Peripolli E, Munari D P, Silva M V G B, Lima A L F, Irgang R, Baldi F
Departamento de Zootecnia, Faculdade de Ciências Agrárias e Veterinárias, UNESP Univ Estadual Paulista Júlio de Mesquita Filho, Jaboticabal, 14884-900, Brazil.
Departamento de Ciências Exatas, Faculdade de Ciências Agrárias e Veterinárias, UNESP Univ Estadual Paulista Júlio de Mesquita Filho, Jaboticabal, 14884-900, Brazil.
Anim Genet. 2017 Jun;48(3):255-271. doi: 10.1111/age.12526. Epub 2016 Dec 1.
This review presents a broader approach to the implementation and study of runs of homozygosity (ROH) in animal populations, focusing on identifying and characterizing ROH and their practical implications. ROH are continuous homozygous segments that are common in individuals and populations. The ability of these homozygous segments to give insight into a population's genetic events makes them a useful tool that can provide information about the demographic evolution of a population over time. Furthermore, ROH provide useful information about the genetic relatedness among individuals, helping to minimize the inbreeding rate and also helping to expose deleterious variants in the genome. The frequency, size and distribution of ROH in the genome are influenced by factors such as natural and artificial selection, recombination, linkage disequilibrium, population structure, mutation rate and inbreeding level. Calculating the inbreeding coefficient from molecular information from ROH (F ) is more accurate for estimating autozygosity and for detecting both past and more recent inbreeding effects than are estimates from pedigree data (F ). The better results of F suggest that F can be used to infer information about the history and inbreeding levels of a population in the absence of genealogical information. The selection of superior animals has produced large phenotypic changes and has reshaped the ROH patterns in various regions of the genome. Additionally, selection increases homozygosity around the target locus, and deleterious variants are seen to occur more frequently in ROH regions. Studies involving ROH are increasingly common and provide valuable information about how the genome's architecture can disclose a population's genetic background. By revealing the molecular changes in populations over time, genome-wide information is crucial to understanding antecedent genome architecture and, therefore, to maintaining diversity and fitness in endangered livestock breeds.
本综述提出了一种更广泛的方法来实施和研究动物群体中的纯合子片段（ROH），重点在于识别和表征ROH及其实际意义。ROH是个体和群体中常见的连续纯合片段。这些纯合片段能够深入了解群体的遗传事件，使其成为一种有用的工具，可提供有关群体随时间的人口统计学演变的信息。此外，ROH还提供了有关个体间遗传相关性的有用信息，有助于降低近亲繁殖率，并有助于揭示基因组中的有害变异。基因组中ROH的频率、大小和分布受自然和人工选择、重组、连锁不平衡、群体结构、突变率和近亲繁殖水平等因素影响。根据ROH的分子信息计算近亲繁殖系数（F），在估计自交率以及检测过去和近期的近亲繁殖效应方面，比根据系谱数据估计（F）更为准确。F的更好结果表明，在缺乏系谱信息的情况下，F可用于推断群体的历史和近亲繁殖水平信息。优良动物的选择产生了巨大的表型变化，并重塑了基因组各个区域的ROH模式。此外，选择增加了目标基因座周围的纯合性，并且有害变异在ROH区域中出现得更为频繁。涉及ROH的研究越来越普遍，并提供了有关基因组结构如何揭示群体遗传背景的宝贵信息。通过揭示群体随时间的分子变化，全基因组信息对于理解先前的基因组结构至关重要，因此对于维持濒危家畜品种的多样性和适应性也至关重要。
