Abstract：
Whether populations adapt to similar selection pressures using the same underlying genetic variants depends on population history and the distribution of standing genetic variation at the metapopulation level. Studies of sticklebacks provide a case in point: when colonizing and adapting to freshwater habitats, three-spined sticklebacks (Gasterosteus aculeatus) with high gene flow tend to fix the same adaptive alleles in the same major loci, whereas nine-spined sticklebacks (Pungitius pungitius) with limited gene flow tend to utilize a more heterogeneous set of loci. In accordance with this, we report results of quantitative trait locus (QTL) analyses using a backcross design showing that lateral plate number variation in the western European nine-spined sticklebacks mapped to 3 moderate-effect QTL, contrary to the major-effect QTL in three-spined sticklebacks and different from the 4 QTL previously identified in the eastern European nine-spined sticklebacks. Furthermore, several QTL were identified associated with variation in lateral plate size, and 3 moderate-effect QTL with body size. Together, these findings indicate more heterogenous and polygenic genetic underpinnings of skeletal armour variation in nine-spined than three-spined sticklebacks, indicating limited genetic parallelism underlying armour trait evolution in the family Gasterostidae.
摘要：
种群是否使用相同的潜在遗传变异适应相似的选择压力取决于种群历史和种群水平上的常备遗传变异的分布。对棘鱼的研究提供了一个恰当的例子:当殖民和适应淡水栖息地时，具有高基因流的三棘刺（Gasterosteusaculeatus）倾向于将相同的适应性等位基因固定在相同的主要基因座中，而基因流有限的九头棘刺（Pugitiuspungitius）倾向于利用一组更为异质的基因座。据此,我们报告了使用回交设计的数量性状基因座（QTL）分析的结果，表明西欧九头棘刺的侧板数量变化映射到三个中度效应QTL，与三头棘刺中的主要效应QTL相反，并且与先前在东欧九头棘刺中确定的四个QTL不同。此外，确定了几个与侧板大小变化相关的QTL，和三个具有体型大小的中效QTL。一起,这些发现表明，九头棘刺的骨骼装甲变异的异质性和多基因遗传基础比三头棘刺的多，表明Gasterostidae家族中装甲性状进化的遗传平行性有限。
