| Abstract Detail
Speciation Mechanisms in Plants Koski, Matthew [1], Busch, Jeremiah [2], Galloway, Laura [3]. Dynamic colonization history drives geographic patterns of reproductive incompatibility. Fitness breakdowns in F2 hybrids between populations indicate the accumulation of Dobzhansky-Muller incompatibilities, a critical initial step towards the evolution of distinct species. In plants of eastern North America, genetic divergence between populations often exhibits a Mississippi River Discontinuity (MRD), consistent with its role as a barrier to gene flow. Population genetic structure is also often shaped by post-glacial migration from refugia on the Gulf Coast. In Campanula americana, recent work supports its persistence in glacial refugia in the Deep South and the Southern Appalachians during the Pleistocene. Populations far from these locales were founded by a colonization wave originating from the Appalachian refugium, with subsequent spread from a staging ground west of the Mississippi River. We explored the role of the MRD in shaping F2 reproductive isolation in C. americana by generating F2 hybrids between populations across the MRD, and contextualizing patterns of hybrid breakdown with population genomic data and models of historical colonization. Breakdown was most pronounced between populations near the Deep South refugium and exhibited asymmetry, with stronger breakdown when populations east of the MRD were maternal parents. For recently colonized populations sharing ancestry from the Appalachian Refugium, however, breakdown was weak. Results highlight that the dynamic histories of populations spanning geographic barriers generate differential accumulation of genomic incompatibilities, and thus speciation potential.
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1 - Clemson University, Biological Sciences, 134 Long Hall, Clemson, SC, 29634, United States
2 - Washington State University, School Of Biological Sciences, PO Box 641020, Pullman, WA, 99164, United States
3 - University Of Virginia, Biology Department, P.O. Box 400328, Charlottesville, VA, 22904, United States
Keywords:
hybrid breakdown
Reproductive Isolation
glacial refugia
colonization
phylogeography.
Presentation Type: Colloquium Presentations
Session: C09, Speciation Mechanisms in Plants
Location: /
Date: Thursday, July 22nd, 2021
Time: 4:15 PM(EDT)
Number: C09011
Abstract ID:105
Candidate for Awards:None |
