Data from: Temporal population-genetic structure of eastern mosquitofish in a dynamic aquatic landscape

We analyzed the effect of periodic drying in the Florida Everglades on spatio-temporal population genetic structure of eastern mosquitofish (Gambusia holbrooki). Severe periodic drying events force individuals from disparate sources to mix in dry-season relatively deep-water refuges. In 1996 (a wet year) and 1999 (a dry year), we sampled mosquitofish at 20 dry-season refuges distributed in three water-management regions and characterized genetic variation for 10 allozyme and 3 microsatellite loci. In 1996, most of the ecosystem did not dry, while in 1999, many of our sampling locations were isolated by expanses of dried marsh surface. In 1996, most spatial genetic variation was attributed to heterogeneity within regions. In 1999, spatial genetic variation within regions was not significant. In both years, a small but significant amount of variation (less than 1% of the total variation) was partitioned among regions. Variance was consistently greater than zero among long-hydroperiod sites within a region, but not among short-hydroperiod sites within a region, where hydroperiod was measured as time since last marsh surface dry-down forcing fishes into local refuges. In 1996, all sites were in Hardy-Weinberg equilibrium. In 1999, we observed fewer heterozygotes than expected for most loci and sites suggesting a Wahlund effect arising from fish leaving areas that dried and mixing in deep-water refuges.

本研究分析了佛罗里达大沼泽地（Florida Everglades）的周期性干旱对东部食蚊鱼（*Gambusia holbrooki*）时空种群遗传结构的影响。强烈的周期性干旱事件会驱使来自不同栖息地的个体，在旱季相对较深的避难水域中聚集混合。本研究分别于1996年（湿润年）与1999年（干旱年），在分布于三个水资源管理区的20个旱季避难水域中采集食蚊鱼样本，并对10个同工酶（allozyme）位点与3个微卫星（microsatellite）位点的遗传变异进行了分型鉴定。1996年，该生态系统的大部分区域未发生干旱；而1999年，多数采样点被大片干涸的沼泽地表分隔开来。1996年，大部分空间遗传变异可归因于区域内的异质性。1999年，区域内的空间遗传变异不再显著。两年中，均有少量但显著的遗传变异（占总变异的1%以下）被分配至区域间。在区域内的长淹水周期样点中，遗传方差始终显著大于0，但在区域内的短淹水周期样点中则并非如此；其中淹水周期被定义为自上次沼泽地表干涸、迫使鱼类迁入当地避难水域以来的时长。1996年，所有样点均符合哈迪-温伯格平衡（Hardy-Weinberg equilibrium）。1999年，多数位点与样点的杂合子数量均低于预期值，这表明存在瓦隆德效应（Wahlund effect）——其源于干涸区域的鱼类迁出，并在深水避难水域中混合聚集。