Genetic diversity and differentiation in a wide ranging anadromous fish, American shad (Alosa sapidissima), is correlated with latitude

Studies that span entire species ranges can provide insight into the relative roles of historical contingency and contemporary factors that influence population structure and can reveal patterns of genetic variation that might otherwise go undetected. American shad is a wide ranging anadromous clupeid fish that exhibits variation in demographic histories and reproductive strategies (both semelparity and iteroparity) and provides a unique perspective on the evolutionary processes that govern the genetic architecture of anadromous fishes. Using 13 microsatellite loci, we examined the magnitude and spatial distribution of genetic variation among 33 populations across the species' range to (i) determine whether signals of historical demography persist among contemporary populations and (ii) assess the effect of different reproductive strategies on population structure. Patterns of genetic diversity and differentiation among populations varied widely and reflect the differential influences o...覆盖物种种群全分布范围的研究，可揭示影响种群结构的历史偶然性与当代因素的相对作用，还能发掘出否则将被遗漏的遗传变异模式。美洲西鲱（American shad）是一种分布广泛的溯河洄游鲱形目鱼类，其种群历史动态与繁殖策略（兼具单次生殖与多次生殖两种模式）存在变异，为探究调控溯河洄游鱼类遗传架构的进化过程提供了独特视角。本研究利用13个微卫星位点（microsatellite loci），对该物种分布范围内的33个种群的遗传变异程度与空间分布格局展开分析，旨在（1）探明当代种群中是否仍留存有历史种群动态的信号；（2）评估不同繁殖策略对种群结构的影响。种群间的遗传多样性与遗传分化模式存在广泛差异，反映出差异化的影响因素……