Resolving the paradox of stasis: addressing the missing fraction problem

解决停滞悖论：解决缺失分数问题

• 批准号: NE/R011109/1
• 负责人: Michael Morrissey
• 金额: $ 83.27万
• 依托单位: University of St Andrews
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FR011109%2F1
• 关键词: Resolving; paradox; stasis; addressing; missing

Quantitative genetics has been exceptionally successful at predicting evolution in simple scenarios, for example, the response to artificial selection on a specific traits, such as milk yield in cattle, or body size in mice. Evolutionary quantitative genetics seeks to apply the same principles in nature. This endeavor has so far had much more mixed success. It is clear that the basic ingredients for adaptive evolutionary change, i.e., genetic variation for and natural selection of a trait, both occur frequently in natural populations. However, the rapid contemporary evolutionary change that would be expected from an abundance of heritability and selection is rarely observed. This set of observations has been called the "paradox of stasis". A paradox is only an *apparently* illogical scenario: theoretical evolutionary quantitative genetics has been extremely successful at generating potential solutions to the paradox. In general, applying these more advanced theories is challenging, and there is consequently a great paucity of data on the solutions to the paradox, relative to the quantity of data on simple quantities such as heritability and selection. We propose to tackle one of the most theoretically important solutions, which is also one of the least studied empirically.The "missing fraction problem" occurs if viability selection alters the distribution of a trait before it is expressed. For example, if individuals that would otherwise produce large values of a trait are likely to die before producing the trait (because of viability selection at an earlier stage of the life cycle on a correlated trait) then this selection will not be picked up in a selection analysis that relates available phenotypes to fitness: importantly, selection estimated in this naïve analysis will be upwardly biased. There are a number of opportunities to get around this problem, for example, by jointly modeling the selection and genetics of focal traits, along with early life viability (i.e., treat survival as a trait), or traits that may influence early survival. We organize these opportunities into a hierarchy of four levels. All of these levels make greater demands on data than typical studies of the selection and genetics of traits in the wild. However, different levels of analysis could potentially be achieved in many study systems.In our study system, the Soay sheep population on St Kilda, we are able to apply all four levels of the hierarchy to a range of traits, with a special focus on body size and reproductive scheduling. We will conduct a coordinated series of studies on the extent of the missing fraction problem that will generate a comprehensive analysis of how much accounting for this key issue can change evolutionary inferences in the wild. Additionally, we also propose (1) theoretical work to address the potential severity of the missing fraction problem across different life histories, (2) methodological developments to help researchers (including initially ourselves!) apply some of the most advanced available statistical methods to the problem, and (3) a synthetic review, summarizing the available theory, methods and key results (which by the end of this project will come in large part from our own study). Our study will thus provide a comprehensive step forward for evolutionary quantitative genetics, and will enable the field in general to begin to properly tackle one of its biggest outstanding problems.

定量遗传学在预测简单情况下的进化方面非常成功，例如，对特定性状的人工选择的反应，如牛的产奶量，或老鼠的体型。进化数量遗传学试图在自然界中应用同样的原理。到目前为止，这一努力取得了好坏参半的成功。很明显，适应性进化变化的基本要素，即性状的遗传变异和自然选择，都经常发生在自然种群中。然而，从丰富的遗传性和选择中预期的当代快速进化变化很少被观察到。这组观察结果被称为“停滞悖论”。悖论只是一个“显然”不合逻辑的场景：理论上的进化定量遗传学已经非常成功地为悖论提供了潜在的解决方案。一般来说，应用这些更先进的理论是具有挑战性的，因此，相对于遗传能力和选择等简单数量的数据量，关于悖论解决方案的数据量非常缺乏。我们建议解决理论上最重要的解决方案之一，这也是经验研究最少的解决方案之一。如果生存力选择在性状表达前改变了其分布，就会出现“缺失分数问题”。例如，如果本来可以产生高值性状的个体很可能在产生该性状之前死亡（因为相关性状在生命周期的早期阶段的生存力选择），那么这种选择将不会在将可用表型与适合度联系起来的选择分析中被选中：重要的是，在naïve分析中估计的选择将向上偏倚。有许多机会可以解决这个问题，例如，通过联合建模焦点特征的选择和遗传学，以及早期生命活力（即，将生存视为一种特征），或可能影响早期生存的特征。我们将这些机会分为四个层次。所有这些水平都比典型的野外性状选择和遗传研究对数据提出了更高的要求。然而，在许多研究系统中可能实现不同层次的分析。在我们的研究系统中，在圣基尔达的Soay羊种群中，我们能够将所有四个层次的层次应用于一系列特征，特别关注体型和生殖计划。我们将对缺失分数问题的程度进行一系列协调的研究，这将产生一个全面的分析，说明这个关键问题可以在多大程度上改变野外的进化推断。此外，我们还提出(1)理论工作，以解决不同生活史中缺失分数问题的潜在严重性；(2)方法发展，以帮助研究人员（最初包括我们自己！）应用一些最先进的统计方法来解决这个问题；(3)综合回顾，总结现有的理论、方法和关键结果（到本项目结束时，这些结果将大部分来自我们自己的研究）。因此，我们的研究将为进化定量遗传学提供一个全面的进步，并将使该领域开始适当地解决其最大的突出问题之一。

项目成果

Re-identification of individuals from images using spot constellations: a case study in Arctic charr (Salvelinus alpinus).

• DOI: 10.1098/rsos.201768
• 发表时间: 2021-07
• 期刊: Royal Society open science
• 影响因子: 3.5
• 作者: De Bicki IT;Mittell EA;Kristjánsson BK;Leblanc CA;Morrissey MB;Terzić K
• 通讯作者: Terzić K

Correlates of early reproduction and apparent fitness consequences in male Soay sheep.

• DOI: 10.1002/ece3.10058
• 发表时间: 2023-05
• 期刊: Ecology and evolution
• 影响因子: 2.6

MHC class IIa haplotypes derived by high-throughput SNP screening in an isolated sheep population.

• DOI: 10.1093/g3journal/jkab200
• 发表时间: 2021-09-27
• 期刊: G3 (Bethesda, Md.)
• 作者: Dicks KL;Pemberton JM;Ballingall KT;Johnston SE
• 通讯作者: Johnston SE

The diversity of population responses to environmental change

• DOI: 10.1111/ele.13195
• 发表时间: 2019-02-01
• 期刊: ECOLOGY LETTERS
• 影响因子: 8.8
• 作者: Colchero, Fernando;Jones, Owen R.;Gaillard, Jean-Michel
• 通讯作者: Gaillard, Jean-Michel

The dynamics of vegetation grazed by a food-limited population of Soay sheep on St Kilda

• DOI: 10.1111/1365-2745.13782
• 发表时间: 2021-11-02
• 期刊: JOURNAL OF ECOLOGY
• 影响因子: 5.5
• 作者: Crawley, Michael J.;Pakeman, Robin J.;Pemberton, Josephine M.
• 通讯作者: Pemberton, Josephine M.