Abstract Detail

Hybrids and Hybridization

Grossfurthner, Lukas P. [1], Hohenlohe, Paul [2], Waits, Lisette [3], Richardson, Bryce [4].

Hybridization, polyploidization and their effect on phenotype in Big Sagebrush (Artemisia tridentata).

Ecotones, the transitional zone between two or more habitats, are evolutionary and ecologically important regions, as they form a bridge that allows the exchange of organisms and the contact of related species. The latter often leads to hybridization and introgression, that is the exchange of genetic material between two different lineages and thus, shifts allele frequencies or generates new genotypes and phenotypes. Artemisia tridentata (big sagebrush) is an excellent study system to address the effect of ecotones on species, because it is a landscape dominating plant in the western United States, occupies multiple distinct ecological niches and exhibits diploid and tetraploid cytotypes, which led to the recognition of three widely accepted subspecies. These subspecies are ecologically, chemically and cytologically separated, but are known to hybridize when they co-occur. Here, we sampled five spatially and ecologically differing ecotones across the distribution range of A. tridentata and propose to identify and quantify gene flow between subspecies at different ploidy levels as well as the genomic and ecological consequences. Applying ddRAD-sequencing on individuals with ploidy assessed using flow-cytometry and calibrated via chromosome counts, we (i) aim to identify if, to what extent and at which ploidy level gene flow occurs between subspecies. Furthermore, we test (ii) whether gene flow is geographically restricted and admixed individuals only occur between the parental habitats or whether polyploidization lowers the cost of hybridization and serves as a conduit for gene flow between populations. We further test (iii) if ploidy variation is a mechanism of speciation that results in a reduction of gene flow between heteroploid populations, whether there is backcrossing to either parent or whether we are able to detect differentially introgressed genomic regions as indicator for local adaptation.

1 - University of Idaho, Bioinformatics and Computational Biology Graduate Program, Moscow, ID, USA
2 - University Of Idaho, Initiative for Bioinformatics and Evolutionary Studies, Department of Biological Sciences, Moscow, ID, USA
3 - University Of Idaho, Department of Fish and Wildlife Resources, Moscow, ID, USA
4 - USDA Forest Service, Rocky Mountain Research Station, Moscow, ID, USA

Keywords:
Artemisia tridentata
hybridization
polyploidy
heteroploid dataset
ddradseq.

Presentation Type: Oral Paper
Number: HH2001
Abstract ID:790
Candidate for Awards:Margaret Menzel Award