The use of DNA microsatellite loci for Caretta caretta identification

Abstract

Caretta carettas, one of the members of Chelonidae family, live primarily in water, except the periods of their ovulation where they come out to the shores to lay their eggs. Following an incubation period of 50-60 days, the newborns return to sea water to continue their 10-12-year life. Studies using marking methodology of the animals have shown that females return to the same place for ovulation every 2-3 years. The development of molecular genetic studies gives us now opportunity to trace all these routes that Caretta carettas follow during their life cycle. One of the basic techniques that is used for identification in general is the polymorphic DNA microsatellite loci. These 2-4 base pair DNA segments are considered to be ideal for Caretta caretta identification also. In this study we tried to establish a protocol in order to identify both male and female carettas in tissue samples collected from animals in the Mediterranean shoreline in the southern Turkey once this shoreline is one of the main spots of them for ovulation. The sampling has been done from 89 locations (Dalyan, Dalaman, Fethiye, Patara, Kale, Kumluca, Belek, Kzlot, Demirtas, Gazipasa and Anamur) from 246 dead baby Caretta carettas. DNA was extracted using silica-based extraction technology from the tissue homogenates. Cc7 locus was selected for identification to be tested for its degree of polymorphic content and therefore power of discrimination in general. The methodology used is PCR, followed by polyacrilamide gel electrophoresis and silver staining.