How did some marine fish manage to make their way from the ocean to the freshwater habitats that become available after the last ice age? How were they able to differentiate from their marine counterparts?
A recent study published in Science lead by a team from Japan in collaboration with multiple authors from Portugal, Spain, Switzerland and the USA, provides some insights on this fundamental question. The study led by Asano Ishikawa, and coordinated by Jun Kitano, is entitled “A key metabolic gene for recurrent freshwater colonisation and radiation in fishes”. In summary, this study accurately shows a thorough example of how a genetic innovation allowed marine fish to colonize freshwater environments. One of the most interesting remarks of this study is that the genetic innovation is associated with the efficiency of the essential omega-3 fatty acid DHA in freshwater environments.
This study links ecology, physiology, and genetics through a dietary adaptation.
Photo credits: David Alexander Marques