由賓夕法尼亞大學(xué)的韋伯·米勒領(lǐng)導(dǎo)的國(guó)際性研究小組對(duì)從兩個(gè)塔斯馬尼亞虎（袋狼）毛發(fā)中提取的DNA進(jìn)行研究分析后發(fā)現(xiàn)，這種已滅絕了70年的澳大利亞動(dòng)物,，其滅絕原因可能是近親繁殖,。該研究發(fā)表在周一出版的《基因組研究》雜志上。
研究小組從兩只塔斯馬尼亞虎頭部毛發(fā)中提取出DNA并進(jìn)行了排序,，一只為雄性,，1902年被帶到美國(guó)國(guó)家動(dòng)物園，另一只為雄性,，1893年死于倫敦動(dòng)物園,。
他們排列出了其細(xì)胞核和線粒體的DNA序列，結(jié)果發(fā)現(xiàn),，兩個(gè)樣本非常接近,，樣本之間的基因變異很少。一般來(lái)講,，遺傳分化很少的物種會(huì)處于滅絕的風(fēng)險(xiǎn)中,，典型的例子是非洲獵豹。
研究人員表示,，長(zhǎng)毛猛犸象能夠在北極永久凍土中冰凍保存良好,，因此可找到其毛發(fā)并從中提取DNA，而對(duì)塔斯馬尼亞虎的研究顯示,，其DNA能夠在各種各樣的環(huán)境下長(zhǎng)期保存,，因此更容易獲得,。
1936年，最后一只塔斯馬尼亞虎死于動(dòng)物園,，科學(xué)家宣布其滅絕,。從滅絕動(dòng)物的毛發(fā)中提取DNA的方法也曾用于長(zhǎng)毛猛犸象的DNA研究。研究人員希望借此方法研究其它滅絕的動(dòng)物,，希望能有一天將一些滅絕動(dòng)物復(fù)活,。（生物谷Bioon.com）
生物谷推薦原始出處：
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.
