Cockram James, Mackay Ian
The John Bingham Laboratory, National Institute of Agricultural Botany (NIAB), Cambridge, UK.
Adv Biochem Eng Biotechnol. 2018;164:109-138. doi: 10.1007/10_2017_48.
Fine mapping of quantitative trait loci (QTL) is the route to more detailed molecular characterization and functional studies of the relationship between polymorphism and trait variation. It is also of direct relevance to breeding since it makes QTL more easily integrated into marker-assisted breeding and into genomic selection. Fine mapping requires that marker-trait associations are tested in populations in which large numbers of recombinations have occurred. This can be achieved by increasing the size of mapping populations or by increasing the number of generations of crossing required to create the population. We review the factors affecting the precision and power of fine mapping experiments and describe some contemporary experimental approaches, focusing on the use of multi-parental or multi-founder populations such as the multi-parent advanced generation intercross (MAGIC) and nested association mapping (NAM). We favor approaches such as MAGIC since these focus explicitly on increasing the amount of recombination that occurs within the population. Whatever approaches are used, we believe the days of mapping QTL in small populations must come to an end. In our own work in MAGIC wheat populations, we started with a target of developing 1,000 lines per population: that number now looks to be on the low side. Graphical Abstract.
数量性状基因座（QTL）的精细定位是对多态性与性状变异之间关系进行更详细分子表征和功能研究的途径。它与育种也直接相关，因为它使QTL更容易整合到标记辅助育种和基因组选择中。精细定位要求在发生大量重组的群体中测试标记-性状关联。这可以通过增加作图群体的大小或增加创建群体所需的杂交代数来实现。我们综述了影响精细定位实验精度和功效的因素，并描述了一些当代实验方法，重点介绍了多亲本或多创始群体的使用，如多亲本高世代杂交（MAGIC）和巢式关联作图（NAM）。我们支持MAGIC等方法，因为这些方法明确侧重于增加群体内发生的重组量。无论使用何种方法，我们相信在小群体中定位QTL的时代必将结束。在我们自己对MAGIC小麦群体的研究中，我们最初的目标是每个群体培育1000个株系：现在看来这个数字偏低了。图形摘要。
