據(jù)澳大利亞廣播公司(ABC)網(wǎng)站報(bào)道,，科學(xué)家發(fā)現(xiàn)一種魚，經(jīng)過三代進(jìn)化便可適應(yīng)溫度的迅速變化,。
這是已經(jīng)記錄的進(jìn)化速度最快的野生動(dòng)物,。研究報(bào)告將發(fā)表在《皇家學(xué)會(huì)學(xué)報(bào)B》雜志上。該研究第一研究員洛凡·巴雷特說：“這是第一份通過實(shí)驗(yàn)顯示某種野生動(dòng)物能快速適應(yīng)氣候變化的研究,。”但這位英屬哥倫比亞大學(xué)進(jìn)化遺傳學(xué)家警告,，這一進(jìn)化大躍進(jìn)會(huì)付出很大代價(jià)：死亡率較高。
在他們的研究中,，來自加拿大和歐洲的科學(xué)家把棘魚從海中撈出,，然后把它們放入溫度逐漸降低的水池中，并對(duì)這些魚進(jìn)行了為期3年的研究,。他們發(fā)現(xiàn),，經(jīng)過三代進(jìn)化(每年一代)，棘魚便可以在2.5攝氏度的水中生存,，這一溫度低于它們祖輩的生存極限,。
研究顯示，至少有些動(dòng)物可能會(huì)經(jīng)過快速改變?cè)诳赡艿臍夂蜃兓行掖嫦聛?。之前的大部分氣候研究預(yù)言,，未來幾十年內(nèi)全球氣溫將逐漸升高數(shù)度，伴隨出現(xiàn)的將是極端冷和極端熱的天氣,。巴雷特說：“但是并不能因?yàn)槲覀兛吹酱罅窟M(jìn)化反應(yīng)就意味著自然群體能適應(yīng)氣候變化而不受任何影響,。在這3年研究中，約95%的魚死掉了,，只有5%的魚在進(jìn)化中適應(yīng)了寒冷,。失去群體約 95%的結(jié)果可能是災(zāi)難性的，因?yàn)槭Ｓ嗟?%可能無法維持自然群體,。我們現(xiàn)在尚不清楚這一遺傳特征的基因基礎(chǔ),。”
巴雷特在不列顛哥倫比亞大學(xué)獲得博士學(xué)位后轉(zhuǎn)入哈佛大學(xué)，他表示,，還需要進(jìn)行深入研究才能確定這類快速進(jìn)化是否可能發(fā)生在其他物種身上,，尤其是在氣候變暖而不是變冷之后。他指出，這類研究還可能為人類應(yīng)對(duì)氣候變化的方式提供線索,。在研究中,，這種海魚的快速進(jìn)化也映照出英屬哥倫比亞淡水棘魚長(zhǎng)達(dá)萬年的進(jìn)化，在冰河時(shí)代末期,，這種海魚的后代受困于內(nèi)陸,，并逐漸學(xué)會(huì)了在極端冷的環(huán)境中生存。
巴雷特指出,，自從首次走出非洲后,，人類也已經(jīng)進(jìn)化了大約一萬代，這不禁引出一個(gè)問題,，即北方人需要經(jīng)歷多少代才能進(jìn)化成適應(yīng)非洲祖先曾經(jīng)歷過的溫暖氣候的基因,？巴雷特說：“你可能會(huì)開始比較進(jìn)化率。”但他警告,，按照實(shí)驗(yàn)中棘魚95%的死亡率,，這類快速進(jìn)化“可能使得自然群體極其脆弱……，快速進(jìn)化總會(huì)有影響,。”（生物谷Bioon.com）
生物谷推薦原文出處：
Proceedings of the Royal Society B: Biological Sciences doi: 10.1098/rspb.2010.0923
Rapid evolution of cold tolerance in stickleback
Rowan D. H. Barrett1,*?, Antoine Paccard2,?, Timothy M. Healy1, Sara Bergek3, Patricia M. Schulte1, Dolph Schluter1 and Sean M. Rogers4
1Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
2Laboratoire de Botanique évolutive, Institut de biologie, Emile Argand 11, 2009 Neuchatel, Switzerland
3Swedish Board of Fisheries, Institute of Coastal Research, Skolgatan 6, 742 42 ?regrund, Sweden
4Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada T2N 1N4
Climate change is predicted to lead to increased average temperatures and greater intensity and frequency of high and low temperature extremes, but the evolutionary consequences for biological communities are not well understood. Studies of adaptive evolution of temperature tolerance have typically involved correlative analyses of natural populations or artificial selection experiments in the laboratory. Field experiments are required to provide estimates of the timing and strength of natural selection, enhance understanding of the genetics of adaptation and yield insights into the mechanisms driving evolutionary change. Here, we report the experimental evolution of cold tolerance in natural populations of threespine stickleback fish (Gasterosteus aculeatus). We show that freshwater sticklebacks are able to tolerate lower minimum temperatures than marine sticklebacks and that this difference is heritable. We transplanted marine sticklebacks to freshwater ponds and measured the rate of evolution after three generations in this environment. Cold tolerance evolved at a rate of 0.63 haldanes to a value 2.5°C lower than that of the ancestral population, matching values found in wild freshwater populations. Our results suggest that cold tolerance is under strong selection and that marine sticklebacks carry sufficient genetic variation to adapt to changes in temperature over remarkably short time scales.
