Genomics of physiological adaptations of two milkweed species (Asclepias) in their hybrid zone

Abstract

Speciation is the source of diversity on the planet, but the genomic mechanisms that lead to the reproductive isolating barriers between populations that cause speciation are not well understood. Here we are studying the genomic differentiation between two species of milkweed that grow in the Western (Asclepias speciosa) and Eastern United States (A. syrica). In addition to different geographic locations, these species have diverged in a number of important phenotypes, including: production of secondary metabolites, flower morphology, and drought resistance. In the central US, these species have come into secondary contact and sometimes form hybrids in the wild. We are interested in quantifying the amount of gene flow between these species and identifying genomic locations that may be indicative of local adaptation within populations and reproductive isolation between species.To compare these species of milkweed, we isolated DNA from A. speciousa, A. syrica, and individuals that displays intermediate phenotypes from the hybridization zone. We extracted and isolated genomic DNA and sequenced their genomes with Oxford Nanopore technology. With the aligned genomes, we will be able to compare polymorphisms in these species and begin to quantify the amount of gene flow between them. We will also identify polymorphisms in candidate genes and pathways that may have led to ecological specialization between these species.Support or Funding InformationSouth Dakota EPSCoR IIA‐1355423South Dakota BRIN P20GM 103443This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.