Davison A, Constant N, Tanna H, Murray J, Clarke B
Institute of Genetics, School of Biology, Queen's Medical Centre, University of Nottingham, University Park, Nottingham, UK.
Heredity (Edinb). 2009 Sep;103(3):268-78. doi: 10.1038/hdy.2009.49. Epub 2009 Apr 29.
Early research on the direction of coiling (chirality) in snails had a prominent role in the history of biology, and continues to mold current thinking about developmental evolution. Here, we investigated the pleiotropic effects of chirality alleles on shell shape and length, using a large set of data from the Polynesian land snail Partula suturalis. By examining the shells of individuals with different combinations of their own and their mother's chiral genotypes, we find that the effects of chiral genes on length and shape involve both the maternal genotype and the genotype of the individual itself. Thus, differences in shape are symptoms of developmental shifts caused by the chirality alleles, or by alleles at other loci in close linkage disequilibrium with them. Although changes in shell shape are not necessary concomitants of chiral evolution, the results illustrate the wider pleiotropic effects of the genes, or haplotypes, that influence chirality. As the data are a rare record of the association in nature between the phenotype and genotype of a locus showing maternal effects, the conclusions are likely to be relevant to the general understanding of the dynamics of maternal-effect genes, including how selection acts on them.
早期关于蜗牛盘绕方向（手性）的研究在生物学史上具有重要地位，并持续影响着当前关于发育进化的思考。在此，我们利用来自波利尼西亚陆生蜗牛Partula suturalis的大量数据，研究了手性等位基因对壳形状和长度的多效性影响。通过检查具有自身和其母亲不同手性基因型组合的个体的壳，我们发现手性基因对长度和形状的影响涉及母体基因型和个体自身的基因型。因此，形状差异是由手性等位基因或与其处于紧密连锁不平衡状态的其他位点的等位基因引起的发育变化的表现。尽管壳形状的变化不一定是手性进化的必然伴随现象，但结果说明了影响手性的基因或单倍型具有更广泛的多效性影响。由于这些数据是自然中一个显示母体效应的位点的表型与基因型之间关联的罕见记录，这些结论可能与对母体效应基因动态的一般理解相关，包括选择如何作用于它们。
