...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Genetica >Analysis and implications of mutational variation
【24h】

Analysis and implications of mutational variation

机译：突变变异的分析及其含义

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Variation from new mutations is important for several questions in quantitative genetics. Key parameters are the genomic mutation rate and the distribution of effects of mutations (DEM), which determine the amount of new quantitative variation that arises per generation from mutation (V M ). Here, we review methods and empirical results concerning mutation accumulation (MA) experiments that have shed light on properties of mutations affecting quantitative traits. Surprisingly, most data on fitness traits from laboratory assays of MA lines indicate that the DEM is platykurtic in form (i.e., substantially less leptokurtic than an exponential distribution), and imply that most variation is produced by mutations of moderate to large effect. This finding contrasts with results from MA or mutagenesis experiments in which mutational changes to the DNA can be assayed directly, which imply that the vast majority of mutations have very small phenotypic effects, and that the distribution has a leptokurtic form. We compare these findings with recent approaches that attempt to infer the DEM for fitness based on comparing the frequency spectra of segregating nucleotide polymorphisms at putatively neutral and selected sites in population samples. When applied to data for humans and Drosophila, these analyses also indicate that the DEM is strongly leptokurtic. However, by combining the resultant estimates of parameters of the DEM with estimates of the mutation rate per nucleotide, the predicted V M for fitness is only a tiny fraction of V M observed in MA experiments. This discrepancy can be explained if we postulate that a few deleterious mutations of large effect contribute most of the mutational variation observed in MA experiments and that such mutations segregate at very low frequencies in natural populations, and effectively are never seen in population samples. Keywords Mutation - Quantitative traits - Fitness - Distribution of effects
机译：新突变的变异对于定量遗传学中的几个问题很重要。关键参数是基因组突变率和突变效应的分布（DEM），它们确定了由突变（V M ）每代产生的新的定量变化量。在这里，我们回顾了有关突变累积（MA）实验的方法和经验结果，这些实验和实验结果揭示了影响定量性状的突变特性。出乎意料的是，大多数来自MA系实验室检测的适应性状数据都表明DEM是形式上的扁桃体（即脂蛋白比指数分布少得多），并且暗示大多数变异是由中度到大型效应的突变产生的。这一发现与MA或诱变实验的结果形成了鲜明对比，在MA或诱变实验中，可以直接检测DNA的突变变化，这意味着绝大多数突变具有非常小的表型效应，并且分布具有瘦素形式。我们将这些发现与最近的方法进行比较，这些方法试图根据比较人群样本中假定的中性位点和选定位点的核苷酸多态性的频谱来推断适合的DEM。当将其应用于人类和果蝇的数据时，这些分析还表明DEM具有很强的瘦素体能力。但是，通过将所得的DEM参数估计值与每个核苷酸突变率的估计值结合起来，预测的适合度的V M 只是观察到的V M 的一小部分在MA实验中。如果我们假设在MA实验中观察到的大多数突变变异是由一些影响较大的有害突变造成的，并且这种突变在自然种群中以极低的频率隔离，并且在种群样本中从未见过，则可以解释这种差异。关键词突变-数量性状-适合度-效应分布

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号