Population analysis of the sand smelt Atherina boyeri Risso, 1810 (Teleostei Atherinidae) from Italian coastal lagoons by Random Amplified Polymorphic DNA (RAPD-PCR)

Atherina boyeri Risso, 1810 is a euryhaline species of ecological and economic relevance, highly diffused in most Mediterranean coastal lagoons and characterized by high morphological variability among populations. To study the genetic relationships among A. boyeri populations, 11 Italian lagoons and 2 freshwater lakes were sampled and a random amplified polymorphic DNA analysis was performed. Six arbitrarily designed primers were used. Of the 43 scored markers, 39 were polymorphic. No population-specific markers were found. Statistical analysis based on inferred allele frequencies (using Wright's F(st) statistic) and on presence or absence of bands (using analysis of molecular variance) revealed significant population structure. Unweighted pair group method with arithmetic mean cluster analysis based on Nei's genetic distances showed a geographic clustering of populations. Mantel tests confirmed a high correlation between genetic and geographic distances along coasts. These results suggest the occurrence of coastal gene flows among populations, probably because the anadromic behavior of this species may be only partially phylopatric. However, these migratory movements have not blurred the existing differences among populations.