Department of Biology, Keio University.
Medical Genome Center, Research Institute, National Center for Geriatrics and Gerontology.
Genes Genet Syst. 2023 Nov 21;98(5):267-275. doi: 10.1266/ggs.23-00075. Epub 2023 Oct 13.
The congenic strain, an inbred strain containing a small genomic region from another strain, is a powerful tool to assess the phenotypic effect of polymorphisms and/or mutations in the substituted genomic region. Recent substantial progress in the genetic studies of complex traits increases the necessity of congenic strains and, therefore, a quick breeding system for congenic strains has become increasingly important in model organisms such as mouse and medaka. Traditionally, more than ten generations are necessary to produce a congenic strain. In contrast, a quick method has been reported previously for the mouse, in which the use of genetic markers reduces the required number of backcross generations to about a half that of the traditional method, so that it would take around six generations to obtain a congenic strain. Here, we present an even quicker congenic production system, which takes only about four generations. The system can produce medaka congenic strains having part of the HNI-II (an inbred medaka strain derived from the northern Japanese population, Oryzias sakaizumii) genome in the HdrR-II1 (another inbred strain from the southern Japanese population, O. latipes) background. In this system, the availability of frozen sperm and genotype data of the BC male population makes it possible to start marker-assisted congenic production after obtaining the BC population. Our evaluation revealed that the system could work well to increase the percentage of recipient genome as expected, so that a congenic strain may be obtained in about one year.
同系繁殖系是一种含有另一品系小基因组区域的近交系，是评估被取代基因组区域中多态性和/或突变表型效应的有力工具。近年来，复杂性状的遗传研究取得了重大进展，这增加了对同系繁殖系的需求，因此，快速繁殖同系繁殖系在模式生物（如小鼠和斑马鱼）中变得越来越重要。传统上，需要超过十代才能产生同系繁殖系。相比之下，以前已经报道了一种用于小鼠的快速方法，其中遗传标记的使用将所需的回交代数减少到传统方法的大约一半，因此大约需要六代才能获得同系繁殖系。在这里，我们提出了一种更快的同系繁殖系生产系统，只需要大约四代。该系统可以在 HdrR-II1（另一种来自日本南部种群的近交系，O. latipes）背景下产生具有 HNI-II（一种来自日本北部种群的近交系，O. sakaizumii）基因组部分的斑马鱼同系繁殖系。在该系统中，冷冻精子的可用性和 BC 雄性群体的基因型数据使得在获得 BC 群体后可以开始进行基于标记的同系繁殖系生产。我们的评估表明，该系统可以很好地按预期增加受体基因组的百分比，因此大约一年就可以获得同系繁殖系。
