由宾夕法尼亚大学的韦伯·米勒领导的国际性研究小组对从两个塔斯马尼亚虎（袋狼）毛发中提取的DNA进行研究分析后发现，这种已灭绝了70年的澳大利亚动物，其灭绝原因可能是近亲繁殖。该研究发表在周一出版的《基因组研究》杂志上。
研究小组从两只塔斯马尼亚虎头部毛发中提取出DNA并进行了排序，一只为雄性，1902年被带到美国国家动物园，另一只为雄性，1893年死于伦敦动物园。
他们排列出了其细胞核和线粒体的DNA序列，结果发现，两个样本非常接近，样本之间的基因变异很少。一般来讲，遗传分化很少的物种会处于灭绝的风险中，典型的例子是非洲猎豹。
研究人员表示，长毛猛犸象能够在北极永久冻土中冰冻保存良好，因此可找到其毛发并从中提取DNA，而对塔斯马尼亚虎的研究显示，其DNA能够在各种各样的环境下长期保存，因此更容易获得。
1936年，最后一只塔斯马尼亚虎死于动物园，科学家宣布其灭绝。从灭绝动物的毛发中提取DNA的方法也曾用于长毛猛犸象的DNA研究。研究人员希望借此方法研究其它灭绝的动物，希望能有一天将一些灭绝动物复活。（生物谷Bioon.com）
生物谷推荐原始出处：
Genome Research Published in Advance January 12, 2009, doi:10.1101/gr.082628.108
The mitochondrial genome sequence of the Tasmanian tiger (Thylacinus cynocephalus)
Webb Miller1,10, Daniela I. Drautz1, Jan E. Janecka2, Arthur M. Lesk1, Aakrosh Ratan1, Lynn P. Tomsho1, Mike Packard1, Yeting Zhang1, Lindsay R. McClellan1, Ji Qi1, Fangqing Zhao1, M. Thomas P. Gilbert3, Love Dalén4, Juan Luis Arsuaga5, Per G.P. Ericson6, Daniel H. Huson7, Kristofer M. Helgen8, William J. Murphy2, Anders G?therstr?m9 and Stephan C. Schuster1,10
1Pennsylvania State University, Center for Comparative Genomics and Bioinformatics, University Park, Pennsylvania 16802, USA
2Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas 77843, USA
3Centre for Ancient Genetics, University of Copenhagen, DK-2100 Copenhagen, Denmark
4School of Biological Sciences, Royal Holloway, University of London, Egham TW20 0EX, United Kingdom
5Centro Mixto UCM-ISCIII de Evolución y Comportamiento Humanos, c/Sinesio Delgado 4 Pabellon 14, 28029 d, Spain
6Department of Vertebrate Zoology, Swedish Museum of Natural History, S-10405 Stockholm, Sweden
7Center for Bioinformatics Tübingen, Tübingen University, Tübingen, Germany
8Division of Mammals, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20013-7012, USA
9Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, S-752 36 Uppsala, Sweden
Abstract
We report the first two complete mitochondrial genome sequences of the thylacine (Thylacinus cynocephalus), or so-called Tasmanian tiger, extinct since 1936. The thylacine's phylogenetic position within australidelphian marsupials has long been debated, and here we provide strong support for the thylacine's basal position in Dasyuromorphia, aided by mitochondrial genome sequence that we generated from the extant numbat (Myrmecobius fasciatus). Surprisingly, both of our thylacine sequences differ by 11%–15% from putative thylacine mitochondrial genes in GenBank, with one of our samples originating from a direct offspring of the previously sequenced individual. Our data sample each mitochondrial nucleotide an average of 50 times, thereby providing the first high-fidelity reference sequence for thylacine population genetics. Our two sequences differ in only five nucleotides out of 15,452, hinting at a very low genetic diversity shortly before extinction. Despite the samples’ heavy contamination with bacterial and human DNA and their temperate storage history, we estimate that as much as one-third of the total DNA in each sample is from the thylacine. The microbial content of the two thylacine samples was subjected to metagenomic analysis, and showed striking differences between a wild-captured individual and a born-in-captivity one. This study therefore adds to the growing evidence that extensive sequencing of museum collections is both feasible and desirable, and can yield complete genomes.
