成人大片

Scientists at the 成人大片 have challenged the common assumption that genetic diversity of a species is a key indicator of extinction risk.听

Published in the journal , the scientists demonstrate that there is no simple relationship between genetic diversity and species survival. But, Dr Jo茫o Teixeira and Dr Christian Huber from the 成人大片鈥檚 School of Biological Sciences conclude, the focus shouldn鈥檛 be on genetic diversity anyway, it should be on habitat protection. 听

鈥淣ature is being destroyed by humans at a rate never seen before,鈥� says computational biologist Dr Huber. 鈥淲e burn forests, over-fish our seas and destroy wild areas and it鈥檚 estimated that about one million species are threatened with extinction, some within decades. 听

鈥淎lthough researchers agree that this rapid decline of species numbers has to be stopped, how that鈥檚 best tackled is still open to debate. 听

鈥淐onservation geneticists consider genetic diversity as an important way to assess if a species is threatened by extinction. The view is that as long as individuals are genetically different from each other (having high genetic diversity), there will always be individuals with the right genetic makeup to survive under adverse conditions. On the other hand, if a species shows little genetic diversity, it鈥檚 believed that the species is fragile and likely to become extinct.鈥澨�

Dr Teixeira and Dr Huber have compiled a wide range of evidence from laboratory experiments, field studies, and evolutionary theory which suggests a need for re-evaluation on the measurement and interpretation of genetic diversity for conservation.听

鈥淚n this paper, we鈥檝e shown that this simple relationship between genetic diversity and survival is often wrong,鈥� says population geneticist Dr Teixeira. 鈥淢ost of the genetic diversity within a genome is 鈥榥eutral鈥�, meaning that it neither improves nor diminishes an individual鈥檚 ability to survive or produce offspring. On the other hand, the genetic diversity that does affect survival is found in very specific regions of the genome and is not at all correlated with genome-wide genetic diversity.听

鈥淩esearchers need to investigate for each species individually which genetic mutations allow the species to thrive and which mutations lead to diseases that can threaten the species. There is certainly no simple 鈥榦ne-size-fits-all鈥� measure of extinction risk.鈥澨�Population geneticist Dr Jo茫o Teixeira

The authors finally warn that, although genetics can play an important role in certain cases, fixating on genetic diversity shifts much-needed focus away from the much bigger problem: habitat destruction.听

鈥淪ince the year 2000, wildlife habitat about eight times the area of the UK has been lost,鈥� says Dr Huber. 鈥淲ithout habitat, there is no wildlife. And without wildlife and the ecosystem services that humans rely on, we are ultimately risking our own security and survival here on Earth.鈥澨�