FIRST DATA ON GENETIC DIVERSITY OF THE SMALL PEARL OYSTER PINCTADA RADIATA (LEACH, 1814) IN MEDITERRANEAN POPULATIONS BY MEANS OF THE MITOCHONDRIAL COX1 MARKER

This study gives a first molecular insight into the genetic structure of Pinctada radiata by analysing a mitochondrial DNA marker in four South-Central Mediterranean populations of this lessepsian bivalve. Specimens were collected from four central Mediterranean locations. Six polymorphic sites were found, defining seven haplotypes. Haplotype and nucleotide diversity values were low to moderate. The low levels of within-population genetic diversity detected in the present study are consistent with a scenario of founder effect, as expected for an invasive species. The shallow genetic structuring among the sampled populations may result from two factors – long larval duration which promotes the homogenization of the genetic pool through an effective gene flow or the current populations may not have had enough time to differentiate.