Genetic characterization of over hundred years old <em>Caretta caretta</em> specimens from Italian and Maltese museums

Abstract

Museum collections have proven to be a useful source of samples for the reconstruction of evolutionary history and phylogeography of many taxa. This study was aimed at assessing the success rate in a genetic analysis of historical material, in order to explore the feasibility and eventually begin the diachronic description of Caretta caretta stocks in Italian and Maltese coastal waters. The endangered status of the species and the difficulty to study it in the wild make its common occurrence in Italian museum collections a valuable resource. We used minimally invasive methods to collect biological material from specimens dating from the end of the 19^th century to 2003, belonging to four museums. As a control for amplification success and absence of cross-contamination, four dinucleotide microsatellite loci of different average length (Cc7, Cc141, Cm72 and Cm84) were typed. All individuals with two or more successfully amplified microsatellites (36%) displayed distinct genotypes, thus excluding contamination as a major flaw in the data. We then targeted 380 bp of the mtDNA control region, which allows comparisons with many living populations worldwide and represents the optimal marker for the philopatric behaviour of this species. All individuals but 2 were successfully sequenced. Haplotype CC-A2 was found in 68 individuals, whereas CC-A1 and CC-A3 were found only in one Tyrrhenian and one S-Adriatic specimens, respectively. This study demonstrates that genetic analysis of marine turtles from museum specimens is feasible. Data generated from cohorts of several generations ago are potentially useful for research and dissemination purposes.