Genetic identification of sparid species by isozyme markers:: application to interspecific hybrids

The successful performance of Sparus aurata in Mediterranean aquaculture has prompted the domestication of other sparid species and the production of their interspecific hybrids. Allozyme markers have proved to be very powerful to study genetic variation at interspecific level and have been applied to differentiate the sparid species: Sparus aurata, Pagrus pagrus, Pagellus bogaraveo, Diplodus sargus, Diplodus puntazzo, Lithognatus mormyrus, Dentex dentex and Spondyliosoma cantharus. Seventeen enzymes, revealing 24 loci were suitable for comparison purposes. Among them, only the AK * locus does not allow differentiation of species, while the remaining revealed qualitative allelic differences in a variable number of species. The most resolutive loci were: ENDOP *, EST *, G3PDH *, and LDH-1 *, which discriminated 24 out of 28 species pairs in a dual species comparison matrix. A practical application of this study, was to demonstrate the hybrid nature of the offspring resulting from crossing female S. aurata and male P. pagrus. The ADH * locus, revealed from liver, proved to be very resolutive in terms of band separation. In addition the EST * showed to be very convenient, as it can be revealed from fin and mucus, avoiding sacrificing the animals. (C) 1999 Elsevier Science B.V. All rights reserved.