Development of experimental animals and functional genomics based on BAC library derived from Japanese mouse subspecies, MSM/Ms.

MSM/Ms是源自日本野生小鼠Mus musculus molossinus的近交系。为了获得MSM/Ms的基因组信息，我们构建了一个覆盖MSM/Ms基因组的细菌人工染色体文库。对176，256个BAC克隆插入片段的两端进行了测序，并将62，988个BAC末端序列（BES）对定位到C57 BL/6 J基因组上，覆盖了总基因组的89%。利用北京谱仪图谱数据，我们建立了一个基于计算机的克隆筛选系统。MSM/Ms和C57 BL/6 J序列的比较揭示了489，200个候选单核苷酸多态性（SNP）。总的核苷酸替换率高达0.0096。C57 BL/6 J基因组中SNP的分布沿着不均匀：大部分基因组显示出高SNP率，只有5.2%的基因组显示出极低的SNP率;这些序列很可能来源于molossinus基因组。据信，molossinus亚种对普通实验室品系小鼠的基因组构成有重要贡献，尽管它们的大部分基因组来自西欧的M. M.阿提库斯因此，关于molossinus基因组的信息不仅对于涉及molossinus的遗传研究是必不可少的，而且对于常见实验室菌株的特征也是必不可少的。利用MSM/Ms和用于转基因的实验室菌株之间经常发现的SNP，我们可以检测BAC克隆中所含转基因的表达。我们成功地挽救了小鼠17号染色体上t^突变的胚胎致死表型<w5>，并证明了MSM BAC转基因在小鼠功能基因组分析中的实用性。

MSM/Ms is an inbred strain derived from the Japanese wild mouse, Mus musculus molossinus. In order to gain genomic information from MSM/Ms, we constructed an arrayed bacterial artificial chromosome (BAC) library from male MSM/Ms genomic DNA, covering genome equivalent. Both ends of 176,256 BAC clone inserts were sequenced, and 62,988 BAC-end sequence (BES) pairs were mapped onto the C57BL/6J genome, covering 89% of the total genome. Taking advantage of the BES map data, we established a computer-based clone screening system. Comparison of the MSM/Ms and C57BL/6J sequences revealed 489,200 candidate single nucleotide polymorphisms (SNPs). The overall nucleotide substitution rate was as high as 0.0096. The distribution of SNPs along the C57BL/6J genome was not uniform : The majority of the genome showed a high SNP rate, and only 5.2% of the genome showed an extremely low SNP rate; these sequences are likely derived from the molossinus genome.It is believed that subspecies molossinus has contributed substantially to the genome constitution of common laboratory strains of mice, although the majority of their genome is derived from the west European M. m. domesticus. Information on the molossinus genome is thus essential not only for genetic studies involving molossinus but also for characterization of common laboratory strains.We also used these BAC clones for making transgenic animals. We could detect expression of transgenes contained in the BAC clone taking advantage of SNPs frequently found between MSM/Ms and laboratory strain used for transgenesis. We could successfully rescue embryonic lethal phenotype of t^<w5> mutation mapped on mouse chromosome 17, and proved utility of MSM BAC transgenesis in functional genomic analyses in mice.