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The Role of Demographic History in Shaping Genetic Diversity in the Galapagos Penguin (Spheniscus mendiculus) and the Magellanic Penguin (Spheniscus magellanicus)

Arauco-Shapiro, Gabriella
http://orcid.org/0000-0003-3834-3407
http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1494588279161113

Abstract Details

2017, Master of Science (MS), Bowling Green State University, Biological Sciences.
Although several studies have documented the genetic effects of demographic bottlenecks on the overall genetic diversity of natural populations, there is conflicting evidence on the potential roles that genetic drift and selection may play in driving changes in genetic variation at neutral and adaptive loci. In this study, genetic variation at neutral microsatellite and mtDNA loci in conjunction with an adaptive MHC class II locus was analyzed in the Galapagos penguin (Spheniscus mendiculus), a species that has undergone serial demographic bottlenecks associated with El Niño events through its evolutionary history. Levels of variation in the Galapagos penguin were compared to those of its congener, the Magellanic penguin (Spheniscus magellanicus), a closely related species that has consistently maintained a large populations size, and thus was used a non-bottlenecked control. The comparison of neutral and adaptive markers in these two demographically distinct species allowed assessment of the potential role of balancing selection in maintaining levels of MHC variation during bottleneck events. This analysis highlights the dearth of genetic diversity at all loci in the Galapagos penguin compared to the Magellanic penguin due to its history of demographic bottlenecks. There were two MHC alleles, one mtDNA haplotype, and six alleles across all five microsatellite loci assessed in the Galapagos penguin, a small fraction of the allelic and haplotype diversity detected in the Magellanic penguin. Despite the decreased genetic diversity in the Galapagos penguin, results revealed signals of current balancing selection at the MHC, which suggest that selection can counteract the effects of genetic drift through bottleneck events, maintaining current levels of polymorphism at this locus. Although Galapagos penguin populations have persisted for a long time, increased frequency of El Niño events due to global climate change, as well as the low diversity exhibited at immunological loci, may put this species at further risk of extinction.
Juan Bouzat, PhD (Advisor)
Scott Rogers, PhD (Committee Member)
Ronny Woodruff, PhD (Committee Member)
56 p.
Biology; Conservation; Genetics
demographic bottlenecks; genetic drift; balancing selection; major histocompatibility complex

Recommended Citations

Citations

  • Arauco-Shapiro, G. (2017). The Role of Demographic History in Shaping Genetic Diversity in the Galapagos Penguin (Spheniscus mendiculus) and the Magellanic Penguin (Spheniscus magellanicus) [Master's thesis, Bowling Green State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1494588279161113

    APA Style (7th edition)

  • Arauco-Shapiro, Gabriella. The Role of Demographic History in Shaping Genetic Diversity in the Galapagos Penguin (Spheniscus mendiculus) and the Magellanic Penguin (Spheniscus magellanicus). 2017. Bowling Green State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1494588279161113.

    MLA Style (8th edition)

  • Arauco-Shapiro, Gabriella. "The Role of Demographic History in Shaping Genetic Diversity in the Galapagos Penguin (Spheniscus mendiculus) and the Magellanic Penguin (Spheniscus magellanicus)." Master's thesis, Bowling Green State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1494588279161113

    Chicago Manual of Style (17th edition)

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This open access ETD is published by Bowling Green State University and OhioLINK.