Expanding hybrid zone between Solea aegyptiaca and Solea senegalensis: genetic evidence over two decades
Expanding hybrid zone between Solea aegyptiaca and Solea senegalensis: genetic evidence over two decades
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DOI：
10.1111/j.1365-294x.2011.05034.x
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发表时间：
2011-04-01
影响因子：
4.9
通讯作者：
Bonhomme, F.
中科院分区：
文献类型：
--
作者：
Ouanes, K.;Bahri-Sfar, L.;Bonhomme, F.
在过去的几年里，已经描述和研究了几个海洋混合带。评估扩展混合区的运动对于提高我们对进化过程的理解至关重要。我们重新研究了埃及鳎和塞内加尔鳎之间的杂交区，这是22年前在突尼斯北方首次描述的，当时S.塞内加尔人发现在突尼斯湾，而当地捕获的S。埃及伊蚊是纯遗传的。六个人口样本收获的内部和外部的两种鱼类共存的地区进行等位酶和外显子引物内含子长度多态性的基因型。这两种类型的标记是一致的，并揭示了基因渗入确实发生在两个方向。在比塞大泻湖内的渐渗水平较高（36.4%），而在泻湖外的渐渗水平较低，表明这是杂交发生的主要区域，而在S. aegyptiaca和向北的S.塞内加尔人主张存在一个单一模式的混合区。本研究中计算的较高的渐渗水平（与以前报道的16%相比）和新发现的渐渗S。比泽塔泻湖中的埃及藻（aegyptiaca）似乎表明，两个类群之间的遗传交换是不断发展的，尚未稳定。
Several marine hybrid zones have been described and studied during the last years. Assessing the movements of extending hybrid zones is central to improve our understanding of evolutionary processes. We have re-examined the hybrid zone between Solea aegyptiaca and Solea senegalensis that was first described 22 years ago in northern Tunisia when introgressed S. senegalensis individuals were found in the Gulf of Tunis, whereas locally caught S. aegyptiaca were genetically pure. Six population samples harvested both inside and outside the area where the two fish species coexist were genotyped for allozymes and exon-primed intron length polymorphism. Both types of markers were congruent and revealed that introgression takes place indeed in both directions. A high introgression level (36.4%) in the Bizerta lagoon and much less outside indicate that this is the main area where hybridization occurs while introgression clines towards the south in S. aegyptiaca and towards the north in S. senegalensis plead in favour of the existence of a unimodal hybrid zone. The higher introgression level calculated in the current study (when compared to 16% reported formerly) and the newly found introgressed S. aegyptiaca in Bizerta lagoon seem to indicate that the genetic exchanges occurring between the two taxa are evolving and not stabilized yet.