School of Natural Sciences, University of California at Merced, Merced, CA 95343, USA.
Mol Ecol. 2012 Feb;21(4):987-1004. doi: 10.1111/j.1365-294X.2011.05417.x. Epub 2012 Jan 9.
Present-day phylogeographic patterns have been shaped by the dual histories of lineages and places, producing a diversity of relationships that may challenge discovery of general rules. For example, the predicted positive correlation between dispersal ability and gene flow has been supported inconsistently, suggesting unaccounted complexity in theory or the comparative framework. Here, I extend the sympatric sister-species approach, in which variance between lineages and places is minimized, to sister clades and test a fundamental assumption of comparative genetic studies of dispersal: that taxa which evolved at the same time and in the same place will, if they have similar life histories and ecologies, have essentially the same phylogeographic structure. Phylogenetic analyses of 197 Stigmatopora pipefishes using two nuclear (creatine kinase intron 6, α-tropomyosin) and two mitochondrial (16S, noncoding region) loci revealed largely synchronous parallel diversification of sister clades that are codistributed from Western Australia to New Zealand, supporting the null hypothesis. Only one comparison, however, yielded a sympatric sister-species pair (the two stem species), so I also explored the potential for extant species sharing a substantial proportion of their evolutionary histories in sympatry to substitute for sister taxon comparisons. In eastern Australia, where strong environmental structure is lacking, phylogeographic differences between species that have been codistributed for ~85% of their evolutionary histories were consistent with tendencies favoured by their modest life-history differences, that is the larger, rarer species had lower genetic diversity. In contrast, in New Zealand, two species codistributed for ~70% of their evolutionary histories were both structured similarly by a strong biogeographic filter despite differences in life history. Rigorously quantifying the influence of intrinsic and extrinsic factors on phylogeographic structure may advance most efficiently through meta-analyses of contemporaneously codistributed taxa, including but not limited to sympatric sister species.
当今的系统地理格局是谱系历史和地点历史共同作用的结果，产生了多种关系，这可能会对发现普遍规律构成挑战。例如，谱系扩散能力与基因流之间的正相关预测并未得到一致支持，这表明理论或比较框架中存在未被考虑的复杂性。在这里，我扩展了同域姐妹种方法，该方法将谱系和地点之间的方差最小化，用于姐妹分支，并检验了比较遗传扩散研究的一个基本假设：如果它们具有相似的生活史和生态，那么在同一时间和同一地点进化的分类单元将具有基本相同的系统地理结构。使用两个核（肌酸激酶内含子 6、α-原肌球蛋白）和两个线粒体（16S、非编码区）基因座对 197 个石斑鱼进行的系统发育分析表明，分布于从西澳大利亚到新西兰的姐妹分支发生了大规模的同步平行多样化，支持了零假设。然而，只有一个比较得出了同域姐妹种对（两个茎种），因此我还探索了在同域中共享其进化历史的大部分的现存物种替代姐妹分类单元比较的潜力。在澳大利亚东部，缺乏强烈的环境结构，在进化历史的 85%左右共分布的物种之间的系统地理差异与它们适度的生活史差异所倾向的趋势一致，即较大、较稀有的物种具有较低的遗传多样性。相比之下，在新西兰，两个进化历史的 70%左右共分布的物种尽管生活史不同，但都受到强烈的生物地理过滤器的类似结构影响。通过对同时共分布的分类单元进行荟萃分析（包括但不限于同域姐妹种），严格量化内在和外在因素对系统地理结构的影响可能会最有效地推进研究。
