The bottlenose dolphin – adaptation to climate change

Bottlenose dolphin Tursiops gephyreus brazil brazil climate change

Climatic changes have led to extensive restructuring of the world's oceans. Marine organisms have responded to new conditions with various biological systems, including genomic adaptations. The increasing accessibility of next-generation DNA sequencing methods to study non-modeled species has recently made it possible to study genomic changes that underlie environmental adaptations. This study used double-digestible restriction site-associated DNA (ddRAD) sequence data to investigate the genomic basis of ecotype formation in the currently recognized species and subspecies of bottlenose dolphins (genus Tursiops) in the southern hemisphere.

Tursiops truncatus gephyreus brazil brazil atlantic ocean climate change

A genomic divergence at the subspecies level was confirmed between the coastal Bottlenose dolphin (T. truncatus truncatus) and the coastal Lahille Bottlenose dolphin (T. t. gephyreus) in the southwestern Atlantic (SWAO). Likewise, at the subspecies level, a divergence between the coastal (eastern Australia) Indo-Pacific bottlenose dolphin (T. aduncus) and the proposed Burrunan's bottlenose dolphin (T. australis) from southern Australia is suspected. Bottlenose dolphins living near the coast generally had a lower genomic diversity than offshore lines, a pattern that was particularly evident in T. t. gephyreus , which had an exceptionally low diversity. Genomic regions associated with cardiovascular, musculoskeletal and energy production systems appear to have undergone repeated adaptive evolutions in coastal lineages in the southern hemisphere. We suspect that comparable selective pressures in the coastal environment have elicited similar adaptive responses in each lineage, thus supporting the parallel evolution of coastal bottlenose dolphins. As climate change changes marine ecosystems worldwide, it is crucial to gain an understanding of the adaptive capacity of local species and populations.
Our study provides insights into important adaptive pathways that may be important for the long-term survival of whales and other organisms in a changing marine environment.

Genomic Divergence and the Evolution of Ecotypes in Bottlenose Dolphins (Genus Tursiops)