Allopatric origins of sympatric brook charr populations: colonization history and admixture
Allopatric origins of sympatric brook charr populations: colonization history and admixture
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DOI：
10.1111/j.1365-294x.2005.02523.x
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发表时间：
2005-04-01
影响因子：
4.9
通讯作者：
Bernatchez, L
中科院分区：
文献类型：
--
作者：
Fraser, DJ;Bernatchez, L
自然选择被认为是在许多北温带淡水鱼中出现表型和遗传分化种群共生的驱动力。然而，如果这些种群有不同的祖先起源，历史也可能导致它们的分歧。我们之前发现了选择在冰后期米斯塔西尼湖(加拿大魁北克)迁徙溪炭(Salvelinus Fontinaris)分化出和流入繁殖种群演化中的作用的证据。在这里，我们通过对7个微卫星座位的混合使用和空间分析，表明这些群体没有共同的起源。与来自周围排水系统的样本相比，不同的种群聚为两个不同的种群组，尽管流入种群似乎比流出种群更多地混合在两个种群组之间。这些结果值得注意，因为流出和流入的种群在线粒体DNA(控制区的338-bp序列)上是单态的，并且只是中等分化的(平均F-ST=0.10)。两个祖先种群的定居也与整个湖泊形成过程中已知的外流方向变化一致。除了深入了解祖先种群的殖民性质(即时间和方向)如何影响共生关系的表型差异外，我们的结果还表明，祖先种群在殖民某些湖泊栖息地的能力可能有所不同。
Natural selection is presumed to be the driving force behind the occurrence of phenotypically and genetically divergent populations in sympatry within many north temperate freshwater fishes. If, however, these populations have different ancestral origins, history could also contribute to their divergence. We previously found evidence for the role of selection in the evolution of divergent outflow and inflow breeding populations of migratory brook charr (Salvelinus fontinalis) inhabiting postglacial Mistassini Lake (Quebec, Canada). Here, we show that these populations do not have a common origin, through the use of admixture and spatial analyses with seven microsatellite loci. Divergent populations clustered into two different population groups when compared to samples from surrounding drainages, although inflow populations appeared to be more admixed between the two population groups than the outflow population. These results are noteworthy since outflow and inflow populations were monomorphic at mitochondrial DNA (338-bp sequence of the control region) and are only moderately differentiated (mean F-ST = 0.10). Colonization by two ancestral populations was also consistent with known outflow direction changes throughout lake formation. In addition to providing insight into how phenotypic divergence in sympatry may have been affected by the nature (i.e. timing and direction) of colonization of ancestral populations, our results also suggest that ancestral populations may have differed in their ability to colonize certain lake habitats.