Molecular Phylogeny of Sarawak Green Sea Turtle (Chelonia mydas) inferred by the D-loop region and 16S rRNA gene.

Abstract

This study aimed to sequence the D-loop region and 16S rRNA gene of Chelonia mydas in order to determine the relationships between 15 individuals of green sea turtles nesting in two separate islands of Sarawak, namely the Satang Besar Island and the Talang-Talang Island. A total of 15 D-loop region sequences of 360 bp and nine 16S rRNA gene sequences of 550 bp were obtained in this study. Results based on these two genes showed that there are some genetic variations between samples collected from both islands. Pairwise distance analysis revealed between zero to 6% genetic divergence using information on D-loop region and zero to 1.8% genetic divergence using 16S rRNA gene between individuals. The phylogenetic trees constructed using D-loop information revealed the presence of two clades in which clade A comprises of mixtures of individuals from both islands whereas clade B only showed individuals from Talang-Talang Island. Analysis of the 16S rRNA gene data set, only one clade was observed. More samples is needed in the future to clarify whether natal homing, chance-encounter or social facilitation hypothesis is more suited to Sarawak green turtle rookeries.