Molecular analysis of East Pacific green turtles that nest in Mexico

Chelonia mydas is one of the most studied species of marine reptiles and is according to IUCN and CITES is currently listed as Threatened. It has a global distribution in subtropical and tropical areas; the eastern Pacific population is also known under the subspecies Chelonia mydas agassizii. In Mexico, turtles nest from the coast of MichoacántotheRevillagigedoIslands,while in the Atlantic they nest in the Gulf of Mexico and the Caribbean.This work aims to determine if there is variation in the COI gene that differentiates populations in the East Pacific from those in the Atlantic in Mexico. Results: Among 60 analyzed sequences, 35 were downloaded from BOLD, and 25 samples came from two Mexican locations: The Gulf of Mexico and Pacific Ocean. COI sequencing yielded a 625 bp long fragment for 60 individuals of C. mydas. A total of 10 bp (1.6%) were polymorphic, and these defined 10 haplotypes. The phylogenetic tree construction was performed using maximum likelihood (ML) under the K2P nucleotide substitution model, with 10 000 bootstrap replicates. Clustering analysis and haplotype networks strongly suggest two distinct, major lineages, one from the Atlantic and one from the Pacific Ocean. Significance: This work provides information about variation in COI for green turtles that nest in Mexico and is relevant to conservation of this species. It also provides additional reference barcodes for marine turtles, in particular from Mexico.