Does the definition of a novel environment affect the ability to detect cryptic genetic variation?
Does the definition of a novel environment affect the ability to detect cryptic genetic variation?
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DOI：
10.1111/jeb.14238
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发表时间：
2023-10-28
影响因子：
2.1
通讯作者：
Plaistow，Stewart J.
中科院分区：
文献类型：
--
作者：
Riley，Camille L.;Oostra，Vicencio;Plaistow，Stewart J.
人为变化使种群暴露在其进化史中罕见或完全缺失的环境中。这种新颖的环境被假设释放了隐藏的遗传变异，这是一种可以促进进化的隐藏变异。然而，对这一假设的支持褒贬不一。一个可能的原因是“新环境”的含义不够清晰，“新环境”是一个包罗万象的术语，包含了对隐藏变异的暴露或隐藏有潜在对比影响的条件。在这里，我们使用荟萃分析方法来研究原始环境与新环境中多变量性状的总遗传变异的变化。为了确定新环境的定义是否可以解释隐藏遗传变异释放的混合支持，我们比较了绝对的新环境，那些在种群进化过去中没有代表的环境，和极端的新环境，那些涉及频率或幅度变化的环境存在于种群祖先中。尽管有足够的统计能力，但我们在新环境中没有发现遗传变异增加的大范围模式，并且发现新环境的类型并不能解释效应量的任何显著变化。当效应量通过实验设计进行划分时，我们发现基于广义方差测量的研究中遗传变异增加，而基于狭义方差测量的研究中变异减少，这支持了之前的研究。因此，遗传变异的来源，而不是新环境的定义，是理解环境依赖性遗传变异的关键，强调非加性遗传变异是隐性遗传变异的重要组成部分，也是未来研究的途径。在这个图形摘要中，左边的流程图概述了用于对新环境进行分类的标准。在右边，呈现了两个森林图：一个比较极端和绝对新环境之间的效应量（总遗传方差的标准化平均差异，SDV），另一个比较广义和狭义研究设计之间的效应量。
Anthropogenic change exposes populations to environments that have been rare or entirely absent from their evolutionary past. Such novel environments are hypothesized to release cryptic genetic variation, a hidden store of variance that can fuel evolution. However, support for this hypothesis is mixed. One possible reason is a lack of clarity in what is meant by ‘novel environment’, an umbrella term encompassing conditions with potentially contrasting effects on the exposure or concealment of cryptic variation. Here, we use a meta‐analysis approach to investigate changes in the total genetic variance of multivariate traits in ancestral versus novel environments. To determine whether the definition of a novel environment could explain the mixed support for a release of cryptic genetic variation, we compared absolute novel environments, those not represented in a population's evolutionary past, to extreme novel environments, those involving frequency or magnitude changes to environments present in a population's ancestry. Despite sufficient statistical power, we detected no broad‐scale pattern of increased genetic variance in novel environments, and finding the type of novel environment did not explain any significant variation in effect sizes. When effect sizes were partitioned by experimental design, we found increased genetic variation in studies based on broad‐sense measures of variance, and decreased variation in narrow‐sense studies, in support of previous research. Therefore, the source of genetic variance, not the definition of a novel environment, was key to understanding environment‐dependant genetic variation, highlighting non‐additive genetic variance as an important component of cryptic genetic variation and avenue for future research.AbstractIn this graphical abstract, a flow chart on the left outlines the criteria used to classify novel environments. On the right, two forest plots are presented: one comparing effect sizes (standardized mean difference in total genetic variance, SDV) between extreme and absolute novel environments, and the other comparing effect sizes between broad‐sense and narrow‐sense study designs.