Ortego Joaquín, Aparicio José Miguel, Cordero Pedro J, Calabuig Gustau
Grupo de Investigación de la Biodiversidad Genética y Cultural, Instituto de Investigación en Recursos Cinegéticos, Ronda de Toledo s/n, Ciudad Real, Spain.
Proc Biol Sci. 2008 Sep 7;275(1646):2039-47. doi: 10.1098/rspb.2008.0475.
The genetic consequences of small population size and isolation are of central concern in both population and conservation biology. Organisms with a metapopulation structure generally show effective population sizes that are much smaller than the number of mature individuals and this can reduce genetic diversity especially in small sized and isolated subpopulations. Here, we examine the association between heterozygosity and the size and spatial isolation of natal colonies in a metapopulation of lesser kestrels (Falco naumanni). For this purpose, we used capture-mark-recapture data to determine the patterns of immigration into the studied colonies, and 11 highly polymorphic microsatellite markers that allowed us to estimate genetic diversity of locally born individuals. We found that individuals born in smaller and more isolated colonies were genetically less diverse. These colonies received a lower number of immigrants, supporting the idea that both reduced gene flow and small population size are responsible for the genetic pattern observed. Our results are particularly intriguing because the lesser kestrel is a vagile and migratory species with great movement capacity and dispersal potential. Overall, this study provides evidence of the association between individual heterozygosity and the size and spatial isolation of natal colonies in a highly mobile vertebrate showing relatively frequent dispersal and low genetic differentiation among local subpopulations.
小种群规模和隔离的遗传后果是种群生物学和保护生物学共同关注的核心问题。具有集合种群结构的生物通常表现出有效种群规模远小于成熟个体数量的情况，这可能会降低遗传多样性，尤其是在小型且隔离的亚种群中。在此，我们研究了杂合度与小隼（Falco naumanni）集合种群中出生地繁殖群大小和空间隔离之间的关联。为此，我们利用标记重捕数据来确定迁入所研究繁殖群的模式，并使用11个高度多态的微卫星标记来估计本地出生个体的遗传多样性。我们发现，在较小且更隔离的繁殖群中出生的个体遗传多样性较低。这些繁殖群接收的移民数量较少，这支持了基因流减少和种群规模小共同导致所观察到的遗传模式这一观点。我们的结果尤其引人关注，因为小隼是一种具有很强移动能力和扩散潜力的迁徙性易扩散物种。总体而言，本研究为一个高度移动的脊椎动物中个体杂合度与出生地繁殖群大小和空间隔离之间的关联提供了证据，该脊椎动物表现出相对频繁的扩散以及本地亚种群间较低的遗传分化。
