Barrowclough George F, Gutiérrez R J, Groth Jeffrey G
Department of Ornithology, American Museum of Natural History, Central Park West at 79th Street, New York, New York, 10024.
Department of Wildlife Management, School of Natural Resources, Humboldt State University, Arcata, California, 95521.
Evolution. 1999 Jun;53(3):919-931. doi: 10.1111/j.1558-5646.1999.tb05385.x.
Mitochondrial DNA control region sequences of spotted owls (Strix occidentalis) allowed us to investigate gene flow, genetic structure, and biogeographic relationships among these forest-dwelling birds of western North America Estimates of gene flow based on genetic partitioning and the phylogeography of haplotypes indicate substantial dispersal within three long-recognized subspecies. However, patterns of individual phyletic relationships indicate a historical absence of gene flow among the subspecies, which are essentially monophyletic. The pattern of haplotype coalescence enabled us to identify the approximate timing and direction of a recent episode of gene flow from the Sierra Nevada to the northern coastal ranges. The three subspecies comprise phylogenetic species, and the northern spotted owl (S. o. caurina) is sister to a clade of California (S. o. occidentalis) plus Mexican spotted owls (S o lucida); this represents a novel biogeographic pattern within birds. The California spotted owl had substantially lower nucleotide diversity than the other two subspecies; this result is inconsistent with present patterns of population density A causal explanation requires postulating a severe bottleneck or a selective sweep, either of which was confined to only one geographic region.
斑点猫头鹰（Strix occidentalis）的线粒体DNA控制区序列使我们能够研究这些北美西部森林鸟类之间的基因流动、遗传结构和生物地理关系。基于遗传分区和单倍型系统地理学的基因流动估计表明，在三个长期认可的亚种内存在大量扩散。然而，个体系统发育关系模式表明，这些亚种之间历史上不存在基因流动，它们基本上是单系的。单倍型合并模式使我们能够确定最近一次从内华达山脉到北部沿海山脉的基因流动事件的大致时间和方向。这三个亚种构成了系统发育物种，北方斑点猫头鹰（S. o. caurina）是加利福尼亚斑点猫头鹰（S. o. occidentalis）和墨西哥斑点猫头鹰（S o lucida）进化枝的姐妹种；这代表了鸟类中的一种新的生物地理模式。加利福尼亚斑点猫头鹰的核苷酸多样性明显低于其他两个亚种；这一结果与目前的种群密度模式不一致。一个因果解释需要假设一个严重的瓶颈或选择性清除，而这两者都只局限于一个地理区域。
