美國(guó)研究人員日前在《基因組研究》雜志上報(bào)告說(shuō)，他們對(duì)虎鯨線粒體脫氧核糖核酸測(cè)序后發(fā)現(xiàn)了至少3個(gè)新的虎鯨物種,，這也表明全球海洋中存在不止一種虎鯨,。
在新研究中，研究人員通過(guò)“高度平行測(cè)序技術(shù)”對(duì)139只虎鯨線粒體的脫氧核糖核酸進(jìn)行了測(cè)序,。這批虎鯨來(lái)自北大西洋,、北太平洋以及南極大陸附近海域。研究人員最終發(fā)現(xiàn),，在南極海域生活的兩種分別主要以魚和海豹為食的虎鯨可能屬于新物種,，此外，北太平洋地區(qū)也存在新的虎鯨種群,。
領(lǐng)導(dǎo)這項(xiàng)研究的美國(guó)國(guó)家海洋和大氣管理局遺傳學(xué)家菲利普·莫林表示,，與其他鯨類一樣，虎鯨體內(nèi)的線粒體也很少隨著時(shí)間的推移發(fā)生變化,，因此不查看整個(gè)基因組很難發(fā)現(xiàn)新進(jìn)化的虎鯨物種,，但利用“高度平行測(cè)序技術(shù)”可以通過(guò)測(cè)量來(lái)自世界各地的虎鯨組織樣本完成對(duì)虎鯨線粒體的基因組測(cè)序，從而分辨出新物種,。(生物谷Bioon.com)
生物谷推薦原文出處：
Genome Research 10.1101/gr.102954.109
Complete mitochondrial genome phylogeographic analysis of killer whales (Orcinus orca) indicates multiple species
Phillip A Morin1,7, Frederick I Archer1, Andrew D Foote2, Julie Vilstrup2, Eric E Allen3, Paul Wade4, John Durban4, Kim Parsons4, Robert Pitman1, Lewyn Li5, Pascal Bouffard5, Sandra C Abel Nielsen2, Morten Rasmussen2, Eske Willerslev2, M. Thomas P Gilbert2 and Timothy Harkins6
1 National Marine Fisheries Service, Southwest Fisheries Science Center;
2 Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen;
3 Scripps Institution of Oceanography, Univ. of California San Diego;
4 National Marine Fisheries Service, Alaska Fisheries Science Center;
5 454 Life Sciences;
6 Roche Applied Science
Killer whales (Orcinus orca) currently comprise a single, cosmopolitan species with a diverse diet. However, studies over the last 30 years have revealed populations of sympatric "ecotypes" with discrete prey preferences, morphology and behaviors. Although these ecotypes avoid social interactions and are not known to interbreed, genetic studies to date have found extremely low levels of diversity in the mitochondrial control region, and few clear phylogeographic patterns worldwide. This low level of diversity is likely due to low mitochondrial mutation rates that are common to cetaceans. Using killer whales as a case study, we have developed a method to readily sequence, assemble, and analyze complete mitochondrial genomes from large numbers of samples to more accurately assess phylogeography and estimate divergence times. This represents an important tool for wildlife management, not only for killer whales but for many marine taxa. We used high-throughput sequencing to survey whole mitochondrial genome variation of 139 samples from the North Pacific, North Atlantic and southern oceans. Phylogenetic analysis indicated that each of the known ecotypes represents a strongly supported clade with divergence times ranging from approximately 150,000 to 700,000 years ago. We recommend that three named ecotypes be elevated to full species, and that the remaining types be recognized as subspecies pending additional data. Establishing appropriate taxonomic designations will greatly aid in understanding the ecological impacts and conservation needs of these important marine predators. We predict that phylogeographic mitogenomics will become an important tool for improved statistical phylogeography and more precise estimates of divergence times.
