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首页> 外文期刊>BMC Ecology >Coexistence of diploid and triploid hybrid water frogs: population differences persist in the apparent absence of differential survival
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Coexistence of diploid and triploid hybrid water frogs: population differences persist in the apparent absence of differential survival

机译：二倍体和三倍体杂交水蛙并存：种群差异在明显缺乏差异性生存的情况下仍然存在

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Background The role of differential selection in determining the geographic distribution of genotypes in hybrid systems has long been discussed, but not settled. The present study aims to asses the importance of selection in structuring all-hybrid Pelophylax esculentus populations. These populations, in which the parental species (P. lessonae with genotype LL and P. ridibundus with genotype RR) are absent, have pond-specific proportions of diploid (LR) and triploid (LLR and LRR) genotypes. Results With data from 12 Swedish ponds, we first show that in spite of significant changes in genotype proportions over time, the most extreme ponds retained their differences over a six year study period. The uneven distribution of genotypes among ponds could be a consequence of differential selection varying among ponds (selection hypothesis), or, alternatively, of different gamete production patterns among ponds (gamete pattern hypothesis). The selection hypothesis was tested in adults by a six year mark-recapture study in all 12 ponds. As the relative survival and proportion of LLR, LR and LRR did not correlate within ponds, this study provided no evidence for the selection hypothesis in adults. Then, both hypotheses were tested simultaneously in juvenile stages (eggs, tadpoles, metamorphs and one year old froglets) in three of the ponds. A gradual approach to adult genotype proportions through successive stages would support the selection hypotheses, whereas the presence of adult genotype proportions already at the egg stage would support the gamete pattern hypothesis. The result was a weak preference for the gamete pattern hypothesis. Conclusions These results thus suggest that selection is of little importance for shaping genotype distributions of all-hybrid populations of P. esculentus, but further studies are needed for confirmation. Moreover, the study provided valuable data on genotype-specific body lengths, adult survival and sex ratios.
机译：背景技术差异选择在确定杂交系统中基因型地理分布中的作用已被讨论很长时间，但尚未解决。本研究旨在评估选择在构建全混种Pelophylax esculentus种群中的重要性。这些种群中不存在亲本物种（基因型为LL的小白僵菌和基因型为RR的ridibundus rididaundus），这些种群具有池塘特异性比例的二倍体（LR）和三倍体（LLR和LRR）基因型。结果根据来自12个瑞典池塘的数据，我们首先表明，尽管基因型比例随时间发生了显着变化，但最极端的池塘在长达6年的研究期内仍保留了它们的差异。池塘之间基因型分布的不均匀可能是池塘间差异选择（选择假设）或池塘间不同配子生产模式（配子模式假设）的差异所致。通过对所有12个池塘进行为期六年的标记回收研究，对成年选择假设进行了测试。由于池塘内LLR，LR和LRR的相对存活率和比例不相关，因此本研究没有为成年选择假设提供证据。然后，在三个池塘的幼年阶段（蛋，t，变态动物和一岁的小蛙）同时检验了这两个假设。通过连续阶段逐步评估成年基因型比例将支持选择假设，而已经处于卵期的成年基因型比例的存在将支持配子模式假说。结果是对配子模式假设的偏爱偏弱。结论因此，这些结果表明，选择对于塑造食肉全杂交种群的基因型分布意义不大，但需要进一步的研究来确认。此外，该研究提供了有关基因型特异性体长，成年存活率和性别比的有价值的数据。

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