Evaluating the genetic status of a Great Basin endemic minnow: the relict dace (Relictus solitarius)

Abstract

The relict dace (Relictus solitarius) is an endemic minnow restricted to isolated spring systems within Butte, Goshute, Ruby and Steptoe valleys in the eastern Nevada portion of the Great Basin. It is the only native fish in these basins, but speckled dace (Rhinichthys osculus) have been introduced into some localities in Ruby Valley and, based on morphology, the two species are believed to have hybridized in those areas. We used DNA sequence data from one mitochondrial gene (cytochrome b) and one nuclear intron (S7) to determine if putative relict dace populations in Ruby Valley share mtDNA haplotypes with speckled dace, or show signs of hybridization. Results of our analyses show that 11 of 16 Ruby Valley populations sampled contain only speckled dace, and one speckled dace population exhibited signs of limited introgressive hybridization. The remaining five Ruby Valley populations that were sampled contain relict dace that remain genetically distinct from speckled dace. The integrity of the Ruby Valley relict dace populations should be actively protected, particularly in the area surrounding Ruby Lake where speckled dace have been widely introduced.

Pluvial Drainage Patterns and Holocene Desiccation Influenced the Genetic Architecture of Relict Dace, Relictus solitarius (Teleostei: Cyprinidae)

“…We examined DNA from seventy-nine relict dace specimens from eight natural populations; two from each of the four valleys where relict dace naturally occur ( S1 Table ). The two Ruby Valley populations included in this study were chosen because they do not exhibit genetic admixture with speckled dace that have been introduced into some Ruby Valley springs [ 39 ]. Nevada Department of Wildlife (NDOW) officials and Otis Bay Ecological Consultant (OBEC) biologists collected samples under authorized permits and procedures.…”

“…We amplified ND2 using primers ASN and ILE [ 40 ]. Protocols for PCR amplifications are described in detail by Houston et al [ 39 ].…”

“…We used purified PCR products as templates for cycle-sequencing reactions, and carried out Sanger sequencing according to methods described by Houston et al [ 39 ], the only difference being the primers used (ASN and ILE). For the previously published cyt b sequences, we used aligned sequences from Houston et al [ 39 ].…”

“…We used purified PCR products as templates for cycle-sequencing reactions, and carried out Sanger sequencing according to methods described by Houston et al [ 39 ], the only difference being the primers used (ASN and ILE). For the previously published cyt b sequences, we used aligned sequences from Houston et al [ 39 ]. We aligned the newly generated ND2 sequences using the automatic assembly feature in Sequencher v.4.8 (Gene Codes Corporation), then visually inspected the aligned sequences and made corrections manually, using a speckled dace ( Rhinichthys osculus ) ND2 sequence (GenBank: EU158191) and amino acid sequence as references.…”

“…solitarius populations within these four valleys had not differentiated based on lack of morphological differences across the species’ range [ 7 , 36 ]. However, recent mtDNA evidence shows that some genetic differentiation has occurred [ 39 ], although the timing of diversification among R . solitarius populations has yet to be determined.…”