Biochemical genetic differentiation between Pomatoschistus marmoratus and P-tortonesei

Several diagnostic genetic markers were identified in Pomatoschistus marmor atus and P. tortonesei using polyacrylamide gel electrophoresis (PAGE) of a llozymes. Twenty-one loci were resolved, including the electrophoretic patt ern of muscle proteins. The MDH*, PGM-1,2*, EST-1,2*, FUM* and PGI-2* loci exhibited different alleles which were fixed for the two species being anal ysed. Genetic distance, as calculated by Nei's index, showed a value of 0.4 13. Environmental hypersalinity, could have influenced the geographical dis tribution of P. tortonesei. (C) 1999 The Fisheries Society of the British I sles.