Abstract Detail

Recent Topics Posters

Hamlin, Jennafer [1], Arnold, Michael [1].

What drives genetic and phenotypic divergence for Iris hexagona?

Given that landscapes are heterogeneous in nature, the consequences of these fragmented landscapes include small isolated populations. Within these small populations divergence at both genetic and morphological level can occur. However, genetic and morphological divergence across populations could be the product of limited dispersal, also known as isolation-by-distance, or adaptation. Within plants, selection on various floral morphologies has been well documented and shown to be influenced by both abiotic and biotic factors. We are examining the relative roles of isolation-by-distance and isolation-by-adaptation in promoting morphological divergence within a species, Iris hexagona, a member of the species complex known as the “Louisiana irises.” Using a genotyping-by-sequencing approach, we sampled a large number of single nucleotide polymorphisms across I. hexagona genome. We generated a panel of 750 SNPs and used population genetic analyses to test whether patterns of neutral genetic divergence across I. hexagona populations are better explained by isolation-by-distance or isolation-by-adaptation. We then compared the amount of divergence among populations at neutral and non-neutral SNPs with the magnitude of phenotypic differences in vegetative and floral traits. We show that high levels of genetic differentiation exist for non-neutral SNPs compared to neutral SNPs. There is not an overall relationship between pairwise genetic distance, computed for neutral SNPs, and geographic distance, which would have been indicative of isolation-by-distance. Additionally, we show that non-neutral genetic differentiation is correlated with both geographic distance and morphological divergence. For I. hexgaona, it appears that both neutral and selective forces are at play in generating divergence.

1 - University of Georgia, Genetics, 120 E. Green St. , Davsion Life Sciences Building, Athens, GA, 30602, USA

Keywords:
population genetics
local adaptation
Iris hexagona
neutral processes.

Presentation Type: Recent Topics Poster
Session: P
Location: /
Date: Monday, July 28th, 2014
Time: 5:30 PM
Number: PRT004
Abstract ID:1241
Candidate for Awards:None