Genomic insights into marine environment adaptation and conservation of the threatened olive ridley turtle ( Lepidochelys olivacea)

Sea turtles are marine flagship species and most of them are currently in a threatened state. Long-term surviving in the ocean has driven significant morphological and physiological changes for this group, which makes them an ideal model for studying adaptive evolution of marine environments. Herein, we present a chromosome-scale genome of Lepidochelys olivacea with a genome size of 2.22 Gb and a contig N50 of 97.3 Mb. Comparative genomic analyses uncovered a suite of adaptive changes in genes related to olfaction, vision, virus defense, and longevity, which may help explain the genetic underpinnings of its marine environment adaptation. We also observed that the genome-wide heterozygosity of L. olivacea was low (6.45e-4), consistent with its prolonged population decline. Overall, our study provides valuable genetic resources for understanding evolutionary adaptations to aquatic environment and for the conservation of this threatened species.