Microsatellites
Overall, AMOVAs did not reveal significant population differentiation
(overall Fst values were between 0.000 and 0.035 and all associated Fst
p-values were > 0.05). Thus, the amount of genetic
variation attributable to differences between the assigned population
subsets was low and insignificant; most of the genetic differentiation
occurred within and among individuals (Table S3).
Alternatively, according to our STRUCTURE results, there are two
distinct genetic clusters (K = 2) in our dataset, providing evidence for
genetic differentiation across Florida with signatures of gene flow
between clusters. Specifically, the samples from St. George Island were
largely assigned to one cluster. Likewise, the samples from the
peninsula region were largely assigned to another single cluster with
minimal admixture. The samples from the ANF appear to have substantial
(nearly 50% overall) admixture of alleles associated with the peninsula
and St. George Island clusters (Figure 2).
Finally, based on results of the Mantel tests of the association between
genetic distance and geographic distance, we found weak to little
evidence of IBD across the different subsets (Figure 3). Thus, the
amount of genetic variation explained by geographic distance is low,
suggesting that the genetic differentiation of our samples is continuous
across geography rather than illustrating discrete populations separated
by specific barriers.