Evidence for contemporary and historical gene flow between guppy populations in different watersheds, with a test for associations with adaptive traits
Evidence for contemporary and historical gene flow between guppy populations in different watersheds, with a test for associations with adaptive traits
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DOI：
10.1002/ece3.5033
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发表时间：
2019-04-01
影响因子：
2.6
通讯作者：
Bentzen, Paul
中科院分区：
文献类型：
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作者：
Blondel, Lea;Baillie, Lyndsey;Bentzen, Paul
在树枝状河流系统中，基因流预计主要发生在流域内。然而，也可能发生罕见的跨流域转移，无论是由（通常是历史）地质事件还是（通常是当代）人类活动介导的。我们探讨了这些事件及其潜在的进化后果，通过分析模式的中性遗传变异（微卫星）和适应性表型变异（雄性颜色）分布在两个流域的野生孔雀鱼（孔雀鱼）在北方特立尼达。我们发现了流域内基因流的预期签名，但我们也推断出至少有两个跨流域基因流的实例，一个在上游河段，一个进一步下游。上游的跨流域事件似乎是最近（41 +/-13年），这表明通过最近的洪水或无记录的人为运输扩散。下游的跨流域事件似乎要老得多（577 +/-265年），这表明了罕见的地质或气候事件的作用。除了这些强有力的签名，当代和历史的基因流，我们发现几乎没有证据的影响，大概适应性表型分化，除了在最近的一个例子，跨流域的基因流。在这个系统中的选择似乎压倒了基因流，至少在这里研究的时空尺度上是这样。
In dendritic river systems, gene flow is expected to occur primarily within watersheds. Yet, rare cross-watershed transfers can also occur, whether mediated by (often historical) geological events or (often contemporary) human activities. We explored these events and their potential evolutionary consequences by analyzing patterns of neutral genetic variation (microsatellites) and adaptive phenotypic variation (male color) in wild guppies (Poecilia reticulata) distributed across two watersheds in northern Trinidad. We found the expected signatures of within-watershed gene flow; yet we also inferred at least two instances of cross-watershed gene flowone in the upstream reaches and one further downstream. The upstream cross-watershed event appears to be very recent (41 +/- 13years), suggesting dispersal via recent flooding or undocumented human-mediated transport. The downstream cross-watershed event appears to be considerably older (577 +/- 265years), suggesting a role for rare geological or climatological events. Alongside these strong signatures of both contemporary and historical gene flow, we found little evidence of impacts on presumably adaptive phenotypic differentiation, except perhaps in the one instance of very recent cross-watershed gene flow. Selection in this system seems to overpower gene flowat least on the spatiotemporal scales investigated here.