RADseq samples from Smallmouth Bass Micropterus dolomieu for SNP panel lineage identification.

The Smallmouth Bass (Micropterus dolomieu; SMB) is one of the most widely distributed black bass species, but the southwestern edge of the Smallmouth Bass range in Missouri, Arkansas, and Oklahoma contains some of the most divergent ecotypes of the species such as the Neosho sub-species in the Arkansas River drainage in the Ozark Mountains and populations inhabiting the Ouachita Mountains. We therefore sought to develop a single nucleotide polymorphism (SNP) panel to be informative with respect to population-level studies of SMB within the range of the Neosho and Ouachita SMB lineages, including differentiating hybrids with sympatric Spotted Bass (M. punctulatus) and non-native northern SMB that have historically been stocked in the region. We obtained samples from 76 individuals from a variety of locations across the range of SMB, but concentrated within the Interior Highlands (N = 50). We included 3 Shoal Bass (M. cataractae) individuals as an outgroup and 3 Spotted Bass because they readily hybridize with Smallmouth Bass in their sympatric range. From these samples, we were able to construct a 192 SNP panel informative for identification of introgressive hybridization between SMB and Spotted Bass, between Northern SMB lineages and the two Interior Highlands SMB lineages, and identify major sources of genetic differentiation among systems within the native range of Neosho SMB and Ouachita lineages. Beyond being a tool for use in future conservation planning and assessments, major findings of this study include corroboration of at least three major lineages of SMB (Northern, Neosho, and Ouachita), major delineations between northern and southern populations of Northern SMB, and a separation of the Ouachita lineage according to two major watersheds (Little River and Ouachita River).