MORECULAR GENETICAL INVESTIGATION OF DOMESTIC ANIMALS AND POULTRY USING HIGHLY POLYMORPHIC MICROSATELLITE DNA

为了构建日本鹌鹑遗传连锁图谱，鉴定日本褐牛软骨发育不良的致病基因，并研究日本褐牛群体的遗传特征，本研究利用微卫星DNA富集技术，从日本鹌鹑基因组DNA文库中筛选日本褐牛的微卫星DNA。因此，我们分离出含有CA二核苷酸重复序列的克隆，但是这些克隆中的大多数的二核苷酸重复序列被另一个序列中断。这些中断的二核苷酸重复序列不太可能是多态性的，因此不能被用作标记locites.In一个特定的人口的日本褐牛，软骨发育不良性侏儒症是作为一种常染色体隐性遗传性状遗传。利用2200个牛微卫星标记和一个父系半同胞家系，包括48个患病和28个正常动物，我们调查的位点之间的连锁负责牛软骨发育不良和微卫星位点。因此，我们将该基因定位在牛6号染色体的特定区域。牛6号染色体的区域与FGFR3基因所在的人和小鼠染色体的区域同源。由于该基因是已知的负责人类软骨发育不良，FGFR 3基因是一个候选基因的牛软骨发育不良。大约50%的微卫星标记在群体中具有多态性，但在牛中是纯合状态。这些纯合基因座的很大一部分被发现定位在染色体的特定区域。这些结果表明，微卫星位点可作为研究家畜群体遗传特征的一个有用标记。

The aims of the present study are to construct genetic linkage maps of the Japanese quail, to identify gene responsible for chondrodysplasia of Japanese brown cattle, and to characterize genetic feature of the particular population of Japanese brown cattle.To isolate microsatellite DNA of Japanese quail, microsatellite enriched genomic DNA library was screened with dinucliotide repeats. Consequently, we isolate clones containing CA dinucleotide repeats, but the dinucleotide repeats of most of these clone are interrupted by another sequences. These interrupted dinucleotide repeats are not likely to be polymorphic and thus could not be used as marker loci.In a particular population of Japanese brown cattle, a chondrodysplastic dwarfism is inherited as an autosomal recessive trait. By using 2200 bovine microsatellite markers and a paternal half-sib pedigree including 48 affected and 28 normal animals, we investigated linkage between the locus responsible for the bovine chondrodysplasi and microsatellite loci. Consequently, we mapped the locus on a particular region of bovine chromosome 6. The region of the bovine chromosome 6 is homologous to regions of human and mouse choromosomes on which FGFR3 gene is localized. Since this gene is known to be responsible for human chondrodysplasia, the FGFR3 gene is a candidate gene for the bovine chondrodysplasia.Genome wide scanning of the 5 cattle obtained from a particular population of Japanese brown cattle were performed by using microsatellite markers. About 50% of the microsatellite markers, which are polymorphic in the population, were homozygous condition in the cattle. The significant portion of these homozygous loci were revealed to localize on particular region of chromosomes. These findings suggest that the microsatellite loci could be a useful markers for investigating the genetic feature of populations of domestic animals.