Development of microsatellite markers and comprehensive assessment on genetic variation of the red swamp crayfish (Procambarus clarkii) in Hubei province, China.

The red swamp crayfish (Procambarus clarkii) has become one of China's most important freshwater aquaculture species. As the epicenter of crayfish cultivation, Hubei province provides the majority of germplasm resources for breeding applications. However, the genetic diversity and population structure of P. clarkii in this area remains largely incomplete, hindering the effective utilization of these germplasm resources. In this study, 20 polymorphic microsatellites were developed and used to investigate genetic diversity and differentiation in representative P. clarkii populations from five cultivated and five wild populations in Hubei province. A total of 169 alleles were discovered at these loci, and the average polymorphic information content was calculated as 0.584. Diversity index of expected heterozygosity (He) indicated a relatively medium genetic diversity across all populations (0.431 ~ 0.565), while wild populations exhibited higher genetic diversity (He = 0.542) compared to that in cultured populations (He = 0.478). The average value of pairwise population differentiation index (Fst) was 0.108, manifesting a moderate level of genetic differentiation among populations. Analysis of molecular variance between ten populations revealed that genetic variation mostly resided within individuals (79.4%), with slightly higher variation observed in cultured populations (84.79%) compared to that in wild populations (80.52%). Bayesian assignment, dendrogram, and principal component analysis grouped the genotypes into three clusters with wide variation among the accessions. These results reflected substantial genetic differentiation presented in P. clarkii populations. Our findings shed light on the diversity status of P. clarkii in Hubei province and will be great value for genetic improvement through selective breeding. [ABSTRACT FROM AUTHOR]