Adaptation and Speciation in Macaques

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Laurie Stevison, Ph.D.
Department of Biological Sciences
Auburn University

Laurie Stevison1, Zachary Szpiech1, Nick Bailey1, Taylor Novak1, Damien Waits1, Ben Evans2, and Jeff Wall3
1Auburn University, 2McMaster University, 3University of California San Francisco

Macaques are a speciose group of old world monkeys that are widely distributed and experience a variety of habitats, leading to adaption in phenotypic traits such as tail length, body size, coat color, etc. Further, they have many examples of complex speciation. Rhesus macaques are the most commonly used non-human primates in biomedical research and there are plentiful genomic resources and genetic variation to address major evolutionary patterns such as adaptation and speciation. For this seminar, I will highlight three unpublished projects in my lab at Auburn University: 1) an investigation into the proposed hybrid species origin of the bear macaque; 2) an examination for mitonuclear incompatibilities in the evolution of the bear macaque; and 3) a test for adaptation to high altitude in wild rhesus macaques.

The bear macaque is proposed to have evolved via ancient hybridization between the Fascicularis and Sinica species groups. It is reproductively isolated from parental species groups via divergent genital morphology. We analyzed gene flow (fdM) using WGS from 5 species, including the bear macaque (3), and Sinica (3) and Fascicularis (4) species groups. We compared phylogenetic relationships across the genome (Twisst). The intersection of these methods was highly concordant, identifying 608 genes in the bear macaque introgressed from the Sinica group and 365 from the Fascicularis group. Our analysis reveals extensive gene flow, with reproductive isolation potentially explained by gene flow of a gene overlapping a major baculum QTL.

We also found significantly different levels of introgression between the autosomes, the X, and the mitochondria. Therefore, we investigated the potential for genomic conflict between the mitochondrial and nuclear genomes. We compared gene flow (fdM), differentiation (DXY, FST), and natural selection (dN/dS) across 145 genes encoded in the nuclear genome that interact with the mitochondria (NMTs). So far, our results are inconclusive for evidence of mitonuclear incompatibilities driving evolution in the bear macaque.

Finally, we analyzed whole genomes of 23 high and 22 low altitude wild rhesus macaques. We scanned for local adaptation between populations (XP-EHH) and found strong signatures of recent selection in the high altitude population at or near 205 known genes and several unannotated regions. We found signals for adaptation in EGLN1, a common target for high altitude adaptation, and significant enrichment for genes involved in oxygen homeostasis.

Stevison grew up just outside of New Orleans, LA. She earned a BS in Biophysics, a master's degree in the Ecology and Evolutionary Biology (EEB) Department at Rice University and completed her Ph.D. at Duke University. Her research there was broadly focused on the causes and consequences of recombination rate variation in Drosophila. In addition to building a dense recombination map in Drosophila persimilis and showing an indirect effect of male genotype on variation in female recombination, she worked with collaborators to perform one of the first population genomic studies using low-coverage whole-genome next generation sequencing, which answered long standing evolutionary questions in a classic model system for studying chromosomal inversions, Drosophila pseudoobscura and D. persimilis. Later, she performed a comprehensive analysis of inversions within and between species on their role in speciation in this system.
After a postdoc at UC San Francisco she joined the faculty of Auburn University where she is currently an Assistant Professor in the Department of Biological Sciences. The Stevison lab works on projects related to speciation, hybridization and evolution of recombination rates.

Host: Soojin Yi, Ph.D.


  • Workflow Status:Published
  • Created By:Jasmine Martin
  • Created:09/20/2019
  • Modified By:Jasmine Martin
  • Modified:10/22/2019