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In brief : No sex please

点击量:   时间:2017-05-15 04:02:06

A NEW report may explain why asexual reproduction is found more often in cold climates than warm ones. As early as 1928, researchers noticed that closely related species in the northern hemisphere reproduce asexually in northern parts and sexually further south. Joel Peck and his colleagues at the University of Sussex in Brighton developed a mathematical model to test ideas about why this might be. Their results back the theory that warm climates, where populations flourish, send out migrants that are ill-adapted to life in the cold north. Northern species exclude these migrants by reproducing asexually. Species in northern climates, on the other hand, are less productive and send fewer migrants south, so southern species can reproduce sexually without fear of their gene pool being undermined by migrants’ maladapted genes (Nature, vol 391, p 889). “The process seems to account for most of what’s known about the geographic distribution of sexual and asexual populations,” says Peck,