Whole-body enantiomorphy and maternal inheritance of chiral reversal in the pond snail Lymnaea stagnalis
Whole-body enantiomorphy and maternal inheritance of chiral reversal in the pond snail Lymnaea stagnalis
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DOI：
10.1093/jhered/esn032
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发表时间：
2008-09-01
影响因子：
3.1
通讯作者：
Falkner, Gerhard
中科院分区：
文献类型：
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作者：
Asami, Takahiro;Gittenberger, Edmund;Falkner, Gerhard
左侧和右侧蜗牛反复进化的左右逆转的双边不对称以及卷曲方向。然而，在大多数蜗牛物种，人口是固定的任何对映异构体和实验室育种是困难的，即使手性变种被发现，因此，只有少数实验模型的手性变化物种内已可用于研究初级不对称性的演变。我们已经建立了实验室线的对映体的池塘蜗牛Stagnalis从野生种群。杂交试验表明，L.停滞期由单个核基因座处的母体基因型决定，其中右旋等位基因对左旋等位基因是显性的。实地调查显示，该基因的左旋等位基因至少持续了10年，即大约10代。在Hardy-Weinberg平衡假设下，左侧等位基因频率波动较大，最高可达0.156。频率的变化表明，选择对手性逆转是不够强大，以抵消在一个短暂的小池塘的遗传漂变。由于作为模型动物的优势，L. stagnalis可以是在不同生物学科中研究手性方面的独特系统。
Sinistral and dextral snails have repeatedly evolved by left right reversal of bilateral asymmetry as well as coiling direction. However, in most snail species, populations are fixed for either enantiomorph and laboratory breeding is difficult even if chiral variants are found. Thus, only few experimental models of chiral variation within species have been available to study the evolution of the primary asymmetry. We have established laboratory lines of enantiomorphs of the pond snail Lymnaea stagnalis starting from a wild population. Crossing experiments demonstrated that the primary asymmetry of L. stagnalis is determined by the maternal genotype at a single nuclear locus where the dextral allele is dominant to the sinistral allele. Field surveys revealed that the sinistral allele has persisted for at least 10 years, that is, about 10 generations. The frequency of the sinistral allele showed large fluctuations, reaching as frequent as 0.156 in estimate under the assumption of Hardy-Weinberg equilibrium. The frequency shifts suggest that selection against chiral reversal was not strong enough to counterbalance genetic drift in an ephemeral small pond. Because of the advantages as a model animal, enantiomorphs of L. stagnalis can be a unique system to study aspects of chirality in diverse biological disciplines.