Data and theory point to mainly additive genetic variance for complex traits.
Data and theory point to mainly additive genetic variance for complex traits.
复制标题
DOI：
10.1371/journal.pgen.1000008
复制
发表时间：
2008-02-29
期刊：
影响因子：
4.5
通讯作者：
Visscher PM
中科院分区：
文献类型：
--
作者：
Hill WG;Goddard ME;Visscher PM
复杂性状的加性变异和非加性变异的相对比例在进化生物学、医学和农业中具有重要意义。我们解决了关于非加性遗传变异的贡献的长期争议和悖论，即关于生物途径和基因网络的知识意味着上位性是重要的。然而，一系列性状和物种的经验数据表明，大多数遗传差异是累加的。我们对遗传方差分量的实证研究的证据进行了评估，发现加性方差通常占总遗传方差的一半以上，而且往往接近100%。基于中性和其他群体遗传模型下的等位基因频率分布，我们提出了新的理论结果，这说明了为什么即使在基因作用水平上存在非加性效应也是如此。我们的结论是，在基因水平上的相互作用不太可能在变异水平上产生太多的相互作用。由于基因的加性、显性和互作效应，数量性状或复杂性状的遗传变异可以分为许多成分。最重要的是加性遗传方差，因为它决定了亲缘关系的大部分相关性以及通过自然选择或人工选择发生遗传变化的机会。从文献回顾和对人类双胞胎数据的总结分析中，我们发现总遗传方差的很高比例，通常超过一半，是相加的。这是令人惊讶的，因为在最近的QTL分析中，有许多潜在的基因效应在座位内和座位之间存在交互作用。我们证明，在中性突变的标准模型下，基因频率呈U型分布，最接近0或1，无论单个基因座的显性或上位性大小，都会有很高比例的加性方差。我们还表明，该模型与正在进行选择的群体的观察和对F2群体的QTL分析结果是一致的。
The relative proportion of additive and non-additive variation for complex traits is important in evolutionary biology, medicine, and agriculture. We address a long-standing controversy and paradox about the contribution of non-additive genetic variation, namely that knowledge about biological pathways and gene networks imply that epistasis is important. Yet empirical data across a range of traits and species imply that most genetic variance is additive. We evaluate the evidence from empirical studies of genetic variance components and find that additive variance typically accounts for over half, and often close to 100%, of the total genetic variance. We present new theoretical results, based upon the distribution of allele frequencies under neutral and other population genetic models, that show why this is the case even if there are non-additive effects at the level of gene action. We conclude that interactions at the level of genes are not likely to generate much interaction at the level of variance. Genetic variation in quantitative or complex traits can be partitioned into many components due to additive, dominance, and interaction effects of genes. The most important is the additive genetic variance because it determines most of the correlation of relatives and the opportunities for genetic change by natural or artificial selection. From reviews of the literature and presentation of a summary analysis of human twin data, we show that a high proportion, typically over half, of the total genetic variance is additive. This is surprising as there are many potential interactions of gene effects within and between loci, some revealed in recent QTL analyses. We demonstrate that under the standard model of neutral mutation, which leads to a U-shaped distribution of gene frequencies with most near 0 or 1, a high proportion of additive variance would be expected regardless of the amount of dominance or epistasis at the individual loci. We also show that the model is compatible with observations in populations undergoing selection and results of QTL analyses on F2 populations.
登录
查看更多内容
影响因子：
4.5
作者：
Evans, David M.;Marchini, Jonathan;Morris, Andrew P.;Cardon, Lon R.
通讯作者：
Cardon, Lon R.
DOI：
10.1098/rspb.1997.0027
发表时间：
1997-02-22
影响因子：
4.7
作者：
Fowler, K;Semple, C;Partridge, L
通讯作者：
Partridge, L
影响因子：
3.3
作者：
Cheverud, JM;Routman, EJ
通讯作者：
Routman, EJ
影响因子：
3.8
作者：
Kearsey, MJ;Pooni, HS;Syed, NH
通讯作者：
Syed, NH
DOI：
10.1017/s0016672304006779
发表时间：
2004-06-01
期刊：
GENETICAL RESEARCH
影响因子：
--
作者：
Carlborg, R;Hocking, PM;Haley, CS
通讯作者：
Haley, CS