Inheritance pattern of EST-SSRs in self-fertilized larvae of the bay scallop Argopecten irradians

Null allele and marker segregation distortion are considered to be common in bivalve molluscs. To facilitate genetic analysis of the bay scallop, the inheritance patterns of nineteen EST-SSRs were tested in four self-fertilized families. While the filial genotypes in twelve segregations conformed to Mendelian inheritance, three locus-family cases showed the significant departure. Two loci confirmed Mendelian expectations when null alleles were considered. The molecular basis of null alleles was detected by redesigning primers in the external flanking regions, and single nucleotide mutations in primer annealing sites were responsible for the null allele. Based on our results, the inheritance pattern and null allele of novel microsatellite markers should be further tested before using them for population studies and parentage assignment in the bay scallop. Additionally, six markers were recommended as members of a standard marker panel for use in population genetic and parentage studies.