Landscape genomics studies focus on identifying candidate genes under selection via spatial variation in abiotic environmental variables, but rarely by biotic factors such as disease. The Tasmanian devil (Sarcophilus harrisii) is found only on the environmentally heterogeneous island of Tasmania and is threatened with extinction by a nearly 100% fatal, transmissible cancer, devil facial tumor disease (DFTD). Devils persist in regions of long-term infection despite epidemiological model predictions of species’ extinction, suggesting possible adaptation to DFTD. Here, we test the extent to which spatial variation and genetic diversity are associated with the abiotic environment and/or DFTD. We employ genetic-environment association analyses using a RAD-capture panel including 6,886 SNPs from 3,286 individuals sampled pre- and post-disease arrival. Pre-disease, we find significant correlations of allele frequencies with environmental variables, including 365 unique loci linked to 71 genes, suggesting local adaptation to abiotic environment. The majority of candidate loci detected pre-DFTD were not detected post disease arrival. Several post-DFTD candidate loci were associated with disease prevalence and were in linkage disequilibrium with genes involved in tumor suppression and immune response. Loss of apparent signal of abiotic local adaptation post-disease suggests swamping by the strong selection resulting from the rapid onset of DFTD.

CSV file containing sample information for devils sampled pre-DFTD arrival

Pre_Devils.csv

CSV file containing sample information for devils sampled post-DFTD arrival

Post_Devils.csv

Filtered VCF file containing individuals sampled pre-DFTD arrival

pre_vcf.vcf.gz

Filtered VCF file containing individuals sampled post-DFTD arrival

post_vcf.vcf.gz