Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Canada.
PLoS One. 2013 Jul 29;8(7):e70296. doi: 10.1371/journal.pone.0070296. Print 2013.
Taxonomically exhaustive and continent wide patterns of genetic divergence within and between species have rarely been described and the underlying evolutionary causes shaping biodiversity distribution remain contentious. Here, we show that geographic patterns of intraspecific and interspecific genetic divergence among nearly all of the North American freshwater fish species (>750 species) support a dual role involving both the late Pliocene-Pleistocene climatic fluctuations and metabolic rate in determining latitudinal gradients of genetic divergence and very likely influencing speciation rates. Results indicate that the recurrent glacial cycles caused global reduction in intraspecific diversity, interspecific genetic divergence, and species richness at higher latitudes. At the opposite, longer geographic isolation, higher metabolic rate increasing substitution rate and possibly the rapid accumulation of genetic incompatibilities, led to an increasing biodiversity towards lower latitudes. This indicates that both intrinsic and extrinsic factors similarly affect micro and macro evolutionary processes shaping global patterns of biodiversity distribution. These results also indicate that factors favouring allopatric speciation are the main drivers underlying the diversification of North American freshwater fishes.
种内和种间遗传分歧的分类学上详尽和大陆范围的模式很少被描述，塑造生物多样性分布的潜在进化原因仍然存在争议。在这里，我们表明，几乎所有北美的淡水鱼类物种（>750 种）的种内和种间遗传分歧的地理模式支持一个双重作用，涉及晚上新世-更新世气候波动和代谢率，以确定遗传分歧的纬度梯度，并很可能影响物种形成率。结果表明，反复的冰川周期导致全球范围内种内多样性、种间遗传分歧和高纬度地区物种丰富度的减少。相反，更长的地理隔离、更高的代谢率增加替代率，以及可能的遗传不兼容性的快速积累，导致了更低纬度地区生物多样性的增加。这表明内在和外在因素同样影响塑造全球生物多样性分布模式的微观和宏观进化过程。这些结果还表明，有利于异域物种形成的因素是北美淡水鱼类多样化的主要驱动因素。
