Data from: Is dispersal guided by the environment? A comparison of interspecific gene flow estimates among differentiated regions of a newt hybrid zone.

How frequently genes pass through a hybrid zone may be influenced by the environment. Accordingly, in long hybrid zones that span more than one environmental setting, different patterns may emerge. We reconstruct the amount and direction of gene flow across such a heterogeneous hybrid zone in two species of marbled newts (Triturus marmoratus and T. pygmaeus), in four widely separated areas of the Iberian Peninsula from one mitochondrial and three nuclear genes. The main environmental conditions associated with the position of the contact zone are determined as precipitation, rivers, altitude and relief. Elsewhere its position is not correlated with any environmental factor and is instead determined by the shortest geographical distance between fixed positions at either side (mountains in the East and river in the West). In areas where the position of the zone is stable, gene flow was bidirectional. Where T. pygmaeus has superseded Triturus marmoratus over a large area gene flow was unidirectional. The prediction that a major river would reduce gene flow was not confirmed.

基因通过杂交带（hybrid zone）的频率可能受到环境的影响。因此，在跨越多种环境背景的长距离杂交带中，可能会出现各异的分布格局。本研究基于伊比利亚半岛四个相距甚远的区域的1个线粒体基因（mitochondrial gene）与3个核基因（nuclear gene）的数据，重建了两种大理石纹真螈（*Triturus marmoratus* 和 *T. pygmaeus*）穿过该异质性杂交带的基因流强度与方向。与接触带（contact zone）位置相关的主要环境因子包括降水、河流、海拔与地形起伏。在其余区域，接触带的位置与任何环境因子均无显著关联，而是由两侧固定分布位点（东侧为山地、西侧为河流）之间的最短地理距离所决定。在杂交带位置稳定的区域，基因流呈双向模式；而在矮真螈（*T. pygmaeus*）大范围取代大理石纹真螈的区域，基因流则为单向模式。此前提出的“大型河流会削弱基因流”的预测并未得到证实。