Goddard M E, Hayes B J
University of Melbourne, Attwood, Australia.
J Anim Breed Genet. 2007 Dec;124(6):323-30. doi: 10.1111/j.1439-0388.2007.00702.x.
Genomic selection is a form of marker-assisted selection in which genetic markers covering the whole genome are used so that all quantitative trait loci (QTL) are in linkage disequilibrium with at least one marker. This approach has become feasible thanks to the large number of single nucleotide polymorphisms (SNP) discovered by genome sequencing and new methods to efficiently genotype large number of SNP. Simulation results and limited experimental results suggest that breeding values can be predicted with high accuracy using genetic markers alone but more validation is required especially in samples of the population different from that in which the effect of the markers was estimated. The ideal method to estimate the breeding value from genomic data is to calculate the conditional mean of the breeding value given the genotype of the animal at each QTL. This conditional mean can only be calculated by using a prior distribution of QTL effects so this should be part of the research carried out to implement genomic selection. In practice, this method of estimating breeding values is approximated by using the marker genotypes instead of the QTL genotypes but the ideal method is likely to be approached more closely as more sequence and SNP data is obtained. Implementation of genomic selection is likely to have major implications for genetic evaluation systems and for genetic improvement programmes generally and these are discussed.
基因组选择是标记辅助选择的一种形式，其中使用覆盖整个基因组的遗传标记，以便所有数量性状位点（QTL）与至少一个标记处于连锁不平衡状态。由于通过基因组测序发现了大量单核苷酸多态性（SNP）以及高效对大量SNP进行基因分型的新方法，这种方法已变得可行。模拟结果和有限的实验结果表明，仅使用遗传标记就可以高精度预测育种值，但需要更多验证，特别是在与估计标记效应的群体不同的群体样本中。从基因组数据估计育种值的理想方法是计算给定动物在每个QTL处基因型的育种值的条件均值。这种条件均值只能通过使用QTL效应的先验分布来计算，因此这应该是实施基因组选择所开展研究的一部分。在实践中，通过使用标记基因型而非QTL基因型来近似这种估计育种值的方法，但随着获得更多的序列和SNP数据，可能会更接近理想方法。基因组选择的实施可能会对遗传评估系统以及一般的遗传改良计划产生重大影响，本文对此进行了讨论。
