Abstract Detail

Population Genetics/Genomics

Tamrakar, Rubin [1], Milligan, Brook [1], Buenemann, Michaela [1], Lehnhoff, Erik [1], Bailey, C. Donovan [2].

Genetic Variation Associated with Differential Response to Fire Among Populations of Cheatgrass (Poaceae, Bromus tectorum).

Bromus tectorum (cheatgrass) is an invasive grass from North Africa and Eurasia whose introduction and expansion in the US has particularly impacted rangeland systems across the Western USA. Previous studies found lower inter- but higher intra-population genetic variation in US populations than in native Old-World populations. This finding is consistent with the presence of genetic variation in US populations being derived from multiple founder events that may be contributing to invasive genotypes. In northern New Mexico, Bureau of Land Management land managers have observed populations of cheatgrass that differ in recovery after fire. Some populations demonstrate post-fire vigorous regrowth and even expansion while others do not. These observations suggest that NM population may contain genetic variation relevant to land management decisions. We have conducted a population genomic study using Angiosperms-353 genomic targets on 25 individuals for each of six populations from northern NM and 19 individuals from Red Bluff, Montana (as outgroups). Sequencing results obtained from enriched genomic libraries were used for locus reconstruction using HybPiper with an average of 31.3% reads on target. SNP variant calling was performed to generate a SNP map using VCFtools. Our preliminary analyses suggest the populations are highly inbred, which is consistent with the reproductive biology of this species and is also indicated by low heterozygosity. PCA and isolation by distancing analyses indicated genetic variation existed between populations. FastStructure ‘—chooseK’ indicated K=8 as the best fitting model in the preliminary results. FastStructure plot indicated considerable within population variation indicated by heterogeneity observed in percent ancestry of individual samples. Further comparison with fire history data in these six geographical sites will determine whether genetic variation correlates with observed responses to fire and the potential for unique adaptation between populations.

1 - New Mexico State University, 1780 E University Ave, Las Cruces, NM, 88003, United States
2 - New Mexico State University, Biology, Rm 120 Foster Hall (Stores), Dept Of Biology - New Mexico State University, Las Cruces, NM, 88003, United States

Keywords:
Bromus
HybPiper
FastStructure
Population.

Presentation Type: Oral Paper
Session: PGG1, Population Genetics and Genomics I
Location: /
Date: Tuesday, July 20th, 2021
Time: 4:00 PM(EDT)
Number: PGG1005
Abstract ID:1118
Candidate for Awards:Margaret Menzel Award