissertation, Ohio University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1660776832779526

    APA Style (7th edition)

  • Aguilar Cabezas, Juan Pablo. Population Genetic Analysis of Two Eastern North-American Bats. 2022. Ohio University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1660776832779526.

    MLA Style (8th edition)

  • Aguilar Cabezas, Juan Pablo. "Population Genetic Analysis of Two Eastern North-American Bats." Doctoral dissertation, Ohio University, 2022. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1660776832779526

    Chicago Manual of Style (17th edition)

ohiou1660776832779526
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This open access ETD is published by Ohio University and OhioLINK.