Genetic composition and temporal genetic variation in Mytilus galloprovincialis populations of the Thermaikos gulf (Northern Aegean Sea)

Aliozymic variation and genetic differentiation were investigated in three (one natural and two cultured) populations of Mytilus galloprovincialis Lam arck (1819), from Thermaikos Gulf (Macedonia, Greece) using starch gel elec trophoresis. Low genetic distance values were found among the studied popul ations. The estimate of N(e)m (12.3) suggests some degree of isolation betw een the natural and the cultured populations. The estimated mean heterozygo sity values were lower than those found by other investigators for the same species elsewhere but similar to those previously reported from Greece. Co nsistent significant Ro heterozygote deficiency was observed at several loc i. Ho and lie mean values did not exhibit statistically significant changes between the two culture populations in the course of one year and three ye ar periods. In addition the temporal genetic variation of the two cultured populations was further examined in the course of the same periods. The obs erved significant heterogeneity of the genotype and allele frequencies of I dh-2, Pgm-1, Est-2 loci could be caused by the possible involvement of sele ction.