Population Genetic Structure and Reduced Diversity in Upstream Populations of the Endangered Nakdong Nose Loach ( Koreocobitis naktongensis ) Revealed by Novel Microsatellite Markers
We developed and validated seven polymorphic microsatellite loci for the endangered Nakdong nose loach ( Koreocobitis naktongensis ) and used them to assess genetic diversity and population structure across the Nakdong River basin in the Republic of Korea. The loci showed reliable Mendelian segregation within five full‐sib families, and no evidence of null alleles was detected. Genotyping of 126 individuals from eight sites revealed substantial overall genetic diversity (mean A R = 4.46; H E = 0.759) although diversity was lower in several populations upstream of dams (WS: A R = 3.70, H E = 0.681; DCR: 4.17, 0.709; GHR: 3.66, 0.655). Genetic differentiation was greater in comparisons involving some upstream populations, and a significant isolation‐by‐distance pattern indicated that river distance contributed to genetic structuring across the basin. Across analyses, WS and DCR + GHR were populations upstream of dams that were most consistently differentiated from the others. These results provide evidence of spatial genetic structure within the basin and highlight WS and DCR + GHR as priorities for future monitoring and conservation planning.