Bérubé M, Aguilar A, Dendanto D, Larsen F, Notarbartolo di Sciara G, Sears R, Sigurjónsson J, Urban-R J, Palsbøll P J
Department of Population Biology, University of Copenhagen, Denmark.
Mol Ecol. 1998 May;7(5):585-99. doi: 10.1046/j.1365-294x.1998.00359.x.
Samples were collected from 407 fin whales, Balaenoptera physalus, at four North Atlantic and one Mediterranean Sea summer feeding area as well as the Sea of Cortez in the Pacific Ocean. For each sample, the sex, the sequence of the first 288 nucleotides of the mitochondrial (mt) control region and the genotype at six microsatellite loci were determined. A significant degree of divergence was detected at all nuclear and mt loci between North Atlantic/Mediterranean Sea and the Sea of Cortez. However, the divergence time estimated from the mt sequences was substantially lower than the time elapsed since the rise of the Panama Isthmus, suggesting occasional gene flow between the North Pacific and North Atlantic ocean after the separation of the two oceans. Within the North Atlantic and Mediterranean Sea, significant levels of heterogeneity were observed in the mtDNA between the Mediterranean Sea, the eastern (Spain) and the western (the Gulf of Maine and the Gulf of St Lawrence) North Atlantic. Samples collected off West Greenland and Iceland could not be unequivocally assigned to either of the two areas. The homogeneity tests performed using the nuclear data revealed significant levels of divergence only between the Mediterranean Sea and the Gulf of St Lawrence or West Greenland. In conclusion, our results suggest the existence of several recently diverged populations in the North Atlantic and Mediterranean Sea, possibly with some limited gene flow between adjacent populations, a population structure which is consistent with earlier population models proposed by Kellogg, Ingebrigtsen, and Sergeant.
在北大西洋的四个以及地中海的一个夏季觅食区，还有太平洋的科尔特斯海，从407头长须鲸（Balaenoptera physalus）身上采集了样本。对于每个样本，确定了其性别、线粒体（mt）控制区前288个核苷酸的序列以及六个微卫星位点的基因型。在北大西洋/地中海和科尔特斯海的所有核基因座和线粒体基因座上均检测到显著程度的差异。然而，从线粒体序列估计的分化时间远低于巴拿马地峡隆起以来所经历的时间，这表明在两大洋分离后，北太平洋和北大西洋之间偶尔存在基因流动。在北大西洋和地中海内部，在地中海、北大西洋东部（西班牙）和西部（缅因湾和圣劳伦斯湾）的线粒体DNA中观察到显著的异质性水平。在西格陵兰岛和冰岛附近采集的样本无法明确归为这两个区域中的任何一个。使用核数据进行的同质性测试仅显示地中海与圣劳伦斯湾或西格陵兰岛之间存在显著的差异水平。总之，我们的结果表明在北大西洋和地中海存在几个最近分化的种群，相邻种群之间可能存在一些有限的基因流动，这种种群结构与凯洛格、英布里格森和塞尔 Sergeant 等人早期提出的种群模型一致。
