(Feb. 28) – Passion for marine environment combined with genetic studies. This is the starting point of the analysis of the evolutionary history of Antarctic fish ant its antifreeze proteins. The study, published by PNAS, a prestigious journal of the National Academy of Sciences, and soon-to-be published by Nature News & Views, has been led by the professors Tomaso Patarnello, from the Department of Comparative Biomedicine and Food, and Lorenzo Zane, from the Department of Biology of the University of Padova, in collaboration with researchers at Yale University. The study suggests that the acquisition of antifreeze proteins, dated between 42 and 22 million years ago, no longer poses the main factor that determined the success of Antarctic notothenioidei. “The research shows how in millions of years this fish called notothenioidei have adapted to polar conditions. Today, however, because of global warming, notothenioidei are in danger – Patarnello explains – and an increase of only 2°C would have a devastating impact on this fish”. “The evolutionary history – Patarnello adds – is now threatened by climate change that made the Southern Ocean which surrounds Antarctica one of the fastest warming regions in the world. The same characteristics that have allowed these fish to survive and thrive during the cooling earth will now make it extremely vulnerable to future warming”. Patarnello speaks about the research with enthusiasm: “There are many young people who love this world but it is very difficult to offer them a future. In Italy – he adds – there are group of excellence but the research funds are low compared to other European countries. Studies like this can only be achieved thanks to European funding. However I believe that in a moment of crisis, like the one we are living, is essential to invest in research because it can become synonymous of wealth”. “In this field – he concludes – is essential to collaborate with international researchers and bodies: these researches are the result of an exchange of information and data. This study is only part of a wider and more ambitious project that has to do with Antarctica and its fish population, and it will continue despite the few resources available”. (Gil/Peg)
WHO ARE THE NOTOTHENIOIDEI
In the Antarctic live fish and invertebrates that can survive at temperatures well below zero. For example, more than half of the fish population is composed by the suborder of notothenioidei, whose blood -they do not contain hemoglobin – has a greater resistance to freezing. The origin and diversification into more than 100 species of notothenioidei provide a model of how evolution works. A period of rapid cooling, occurred about 40 million years ago, led to the mass extinction of fish adapted to temperate waters of the Southern Ocean. The acquisition of antifreeze proteins allowed them to survive in waters with temperatures below zero. Adapting to the ecological niches left vacant, new species of notothenioidei contribute to the rich marine biodiversity of the Antarctic waters. The notothenioidei constitute a large part of the Antarctic fish fauna and represent the main source of food for predators at the apex of the food chain, such as penguins, seals and whales.
