POPULATION-STRUCTURE OF MYA ARENARIA ALONG THE NEW-ENGLAND COASTLINE

Sequences of the internal transcribed spacer (ITS-1) ribosomal DNA reg ion were compared among 88 soft-shell clams (Mya arenaria) from 12 sit es (within three general areas) along the New England coast to determi ne whether populations were genetically heterogeneous. Two sequence va riants were observed, with type 1 having a 3-nucleotide insertion and one point mutation relative to type 2. Allele-specific polymerase chai n reaction (PCR), using primers specific to each sequence type, was pe rformed to determine the distribution of individuals who had both alle lic forms. DNA from soft-shell clams collected from three areas (Cobsc ook Bay, Maine; Gulf of Maine; and southern New England) were compared . chi(2) analyses of allele-specific PCR results revealed no significa nt heterogeneity among the three population distributions.