Department of Biology and Wildlife, Institute of Arctic Biology, University of Alaska Museum, 907 Yukon Drive, Fairbanks, AK 99775, USA.
Mol Ecol. 2011 Feb;20(3):573-83. doi: 10.1111/j.1365-294X.2010.04965.x. Epub 2010 Dec 24.
Proposals for genetic thresholds for species delimitation assume that simple genetic data sets (e.g. mitochondrial sequence data) are correlated with speciation; i.e. such data sets accurately reflect organismal lineage divergence. We used taxonomically stratified phenotypic levels of differentiation (populations, subspecies and species) among nine avian lineages using paired, trans-Beringian samples from three lineages each in three orders (Anseriformes, Charadriiformes, and Passeriformes) to test this assumption. Using mitochondrial DNA sequence data and nuclear genomic data (amplified fragment length polymorphisms), we found a lack of concordance between these two genomes in their respective estimates of divergence and little or no relationship between phenotype (taxonomic relatedness) and genetic differentiation between taxon pairs. There are several possible reasons for the discord observed (e.g. selection on one of the genomes or perhaps lineage sorting), but the implications are that genetic estimates of lineage divergence may not be correlated with estimates from other parts of the genome, are not well correlated with the speciation process and are thus not reliable indicators of species limits.
物种界定的遗传阈值的提议假设简单的遗传数据集（例如线粒体序列数据）与物种形成相关；也就是说，这些数据集准确地反映了生物体谱系的分化。我们使用三个目（雁形目、鸻形目和雀形目）中的三个谱系的每一个的跨白令海峡的配对样本，使用九个鸟类谱系的分类分层的表型分化水平（种群、亚种和物种）来检验这一假设。使用线粒体 DNA 序列数据和核基因组数据（扩增片段长度多态性），我们发现这两个基因组在它们各自的分歧估计中缺乏一致性，并且在分类单元对之间的表型（分类学上的亲缘关系）和遗传分化之间几乎没有关系或没有关系。观察到的不和谐有几个可能的原因（例如，一个基因组的选择，或者谱系排序），但这意味着谱系分化的遗传估计可能与基因组其他部分的估计不相关，与物种形成过程不相关，因此不是物种界限的可靠指标。
