Isolation and characterization of microsatellite loci in the longsnout catfish (Leiocassis longirostris).

摘要

This study was conducted to develop microsatellite loci to elucidate the population structure of longsnout catfish (Leiocassis longirostris) and aid the fishery management of this species in China. Microsatellite loci were isolated using a modified enrichment protocol. Genomic DNA was extracted from muscle tissues of two unrelated individuals using a standard proteinase K/phenol extraction protocol. The microsatellite-enriched DNA fragments were amplified by polymerase chain reaction (PCR) and then ligated into pGEM-T Easy vectors (Promega) and transformed into JM109 competent cells. 63 positive clones were screened and sequenced. The primers were screened for polymorphism in 30 individuals from three locations in China. 16 of the 40 loci examined were found to be polymorphic, while the other 24 primer pairs amplified monomorphic loci or failed to amplify a consistent product. The number of alleles per locus ranged from 2 to 14. Observed and expected heterozygosities ranged from 0.071-1.000 and from 0.070-0.901, respectively. No significant linkage disequilibrium was detected among the loci. Six of the 16 loci showed significant departures from Hardy-Weinberg equilibrium (P=0.005). The microsatellite loci presented in this study will be useful for investigating the population structure, genetic diversity and phylogeography of the longsnout catfish and other related species.