Tursiops truncatus genetic analysis by DNA markers

A recent law rules the captive breeding of Tursiops truncatus (T.t.) and prevents the introduction of new wild subjects in Italian delphinariums (D.M. n.469,6/12/2001). Microsatellite markers and D-loop mitochondrial polymorphism are widely used for identity/parentage control and analysis of the origin and genetic variability in several animal species. In the present work we characterized genetically the great part of the subjects of Tursiops truncatus ssp kept in captivity in Italy to get information to improve breeding programmes. Genomic and mitochondrial DNA from peripheral blood, blowhole mucosal swabs or necropsy tissues was extracted from 15 animals. Fourteen microsatellite loci informative in T.t. and 558bp of mitochondrial control region (Genbank#AF155161) were amplified by PCR and analyzed by fluorescent automatised methods. Mitochondrial sequences were aligned by Clustal W., genetic distance analysis calculated and a tree created by Phylip package using NEIGHBOR program and UPGMA option. Microsatellite markers allowed to genotype all the subjects and confirmed the parentage relationships. Mitochondrial control region analysis revealed 9 different haplotypes clustering in four different groups (Mediterranean Sea, Tenerife, Caribbean Sea and Mexican Gulf), according to the declared maternal origin of the capture areas. DNA polymorphism analysis clarified some genetic differences between the individuals of Tursiops truncates and suggests indication to orient mating plans and avoid the access of impreeding.