Department of Animal Behavior, University of Bielefeld, Postfach 100131, 33615 Bielefeld, Germany.
Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK.
Genes (Basel). 2020 Mar 11;11(3):298. doi: 10.3390/genes11030298.
The soft-shell clam is one of the most ancient invaders of European coasts and is present in many coastal ecosystems, yet little is known about its genetic structure in Europe. We collected 266 samples spanning a latitudinal cline from the Mediterranean to the North Sea and genotyped them at 12 microsatellite loci. In parallel, geometric morphometric analysis of shell outlines was used to test for associations between shell shape, latitude and genotype, and for a selection of shells we measured the thickness and organic content of the granular prismatic (PR), the crossed-lamellar (CL) and the complex crossed-lamellar (CCL) layers. Strong population structure was detected, with Bayesian cluster analysis identifying four groups located in the Mediterranean, Celtic Sea, along the continental coast of the North Sea and in Scotland. Multivariate analysis of shell shape uncovered a significant effect of collection site but no associations with any other variables. Shell thickness did not vary significantly with either latitude or genotype, although PR thickness and calcification were positively associated with latitude, while CCL thickness showed a negative association. Our study provides new insights into the population structure of this species and sheds light on factors influencing shell shape, thickness and microstructure.
软壳蛤是入侵欧洲沿海地区最古老的物种之一，存在于许多沿海生态系统中，但人们对其在欧洲的遗传结构知之甚少。我们收集了 266 个样本，这些样本横跨从地中海到北海的纬度梯度，并在 12 个微卫星基因座上对其进行了基因分型。同时，我们还使用壳轮廓的几何形态测量分析来检验壳形、纬度和基因型之间的关联，并对选定的壳进行了测量，以测量颗粒棱柱（PR）、交叉层（CL）和复杂交叉层（CCL）层的厚度和有机含量。研究检测到了强烈的种群结构，贝叶斯聚类分析确定了四个群体，分别位于地中海、凯尔特海、北海大陆沿岸和苏格兰。壳形的多元分析揭示了采集地点的显著影响，但与其他任何变量均无关联。壳厚度与纬度或基因型均无显著差异，尽管 PR 厚度和钙化与纬度呈正相关，而 CCL 厚度则呈负相关。本研究为该物种的种群结构提供了新的见解，并揭示了影响壳形、厚度和微观结构的因素。
