# 编者信息 熊荣川 明湖实验室 xiongrongchuan@126.com http://blog.sciencenet.cn/u/Bearjazz Several hypotheses have been proposed to explain such high mtDNA variation ( Webb et al. 2011 ). First, sympatric intraspecific divergences in mtDNA may be an artifact caused by nuclear mitochondrial pseudogenes, or numts . This is genetic material that has been translocated from the mitochondrial to the nuclear genome. These copies are assumed to be nonfunctional (Bensasson et al. 2001), evolve fast, accumulate frame shifts and stop codons, and show double peaks when sequenced ( Bertheau et al. 2011; Triant and Hayes 2011 ). Second, as stated above, the divergent lineages may in fact reflect cryptic species, implying that the taxonomy is incorrect. Recent avian examples include thrushes (Turdus spp.) in western Amazonas (O'Neill et al. 2011), the winter wren (Troglodytes troglodytes) in North America (Toews and Irwin 2008), and seven nonpasserine migratory birds from the Philippines (Lohman et al. 2010). 解释线粒体 DNA 的这种种内高变异有几种假设（ Webb et al. 2011 ）。首先，线粒体 DNA 的同域内 mtDNA 差异可能是由核 - 线粒体假基因（ numts ）引起的假象。这种假基因是已经从线粒体转移到核基因组的遗传物质。这些假设不起作用的拷贝（ Bensasson et al. 2001 ），进化迅速，积累了开放阅读框的移位和终止密码子，并在测序时表现出双峰现象（ Bertheau et al. 2011; Triant and Hayes 2011 ）。第二，如上所述，不同的谱系实际上可能反映了隐存种的存在，这意味着之前分类是不正确的。最近的鸟类例子包括亚马逊西部的画眉（ Turdus spp. ）（ O'Neill et al. 2011 ），北美的冬季鹪鹩（ Toews and Irwin 2008 ），以及七只来自菲律宾的非游牧候鸟（ Lohman et al. 2010 ）。 Hogner S , Laskemoen T , Lifjeld J T , et al. Deep sympatric mitochondrial divergence without reproductive isolation in the common redstart, Phoenicurus phoenicurus . Ecology and Evolution, 2012, 2(12):2974-2988.
# 编者信息 熊荣川 明湖实验室 xiongrongchuan@126.com http://blog.sciencenet.cn/u/Bearjazz Many species exhibit high levels of intraspecific morphological and genetic variation. Variation in mitochondrial DNA (mtDNA) is particularly prevalent, due to its faster evolutionary rate compared with nuclear DNA ( Avise 2000 ). Usually, such variation is confined to allopatric populations and can be explained by long periods of isolation with differing selection pressures and/or divergence due to genetic drift (Coyne and Orr 2004; Price 2008). High intraspecific mtDNA variation between individuals living in sympatry is less common, and more difficult to explain. Upon closer inspection, such divergent sympatric lineages often show evidence of divergence in other parts of the genome as well as reproductive isolation between the lineages, implying that they are in fact cryptic species (Hebert et al. 2004a; Haine et al. 2006). 许多物种表现出高度种内的形态和遗传变异。线粒体 DNA （ mtDNA ）的变异尤其突出，因为它的进化速度比核 DNA 更快（ Avise 2000 ）。通常，这种变异仅限于异域分布群体，其原因可归纳为长时间的隔离和受到不同的选择压力和 / 或遗传漂变导致的分化（ Coyne and Orr 2004; Price 2008 ）。共同生活的个体之间的高 mtDNA 变异不太常见，更难以解释。经过仔细观察，这种不同的同域谱系往往在基因组的其他部分显示出的分化以及谱系之间的生殖隔离，这意味着它们实际上是隐秘的物种分化（ Hebert et al. 2004a; Haine et al. 2006 ）。 Hogner S , Laskemoen T , Lifjeld J T , et al. Deep sympatric mitochondrial divergence without reproductive isolation in the common redstart, Phoenicurus phoenicurus . Ecology and Evolution, 2012, 2(12):2974-2988.
标签: 隐存种
