Molecular evolution of toothed whale genes reveals adaptations to echolocating in different environments.

Background: Echolocation was a key development in toothed whale evolution, enabling their adaptation and diversification across various environments. Previous bioacoustic and morphological studies suggest that environmental pressures have influenced the evolution of echolocation in toothed whales. This hypothesis demands further investigation, especially regarding the molecular mechanisms involved in the adaptive radiation of toothed whales across multiple habitats.

Breathing Air and Living Underwater: Molecular Evolution of Genes Related to Antioxidant Response in Cetaceans and Pinnipeds.

Cetaceans and pinnipeds are lineages of mammals that have independently returned to the aquatic environment, acquiring varying degrees of dependence on it while sharing adaptations for underwater living. Here, we focused on one critical adaptation from both groups, their ability to withstand the ischemia and reperfusion experienced during apnea diving, which can lead to the production of reactive oxygen species (ROS) and subsequent oxidative damage. Previous studies have shown that cetaceans and pinnipeds possess efficient antioxidant enzymes that protect against ROS.

Molecular Footprints on Osmoregulation-Related Genes Associated with Freshwater Colonization by Cetaceans and Sirenians.

The genetic basis underlying adaptive physiological mechanisms has been extensively explored in mammals after colonizing the seas. However, independent lineages of aquatic mammals exhibit complex patterns of secondary colonization in freshwater environments. This change in habitat represents new osmotic challenges, and additional changes in key systems, such as the osmoregulatory system, are expected.

Why are whales big? Genes behind ocean giants.

Gigantism is prevalent in animals, but it has never reached more extreme levels than in aquatic mammals such as whales, dolphins, and porpoises. A new study by Silva et al. has uncovered five genes underlying this gigantism, a phenotype with important connections to aging and cancer suppression in long-lived animals.