Genetics, adaptation, and invasion in harsh environments
Genetics, adaptation, and invasion in harsh environments
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DOI：
10.1111/j.1752-4571.2009.00117.x
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发表时间：
2010-03-01
影响因子：
4.1
通讯作者：
Nuismer, Scott L.
中科院分区：
文献类型：
--
作者：
Gomulkiewicz, Richard;Holt, Robert D.;Nuismer, Scott L.
我们分析了数学模型，以研究适应性的遗传基础如何影响一个种群的持久性，这个种群突然遇到了一个恶劣的环境，如果没有进化，它就会灭绝。这一结果对新物种的引进和因环境突然变化而面临生存威胁的已建立种群具有重要意义。这些模型涵盖了一系列的遗传假设，包括有助于绝对适应度的相同基因座，具有非相同基因座的双位点定量遗传模型，以及具有影响数量性状的主要和次要基因的模型。我们发现，作为一种普遍的（尽管不是普遍的）模式，随着更多的基因座对适应度的贡献，持久性的前景会缩小，实际上是因为随着基因座的增加，每个基因座的选择越来越弱，这甚至会压倒增加基因座可能提供的适应度的任何初始增强。当基因座对适应度的贡献不均等时，影响较小的基因可以显著降低灭绝风险。事实上，主要基因和次要基因可以协同作用，以减少进化生长所需的时间。这种相互作用也会增加灭绝的脆弱性，这不仅取决于基因如何相互作用，还取决于引入或新入侵种群的初始遗传结构。
We analyze mathematical models to examine how the genetic basis of fitness affects the persistence of a population suddenly encountering a harsh environment where it would go extinct without evolution. The results are relevant for novel introductions and for an established population whose existence is threatened by a sudden change in the environment. The models span a range of genetic assumptions, including identical loci that contribute to absolute fitness, a two-locus quantitative genetic model with nonidentical loci, and a model with major and minor genes affecting a quantitative trait. We find as a general (though not universal) pattern that prospects for persistence narrow as more loci contribute to fitness, in effect because selection per locus is increasingly weakened with more loci, which can even overwhelm any initial enhancement of fitness that adding loci might provide. When loci contribute unequally to fitness, genes of small effect can significantly reduce extinction risk. Indeed, major and minor genes can interact synergistically to reduce the time needed to evolve growth. Such interactions can also increase vulnerability to extinction, depending not just on how genes interact but also on the initial genetic structure of the introduced, or newly invaded, population.