由牛津大學(xué)科學(xué)家組成的一個研究小組已經(jīng)證明，13000年前活動在不列顛群島以及歐洲和北美地區(qū)的大型貓科動物是獅子,，而不是美洲虎或者虎,。
該研究小組分析了從歐洲和美國采集的化石和殘余物的DNA,，確定了更新世（180萬年前-1萬年前）不列顛群島生存的貓科動物家譜。該研究發(fā)表在本周的《分子生態(tài)學(xué)》（Molecular Ecology）上,。
負(fù)責(zé)該項工作的牛津大學(xué)動物學(xué)系Ross Barnett博士表示,，這些古代的獅子體型較大，比現(xiàn)在美洲的獅子大25%,，有較長的腿更適合耐力跑,?；蜃C明更新世的獅子與現(xiàn)代獅子關(guān)系密切。同時,，石器時代留于山洞中的壁畫表明它們當(dāng)時已經(jīng)形成群居,，但雄性獅子還沒有長出鬃毛。
該小組還發(fā)現(xiàn),，生存于更新世的獅子可以分為兩支：一支定居在亞歐大陸北部以及阿拉斯加和加拿大育空地區(qū),，另一支來自北美洲南部。
這種異常分布與冰期有關(guān),。在冰期,，西伯利亞和阿拉斯加之間形成了陸橋，獅子可以通過陸橋從亞歐大陸來到北美,。后來,，北美的冰蓋阻隔了該遷移路線，從而產(chǎn)生了基因結(jié)構(gòu)上完全不同的兩種動物,。
這些生活在不列顛群島以及歐洲和北美地區(qū)的獅子的生存環(huán)境與目前非洲的大型貓科動物完全不同：在更新世,，英國是苔原凍土地帶，就像現(xiàn)在的俄羅斯草原一樣,，很多大型動物聚集那里,，如哺乳動物、羊毛犀牛,、巨型鹿等,。13000年前，這些獅子和大型食草動物在大滅絕中消失,。
該研究的合作者之一,，牛津大學(xué)野生動物研究保護(hù)協(xié)會的Nobby Yamaguchi博士還表示，目前仍然不清楚大滅絕的原因,，有研究表明可能與早期人類有關(guān),。同時，他認(rèn)為該研究有助于描繪大滅絕之前大型動物的食性,。對獅子的線粒體DNA分析表明,，在大滅絕前3萬-4萬年，它們已經(jīng)喪失了大量遺傳多樣性,?？赡茉蚴蔷植繙缃^和種群重建，或者因?yàn)槟承┆{子群有優(yōu)勢而取代了其它群,，但這一說法尚未被證實(shí),。（生物谷Bioon.com）
生物谷推薦原始出處：
Molecular Ecology Volume 18 Issue 8, Pages 1668 - 1677
Phylogeography of lions (Panthera leo ssp.) reveals three distinct taxa and a late Pleistocene reduction in genetic diversity
ROSS BARNETT*, BETH SHAPIRO?, IAN BARNES?, SIMON Y. W. HO§, JOACHIM BURGER?, NOBUYUKI YAMAGUCHI**, THOMAS F. G. HIGHAM??, H. TODD WHEELER??, WILFRIED ROSENDAHL§§, ANDREI V. SHER??,????, MARINA SOTNIKOVA***, TATIANA KUZNETSOVA???, GENNADY F. BARYSHNIKOV???, LARRY D. MARTIN§§§, C. RICHARD HARINGTON???, JAMES A. BURNS**** and ALAN COOPER????
*Department of Zoology, University of Oxford, Oxford OX1 3PS, UK, ?Department of Biology, Pennsylvania State University, University Park, PA 16801, USA, ?Department of Biology, University College London, London WC1E 6BT, UK, §Centre for Macroevolution and Macroecology, School of Botany and Zoology, Australian National University, Canberra, ACT 0200, Australia, ?Institute of Anthropology, Mainz University, 55099 Mainz, Germany, **Department of Biological and Environmental Sciences, University of Qatar, PO Box 2713, Doha, Qatar, ??Research Laboratory for Archaeology, University of Oxford, Oxford OX1 3QJ, UK, ??George C. Page Museum of La Brea Discoveries, Los Angeles, CA 90036, USA, §§Reiss-Engelhorn-Museen, D-68159 Mannheim, Germany, ??Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, 119071 Moscow, Russia, ***Geological Institute, Russian Academy of Sciences, 119017 Moscow, Russia, ???Palaeontological Department, Geological Faculty, Moscow State University, 119899 Moscow, Russia, ???Zoological Institute, Russian Academy of Sciences, 199034 St Petersburg, Russia, §§§Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66045, USA, ???Canadian Museum of Nature (Palaeobiology), Ottawa, ON, Canada K1P 6P4, ****Quaternary Palaeontology, Royal Alberta Museum, Edmonton, AB, Canada T5N 0M6, ????School of Earth and Environmental Sciences, University of Adelaide, Adelaide, SA 5005, Australia
Lions were the most widespread carnivores in the late Pleistocene, ranging from southern Africa to the southern USA, but little is known about the evolutionary relationships among these Pleistocene populations or the dynamics that led to their extinction. Using ancient DNA techniques, we obtained mitochondrial sequences from 52 individuals sampled across the present and former range of lions. Phylogenetic analysis revealed three distinct clusters: (i) modern lions, Panthera leo; (ii) extinct Pleistocene cave lions, which formed a homogeneous population extending from Europe across Beringia (Siberia, Alaska and western Canada); and (iii) extinct American lions, which formed a separate population south of the Pleistocene ice sheets. The American lion appears to have become genetically isolated around 340 000 years ago, despite the apparent lack of significant barriers to gene flow with Beringian populations through much of the late Pleistocene. We found potential evidence of a severe population bottleneck in the cave lion during the previous interstadial, sometime after 48 000 years, adding to evidence from bison, mammoths, horses and brown bears that megafaunal populations underwent major genetic alterations throughout the last interstadial, potentially presaging the processes involved in the subsequent end-Pleistocene mass extinctions.
