SNP dataset for cape race brook trout

Many studies have investigated the loss of adaptive potential in
endangered or exploited species experiencing recent population declines.
Less research has studied adaptive genomic variation in small populations
known to have persisted for long periods, despite the unique contribution
that such populations provide for determining mechanisms underlying
population persistence in evolutionary and conservation modeling. Small
populations of Brook trout (Salvelinus fontinalis) have persisted in Cape
Race, Newfoundland for >12,000 years. We used
genotyping-by-sequencing data to investigate the demographic history and
adaptive genomic variation of 26 populations with effective population
sizes (Ne) ranging from 11 to 442, and to explore mechanisms underlying
long-term persistence. We show that all populations experienced
demographic declines following postglacial colonization but have remained
in their current, small Ne state for thousands of years. We also reveal
greater homozygosity in adaptive alleles within the smallest populations
and found signatures of adaptive divergence in small populations relating
to several abiotic and biotic factors. Our study illustrates how the
demographic history of a species can influence the adaptive dynamics of
small populations persisting over long time periods.