Sea turtles exhibit natal homing and nesting site fidelity, with maternally inherited mitochondrial DNA (mtDNA) analysis aiding in identifying genetic stocks. Traditionally, turtle population genetics relies on a 300-800 base pair (bp) mtDNA control region; however, whole mitochondrial genome sequencing has recently uncovered genetic variations beyond the control region.
Green turtles (Chelonia mydas) are considered globally "endangered". This project focuses on green turtle ecology and conservation and is conducted in partnership with remote ranger groups. We used short (384 bp), long (770 bp), and whole mtDNA genome sequencing to assess genetic diversity and stock contributions at three foraging grounds (Kakadu, Cobourg, Croker Island) and for comparison to a 2010 mixed stock analysis.
MSA results showed no significant differences in stock contributions between sites or between analyses using short and long haplotypes. However, the Cobourg foraging area exhibited seasonal variation, with different genetic stock contributions in the dry season (May-August) and build-up period (October-November). Whole mitochondrial sequencing revealed greater haplotype diversity, with individuals from the largest haplotype (CmP83.1) at 770 bp splitting into 25 novel haplotypes, potentially improving accuracy for stock assessment.
Refining genetic analyses enhances understanding of turtle migration and anthropogenic threats, informing conservation and indigenous management strategies.