Characterization of a new molecular marker for investigating skate population genetics: Analysis of three Mediterranean skate species (genus Raja) of commercial interest as a test case

Abstract

In this study we describe a new set of primers specifically designed for the amplification of the mitochondrial control region in skates of the Rajinae subfamily. The suitability of the amplified region as molecular marker was tested on three Mediterranean skates species of commercial interest (Raja clavata, Raja asterias and Raja miraletus). Fifty-six skate samples collected from 6 locations around the Italian peninsula were molecularly typed for 324-332bp of the mitochondrial DNA control region. The target sequence was polymorphic and, therefore, informative in all three species. Although the number of individuals screened for each species/location was small, our data suggest that populations of R. clavata and R. miraletus in central Mediterranean are single stocks. Conversely, there may be two genetically differentiated forms of R. asterias: one in the Adriatic Sea and the other in the Ligurian/Tyrrehenian Seas which represent separate geographic units or stocks. The highest level of genetic variability was recorded for R. clavata (H = 0.61) and the lowest for R. miraletus (H = 0.17), with R. asterias showing an intermediate level (H = 0.29), though no variation was found within the two (Adriatic and Ligurian/Tyrrehenian) sub-populations of the latter. These preliminary data show the potential of the described primers set to be employed in skate population genetics and phylogeny.