Conservation Genomics: Utilizing Genetic and Transcriptomic Sequencing for Effective Conservation Management of Astragalus osterhoutii

Astragalus osterhoutii M.E. Jones (Fabaceae) is a federally listed, rare, endemic species restricted to seleniferous soils in Grand County, CO (Anderson, 1989). This research utilized both RADseq and RNAseq to generate neutral and adaptive genomic datasets. Neutral data analysis aimed to determine i) the genetic diversity of A. osterhoutii and each of its populations level, ii) how genetic structure is partitioned across the species range, and iii) the closest relative to A. osterhoutii. Analysis of adaptive, RNAseq data aimed to identify i) differentially expressed genes, ii) if patterns of expression are similar to neutral data, and iii) differences in Se hyperaccumulation genes among populations. Neutral data found a relatively low level of species genetic diversity, with similar levels seen between populations. Neutral data supported A. grayi and A. nelsonianus as closest relatives. Both datasets supported a geographic division of genomic makeup between eastern and western populations, with a finer split into three groups following the three main drainages, Muddy Creek, Troublesome Creek, and Rock Creek except for the FO population, which was distinct from other Muddy Creek populations. RNAseq data found Se genes to be generally downregulated in the western populations compared to eastern populations and suggests adaptive divergence between drainages. Four distinct conservation management units are recommended from combined results, i) Western ii) Field Office, iii) Troublesome Creek, and iv) Eastern. Establishing monitoring plots for at least one population within each of the management units is also recommended. A. osterhoutii should remained listed as a federally protected, endangered species