Intraspecific genetic variation of striped red mullet (Mullus surmuletus L.) in the Mediterranean Sea assessed by allozyme and random amplified polymorphic DNA (RAPD) analysis

Allozyme analysis on 20 putative enzyme-coding loci and RAPD analysis on 15 4 markers, amplified by eight decamer random primers, were used to assess t he genetic variation of striped red mullet, Mullus surmuletus L., collected from six locations in the Mediterranean Sea. Both methods were able to det ect a high degree of genetic polymorphism. For both methods, estimates of v ariance of allele frequencies (F-ST), and chi(2) analyses, revealed signifi cant differences (P < 0.05) among samples. Nei's genetic distance (D) among samples was low (mean D = 0.011 for allozymes; mean D = 0.018 for RAPDs) w ith data from both approaches revealing the sample from France to be most d istinct from the Greek samples. Nevertheless, although most of the genetic variation in allozymes was not correlated with geographical distance, a cor relation between genetic affinities and geographical area was found with RA PDs. It seems therefore that the RAPD method showed a more pronounced effec t of isolation-by-distance in comparison with allozymes, probably because o f the different number of markers of the red mullet genome examined with ea ch method. Overall, the RAPD technique can be introduced as a complementary tool in the population genetics of marine fishes, providing supplementary information in their genetic stock structure analysis.