The Role of Demographic History in Shaping Genetic Diversity in the Galapagos Penguin (Spheniscus mendiculus) and the Magellanic Penguin (Spheniscus magellanicus)
Year: 2017
Type: article
Abstract: 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 Galápagos 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 Galápagos 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 Galápagos 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 Galápagos penguin, a small fraction of the allelic and haplotype diversity detected in the Magellanic penguin.Despite the decreased genetic diversity in the Galápagos 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 iii polymorphism at this locus.Although Galápagos 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.project.I would also like to thank my committee members, Dr. Scott O. Rogers and Dr. Ron C. Woodruff, for their valuable input and patience.I owe lots of thanks to Dr. Hans Wildschutte for helping me troubleshoot lab work.Additional thanks go to Dr. P. Dee Boersma who coordinated Magellanic and Galápagos penguin sample collection.Special thanks go to my family and friends who have been supportive of
Author: Gabriella Arauco‐Shapiro
Institution: Bowling Green State University
Language: English
Subfield: Genetics
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2744925912