Genetic diversity and species identity of the critically endangered Rote Island snake-necked turtle, Chelodina mccordi Rhodin, 1994

Abstract

The endemic Chelodina mccordi is considered extinct in the wild; however, ex-situ populations are thriving and sampled for our genetic diversity assessment. We used three sequences resulting from blood and tissue samples of five individual turtles amplified for 650-bp cytochrome oxidase I (COI) fragment of the mitochondrial DNA. We analysed a total of 30 barcoding DNA sequences for phylogenetic relationships and genetic distances among Chelodina spp. Nucleotide diversity of eight C. mccordi samples is 0.007 ± 0.001 with a haplotype diversity of 0.893 ± 0.086. All these samples form a monophyletic clade that is sister to a clade of Australian and New Guinean long-necked turtles. Genetic distances calculated using Kimura 2-paramater model among C. mccordi sequences range between 0.2% and 1.5%, while a few others are without distance. The shortest genetic distance is between individuals from Rote Island, whereas the longest distance was found between individuals, each of which was derived from parental stocks originating in Rote and Timor islands. A genetic distance of 1.1% - 1.5% is likely to denote distinction at subspecies level. Results of this study could help in reintroducing captive individuals into their natural habitats. Thus, captive breeding programme of this species may help its conservation.