Genetic accommodation in the wild: evolution of gene expression plasticity during character displacement
Genetic accommodation in the wild: evolution of gene expression plasticity during character displacement
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DOI：
10.1111/jeb.13133
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发表时间：
2017-09-01
影响因子：
2.1
通讯作者：
Pfennig, D. W.
中科院分区：
文献类型：
--
作者：
Levis, N. A.;Serrato-Capuchina, A.;Pfennig, D. W.
生态特征置换被认为是促进多样化的关键，但对其基本机制知之甚少。我们研究了在铲足蟾蜍中基因表达可塑性的进化转变是否介导了性格的改变。其中，Spea bombifrons和S. multiplicata分别出现在异地分布（祖先条件），每一个产生替代，饮食诱导，幼虫ecomorphs：杂食动物，吃碎屑，食肉动物，专门吃虾。相反，当这两个物种同域分布（衍生条件）时，减少碎屑竞争的选择导致了S。这表明，性状置换可能是通过一种极端形式的遗传适应（遗传同化）而产生的，在这种适应中，可塑性丧失了。在这里，我们问我们是否可以推断出这一过程中的特定基因的调控变化的签名。特别是，我们研究了在一种变体中通常表达更高的基因（偏向基因）是否在S.同域分布的熊蜂与S.来自异地的bombifrons我们饲养的个体来自同域与异域的碎屑或虾，并测量了9个偏见基因的反应规范。虽然不同的基因表现出不同的基因调控进化模式，结合基因表达谱显示，同域个体确实失去了饮食诱导的基因表达可塑性存在于异地个体。因此，我们的数据提供了一个少数的例子，从自然种群中的遗传适应/同化可以追溯到特定基因的调控变化。这种遗传调节可能介导许多系统中的性格置换。
Ecological character displacement is considered crucial in promoting diversification, yet relatively little is known of its underlying mechanisms. We examined whether evolutionary shifts in gene expression plasticity (genetic accommodation') mediate character displacement in spadefoot toads. Where Spea bombifrons and S. multiplicata occur separately in allopatry (the ancestral condition), each produces alternative, diet-induced, larval ecomorphs: omnivores, which eat detritus, and carnivores, which specialize on shrimp. By contrast, where these two species occur together in sympatry (the derived condition), selection to minimize competition for detritus has caused S. bombifrons to become nearly fixed for producing only carnivores, suggesting that character displacement might have arisen through an extreme form of genetic accommodation (genetic assimilation') in which plasticity is lost. Here, we asked whether we could infer a signature of this process in regulatory changes of specific genes. In particular, we investigated whether genes that are normally expressed more highly in one morph (biased' genes) have evolved reduced plasticity in expression levels among S. bombifrons from sympatry compared to S. bombifrons from allopatry. We reared individuals from sympatry vs. allopatry on detritus or shrimp and measured the reaction norms of nine biased genes. Although different genes displayed different patterns of gene regulatory evolution, the combined gene expression profiles revealed that sympatric individuals had indeed lost the diet-induced gene expression plasticity present in allopatric individuals. Our data therefore provide one of the few examples from natural populations in which genetic accommodation/assimilation can be traced to regulatory changes of specific genes. Such genetic accommodation might mediate character displacement in many systems.