Population genetic diversity of green turtles, Chelonia mydas, in the Mediterranean revisited

The Mediterranean green turtle regional management unit is one of the 17 management units of green turtles considered a global conservation priority. However, previous studies using different genetic markers revealed very little diversity and differentiation across populations due to the overdominance of one haplotype (CM-A13) in the Mediterranean. We, therefore, used a more informative marker, mitochondrial short tandem repeats (mtSTRs), in 431 samples collected along the eastern Mediterranean coasts of Turkey and Northern Cyprus. In addition, we added the mtSTR haplotypes of previous studies and reached a total of 980 samples covering 12 nesting beaches (almost 100% of the populations in the region). We identified 42 haplotypes, 4 of which were recorded for the first time in the region. The species has a genetic diversity in the region higher than previously thought, ranging from 0.54 (Sugozu, Turkey) to 0.934 (Israel) and with the most common haplotypes being 6-8-8-4 (26.5%), 6-8-5-4 (17.3%), and 6-8-6-4 (14.9%). The analysis of a more extensive data set of mtSTRs supported recognizing at least three management units in the Mediterranean. Furthermore, we used the new data to assess the origin of the turtles foraging in Israel. We determined that Samandag (Turkey) was the population of origin of most of the individuals. Overall, we show that mtSTRs highly improve the resolution to detect population structuring and source for this species and region.