Range-edge genetic diversity: locally poor extant southern patches maintain a regionally diverse hotspot in the seagrass Zostera marina
Range-edge genetic diversity: locally poor extant southern patches maintain a regionally diverse hotspot in the seagrass Zostera marina
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DOI：
10.1111/j.1365-294x.2012.05500.x
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发表时间：
2012-04-01
影响因子：
4.9
通讯作者：
Serrao, Ester A.
中科院分区：
文献类型：
--
作者：
Diekmann, Onno E.;Serrao, Ester A.
在后缘的避难人口预测包含更高的遗传多样性比那些从扩张，如在冰后期的tenonizations。然而，外围人口也预测有减少的多样性相比，中心的物种分布。我们的目标是测试这些预测，通过比较种群的遗传多样性分布的限制海草大叶藻码头，与种群中的物种先前描述的中央多样性热点。大叶藻种群显示下降的等位基因丰富度，杂合性和基因型丰富度的后缘和前缘相比，在北海/波罗的海地区的多样性热点。然而，当种群合并时，南部范围的遗传多样性与北海/波罗的海地区一样高，而前沿的遗传多样性仍然较低。在这些南部伊比利亚人口的遗传多样性下降相比，更中心的人口可能是漂移的影响，因为小的有效人口规模，作为一个结果，减少栖息地，低有性生殖和低基因流。然而，当考虑到整个南部边缘的分布，而不是每个人口，多样性是一样高的中心热点在北海/波罗的海地区。我们的结论是，每个人口的多样性模式评估可以掩盖真实的区域丰富度，是典型的后缘人口，发挥了关键作用，在物种地理历史和边缘多样性热点具有很高的保护价值。
Refugial populations at the rear edge are predicted to contain higher genetic diversity than those resulting from expansion, such as in post-glacial recolonizations. However, peripheral populations are also predicted to have decreased diversity compared to the centre of a species distribution. We aim to test these predictions by comparing genetic diversity in populations at the limits of distribution of the seagrass Zostera marina, with populations in the species previously described central diversity hotspot. Zostera marina populations show decreased allelic richness, heterozygosity and genotypic richness in both the rear edge and the leading edge compared to the diversity hotspot in the North Sea/Baltic region. However, when populations are pooled, genetic diversity at the southern range is as high as in the North Sea/Baltic region while the leading edge remains low in genetic diversity. The decreased genetic diversity in these southern Iberian populations compared to more central populations is possibly the effect of drift because of small effective population size, as a result of reduced habitat, low sexual reproduction and low gene flow. However, when considering the whole southern edge of distribution rather than per population, diversity is as high as in the central hotspot in the North Sea/Baltic region. We conclude that diversity patterns assessed per population can mask the real regional richness that is typical of rear edge populations, which have played a key role in the species biogeographical history and as marginal diversity hotspots have very high conservation value.