PDF(Pubmed)
Abstract：
Phenotypic plasticity is produced and maintained by processes regulating the transcriptome. While differential gene expression is among the most important of these processes, relatively little is known about other sources of transcriptional variation. Previous work suggests that alternative splicing plays an extensive and functionally unique role in transcriptional plasticity, though plastically spliced genes may be more constrained than the remainder of expressed genes. In this study, we explore the relationship between expression and splicing plasticity, along with the genetic diversity in those genes, in an ecologically consequential polyphenism: facultative diapause. Using 96 samples spread over two tissues and 10 timepoints, we compare the extent of differential splicing and expression between diapausing and direct developing pupae of the butterfly Pieris napi. Splicing differs strongly between diapausing and direct developing trajectories but alters a smaller and functionally unique set of genes compared to differential expression. We further test the hypothesis that among these expressed loci, plastically spliced genes are likely to experience the strongest purifying selection to maintain seasonally plastic phenotypes. Genes with unique transcriptional changes through diapause consistently had the lowest nucleotide diversity, and this effect was consistently stronger among genes that were differentially spliced compared to those with just differential expression through diapause. Further, the strength of negative selection was higher in the population expressing diapause every generation. Our results suggest that maintenance of the molecular mechanisms involved in diapause progression, including post-transcriptional modifications, are highly conserved and likely to experience genetic constraints, especially in northern populations of P. napi.
摘要：
表型可塑性是通过调节转录组的过程产生和维持的。虽然差异基因表达是这些过程中最重要的，对转录变异的其他来源知之甚少。先前的工作表明，可变剪接在转录可塑性中起着广泛和功能上独特的作用，尽管塑性变形剪接的基因可能比其余表达的基因更受限制。在这项研究中,我们探索表达和剪接可塑性之间的关系，以及这些基因的遗传多样性，在生态上相应的多表型中：兼性滞育。使用分布在两个组织和10个时间点的96个样本，我们比较了蝴蝶Pierisnapi的diapausing和直接发育p之间的差异剪接程度和表达。剪接在滞育和直接发育轨迹之间存在很大差异，但与差异表达相比，剪接改变了较小且功能独特的一组基因。我们进一步检验了以下假设：在这些表达的基因座中，可塑性剪接的基因可能会经历最强的纯化选择，以维持季节性的可塑性表型。通过滞育具有独特转录变化的基因始终具有最低的核苷酸多样性，与仅通过滞育差异表达的基因相比，这种作用在差异剪接的基因中始终更强。Further,在每一代表达滞育的群体中，负选择的强度更高。我们的结果表明，维持滞育进展的分子机制，包括转录后修饰，高度保守，可能经历遗传限制，尤其是在北部的P.napi种群中。
