Ecological diversification in an adaptive radiation of plants: the role of de novo mutation and introgression.
Ecological diversification in an adaptive radiation of plants: the role of de novo mutation and introgression.
复制标题
植物适应性辐射中的生态多样化：从头突变和基因渗入的作用。
DOI：
10.1101/2023.11.01.565185
复制
发表时间：
2024
期刊：
影响因子：
--
通讯作者：
Wessinger,CarolynA
中科院分区：
文献类型：
--
作者：
Stone,BenjaminW;Wessinger,CarolynA
适应性辐射的特点是快速的生态多样化和物种形成事件，导致生态分化物种之间的模糊物种边界。因此，适应性辐射是理解物种如何形成和维持的关键系统，包括从头突变与生态适应中预先存在的变异的作用以及杂交事件的全基因组后果。例如，适应性基因渗入，其中有益的等位基因通过杂交在谱系之间转移，可以促进适应性辐射的多样化，并促进对新环境的适应。在这项研究中，我们采用全基因组重测序数据，调查蜂鸟授粉花的进化起源，并在PenstemonsubgenusDasanthera，一个小而多样的适应性辐射植物的系统发育不一致和基因渗入的全基因组模式的特征。我们发现，在这种辐射范围内，适合蜂鸟的洋红色花朵显然是从祖先的蓝紫色蜜蜂授粉花朵进化而来的。花色的这些变化伴随着一种关键花青素途径酶的各种失活突变，这表明独立的从头功能丧失突变是这种性状平行进化的基础。尽管基因渗入和系统发育不一致的模式在整个基因组中是异质的，但基因密度的强烈影响表明，一般来说，自然选择反对基因渗入，并在基因丰富的基因组区域保持遗传分化。我们的研究结果强调了从头突变和基因渗入作为进化变化来源的重要性，并表明从头突变在驱动适应性辐射平行进化中的作用。
Adaptive radiations are characterized by rapid ecological diversification and speciation events, leading to fuzzy species boundaries between ecologically differentiated species. Adaptive radiations are therefore key systems for understanding how species are formed and maintained, including the role of de novo mutations versus preexisting variation in ecological adaptation and the genome-wide consequences of hybridization events. For example, adaptive introgression, where beneficial alleles are transferred between lineages through hybridization, may fuel diversification in adaptive radiations and facilitate adaptation to new environments. In this study, we employed whole-genome resequencing data to investigate the evolutionary origin of hummingbird-pollinated flowers and to characterize genome-wide patterns of phylogenetic discordance and introgression inPenstemonsubgenusDasanthera, a small and diverse adaptive radiation of plants. We found that magenta hummingbird-adapted flowers have apparently evolved twice from ancestral blue-violet bee-pollinated flowers within this radiation. These shifts in flower color are accompanied by a variety of inactivating mutations to a key anthocyanin pathway enzyme, suggesting that independent de novo loss-of-function mutations underlie the parallel evolution of this trait. Although patterns of introgression and phylogenetic discordance were heterogenous across the genome, a strong effect of gene density suggests that, in general, natural selection opposes introgression and maintains genetic differentiation in gene-rich genomic regions. Our results highlight the importance of both de novo mutation and introgression as sources of evolutionary change and indicate a role for de novo mutation in driving parallel evolution in adaptive radiations.