Abstract Detail

Population Genetics/Genomics

Faske, Trevor [1], Agneray, Alison [2], Jahner, Joshua [2], Richardson, Bryce [3], Leger, Elizabeth [1], Parchman, Thomas [4].

Range-wide predictors of landscape genetic structure within a foundational plant of the Great Basin.

Understanding how evolutionary history, environment, and geographic variation shape spatial genetic structure is critical for interpreting phenotypic variation, population divergence, and speciation. Widely distributed plants of the western North America occupy striking environmental gradients due to the extreme topographic complexity of the region and often have complex evolutionary histories stemming from distinct refugia during recent glacial periods. Rubber rabbitbrush (Ericameria nauseosa) is a foundational western North American shrub species and is of restoration value within sagebrush steppe communities. Additionally, it is host to a diverse range of herbivores and is strikingly phenotypically diverse; represented by two described subspecies -consimilis and nauseosa. Here, we describe range-wide patterns of landscape genetic variation in E. nauseosa in association with its geographic, environmental, and evolutionary history. We used reduced representation sequencing (ddRADseq) to describe genetic structuring within and among the two E. nauseosa subspecies and patterns leading to reproductive isolation/hybridization. Despite substantial geographic overlap, the two subspecies exhibit consistent genetic differentiation across the range with few populations exhibiting limited hybridization, suggesting reproductive isolation persists. Differentiation within subspecies is less pronounced but population structure is clear at remarkably fine spatial scales and consistent with patterns of isolation-by-distance (IBD) and isolation-by-environment (IBE). Environmental variation associated with precipitation seasonality, actual evapo-transpiration, and annual temperature were drivers of genetic partitioning among the two subspecies. Additionally, proximity to major ecotones predicted hybridization, which is consistent with classic predictions of suture zones. In conclusion, subspecies within the E. nauseosa complex have unique evolutionary histories associated with landscape variation. Phenotypic differentiation among the subspecies is maintained despite mostly overlapping distributions, suggesting ecological or intrinsic mechanisms of reproductive isolation and hybridization can be predicted by both environmental variation and proximity to ecotone.

1 - University Of Nevada, Reno, Biology (0314), 1664 N. Virginia Street, Reno, NV, 89557, United States
2 - University of Nevada, Reno, 1664 N. Virginia Street, Reno, Nevada, 89557, United States
3 - USGS Forest Service
4 - University Of Nevada Reno, Biology, 1664 North Virginia Street, Reno, NV, 89557, United States

Keywords:
Landscape genetics
hybridization
Genetic-environment association.

Presentation Type: Oral Paper
Session: PGG4, Population Genetics and Genomics IV
Location: /
Date: Wednesday, July 21st, 2021
Time: 4:30 PM(EDT)
Number: PGG4007
Abstract ID:127
Candidate for Awards:Margaret Menzel Award