Genetic component of flammability variation in a Mediterranean shrub

Recurrent fires impose a strong selection pressure in many ecosystems worldwide. In such ecosystems, plant flammability is of paramount importance because it enhances population persistence, particularly in non-resprouting species. Indeed, there is evidence of phenotypic divergence of flammability under different fire regimes. Our general hypothesis is that flammability-enhancing traits are adaptive; here we test whether they have a genetic component. To test this hypothesis we used the post-fire obligate seeder Ulex parviflorus from sites historically exposed to different fire recurrence. We associated molecular variation in potentially adaptive loci detected with a genomic scan (using AFLP markers) to individual phenotypic variability in flammability across fire regimes. We found that at least 42% of the phenotypic variation in flammability was explained by the genetic divergence in a subset of AFLP loci. In spite of generalised gene flow, the genetic variability was structured by dif...频繁火干扰在全球众多生态系统中施加了强劲的选择压力。在此类生态系统中，植物可燃性至关重要，因其可提升种群存续能力，对于非萌芽物种而言尤为如此。确有证据表明，在不同火制度下，植物可燃性会出现表型分化。我们的核心假说为：提升可燃性的性状具有适应性；本研究旨在检验此类性状是否存在遗传基础。为验证该假说，我们选取了历史上经历不同火复发频率的生境中的火烧专性播种物种小花荆豆（Ulex parviflorus）作为研究材料。通过基因组扫描（采用扩增片段长度多态性（AFLP）标记）检测到的潜在适应性位点的分子变异，与不同火制度下个体可燃性的表型变异进行关联分析。研究结果显示，至少42%的植物可燃性表型变异，可由部分AFLP位点的遗传分化所解释。尽管存在普遍的基因交流，遗传变异的结构仍受原文未完成内容的调控。