Abstract Detail

Population Genetics/Genomics

Zlonis, Katharine [1], Etterson, Julie [2], Gross, Briana [3].

Genetic structure, natural selection, and hybridization in populations of the rare arctic relict Euphrasia hudsoniana (Orobanchaceae) and its invasive congener Euphrasia stricta.

In North America, relict arctic plant populations from the last glacial maximum persist in disjunct locations south of their normal range. These fringe populations may be particularly threatened by stressors associated with climate change, including increased temperature, decreased water availability, and increased competition with invasive species. In Minnesota, several arctic relicts of conservation concern are restricted to the rocky coast immediately adjacent Lake Superior, including Euphrasia hudsoniana. We used GBS (genotyping-by-sequencing) and collected phenotypic data to assess genetic structure and natural selection among five populations of E. hudsoniana along the north shore of Lake Superior. We also examined whether there is evidence for hybridization between E. hudsoniana and its invasive congener, E. stricta. Population genetic analyses show differentiation among all populations on the north shore, especially two central populations that fall into a separate cluster based on STRUCTURE analysis. We found limited gene flow from E. stricta to E. hudsoniana, but observed greater gene flow in the opposite direction. Significant selection gradients, indicating direct selection, were observed for 1-3 traits per population; however, significant selection differentials, due to indirect selection on correlated traits, were observed for all or most traits at each site in both years that phenotype data were collected. Taken together, weak genetic structure observed for E. hudsoniana populations and selection on most traits in the same direction among populations, suggest that climate change poses a similar risk to all populations in Minnesota. Monitoring of these populations should continue to assess whether hybridization with invasive E. stricta is a burgeoning threat.

1 - University of Minnesota Duluth, Department of Biology, 1035 Kirby Drive, Duluth, MN, 55812, USA
2 - University Of Minnesota Duluth, 207 Swenson Science Building, 1110 Kirby Drive, 207 Swenson Science Building, 1035 Kirby Drive, Duluth, MN, 55812, United States
3 - University Of Minnesota Duluth, Department Of Biology, 207 Swenson Science Building, 1035 Kirby Drive, Duluth, MN, 55812, United States

Keywords:
arctic disjunct
Climate change
Polyploid
invasive
Hybridization
population genetics.

Presentation Type: Oral Paper
Session: 38, Population Genetics and Genomics I
Location: 101/Mayo Civic Center
Date: Wednesday, July 25th, 2018
Time: 9:30 AM
Number: 38007
Abstract ID:109
Candidate for Awards:None