Speciation towards tetraploidization after intermediate processes of non-sexual reproduction
Speciation towards tetraploidization after intermediate processes of non-sexual reproduction
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DOI：
10.1098/rstb.2008.0048
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发表时间：
2008-09-12
影响因子：
6.3
通讯作者：
Coelho, Maria M.
中科院分区：
文献类型：
--
作者：
Cunha, Carina;Doadrio, Ignacio;Coelho, Maria M.
多倍体、杂交和交配系统的变异是深入了解动物进化的核心问题。伊比利亚物种Alburnoides是一个结合所有三种现象的例子。以往的研究表明，S.白纹伊蚊种群主要由三倍体和二倍体杂交形式（主要是雌性）组成，四倍体形式很少或不存在。杜罗河流域的两个种群揭示了一个不同的情景：四倍体个体占种群的85.6 - 97.5%，没有观察到性别比例偏差。基于血液和精子细胞的流式细胞术测量，微卫星位点和实验杂交，我们在这里首次描述了两个对称的异源四倍体群体（CCAA），在经历非有性生殖的中间过程后恢复正常减数分裂，产生一个新的有性生殖多倍体物种。前合子机制（生境选择和选择性交配）和后合子机制（不能存活的胚胎）是造成与其他类型的S. alburnoides复合体（e. G. CA、CAA）。这个例子说明了杂交多倍体复合体是如何导致物种形成的。
Polyploidy, hybridization and variation in mating systems are central issues for a deeper understanding of animal evolution. The Iberian species Squalius alburnoides represents an example combining all three phenomena. Previous studies showed that S. alburnoides populations are mainly composed of triploid and diploid hybrid forms ( mainly females), and that the tetraploid forms are rare or absent. Both populations from the Douro drainage reveal a distinct scenario: tetraploid individuals represent 85.6 - 97.5% of the population, with no sex ratio bias observed. Based on the flow cytometry measurements of blood and spermatozoa cells, microsatellite loci and experimental crosses, we describe here, for the first time, two symmetric allotetraploid populations ( CCAA) that resumed normal meiosis after undergoing intermediate processes of non- sexual reproduction to give rise to a new sexually reproducing polyploid species. Prezygotic ( habitat selection and assortative mating) and postzygotic mechanisms ( nonviable embryos) are responsible for the reproductive isolation from other forms of the S. alburnoides complex ( e. g. CA, CAA). This example illustrates how hybrid polyploid complexes may lead to speciation.