Department of Wildlife and Fisheries Sciences, Texas A & M University, College Station, TX 77843, USA.
J Evol Biol. 2010 Jul;23(7):1475-89. doi: 10.1111/j.1420-9101.2010.02014.x. Epub 2010 May 26.
Hybridization can generate novel phenotypes, and in combination with divergent selection along environmental gradients, can play a driving role in phenotypic diversification. This study examined the influence of introgressive hybridization and environmental variation on the phenotypic diversity of two pupfish species (Cyprinodon atrorus and Cyprinodon bifasciatus) endemic to the Cuatro Ciénegas basin, Mexico. These species occupy opposite environmental extremes and are comprised of multiple, intraspecifically isolated populations. However, interspecific hybridization occurs to various degrees within connecting, intermediate environments. Using geometric morphometric analysis, extensive variation of body shape was observed between and within species, and phenotypic variation was strongly correlated with environmental conditions. Furthermore, some introgressed populations exhibited unique phenotypes not found in either of the parents, and overall morphospace occupation was significantly higher in introgressed populations when compared to the parentals. Overall, we find environmental variation and transgressive segregation both appear to have been important in shaping phenotypic variation in this system.
杂交可以产生新的表型，并且与沿环境梯度的分歧选择相结合，可能在表型多样化中发挥驱动作用。本研究考察了渐渗杂交和环境变化对墨西哥四泉盆地特有两种小鱼（黑鳍刺鱼和双斑刺鱼）表型多样性的影响。这些物种占据着相反的环境极端，由多个种内隔离的种群组成。然而，在连接的中间环境中，种间杂交发生在不同程度上。通过几何形态分析，观察到种间和种内的体型存在广泛的变异，表型变异与环境条件强烈相关。此外，一些渐渗种群表现出了在亲本中没有发现的独特表型，并且与亲本相比，渐渗种群的总体形态空间占据显著更高。总的来说，我们发现环境变化和杂种优势分离都似乎在塑造这个系统的表型变异方面非常重要。
