Microsatellite Analysis of Genetic Diversity Between Loach with Different Levels of Ploidy

We used microsatellite markers to investigate the genetic parameters of three different polyploidy populations of Misgurnus anguillicaudatus from Honghu City, Hubei Province. Polyacrylamide gel electrophoresis banding patterns of diploid (2n), triploid (3n) and tetraploid loaches (4n) were analyzed with PopGen software. A total of 68 alleles were obtained from seven microsatellite loci and the polymorphism information content (PIC) indices were all above 0.5. The average expected mean heterozygosity values (He) were 0.8420, 0.7186 and 0.8521; the average observed mean heterozygosity values (Ho) were 0.9674, 0.9785 and 0.8928; and the Hardy-Weinberg P values were 0.3078, 0.3151 and 0.3762, for diploid, triploid and tetraploid individuals, respectively. The results indicated that the three populations were highly polymorphic, with no deviations from Hardy-Weinberg equilibrium observed at all the seven microsatellite loci. This indicated a high level of genetic diversity within the populations. A cluster analysis diagram showed that the shortest genetic distance was between diploid and tetraploid loaches and they shared a close phylogenetic relationship. The triploid and tetraploid individuals had the most distant phylogenetic relationship.