Putative drought-adapted SNPs increase in frequency during severe drought
Authors: Daniel Anstett 1,2; Julia Anstett 2; Dylan Moxley 2; Mojtaba Jahani 2; Kaichi Huang 2; Marco Todesco 2; Rebecca Jordan 3; Loren Rieseberg 2; Amy Angert 2
Affiliations: 1) Michigan State University, Lansing, MI; 2) University of British Columbia, Vancouver, BC; 3) CSIRO, Land and Water, Sandy Bay, Tasmania, Australia
Keywords: Ecological & conservation genetics
Genotype-environment associations (GEA) allow for the identification of variants and genomic regions that may provide possible adaptations to climate change. With the advent of large landscape genomics data sets the use of GEA is becoming increasingly common. However, studies in natural populations are usually not able to observe if the variants increase in frequency as populations undergo strong selection due to climate change. Here we track the impact of the recent California mega-drought on associated SNPs in Mimulus cardinalis, a riparian, montane plant found across California and Southern Oregon. We carried out 8-21X whole genome sequencing on 55 populations sampled range-wide before the 2012-2015 drought. Using BayPass we identified over 20,000 SNPs associated with climate, and track their change yearly from 2010 to 2016. SNPs conferring possible adaptation to greater heat, lower precipitation and increased moisture deficit increased in frequency through the drought when compared to randomly selected neutral SNPs. We will illustrate the importance of these regions through genetic offset analyses that outline what regions of M. cardinalis are particularly genetically vulnerable to future climate change conditions.