Tassone F, Cheng S, Gardiner K
Eleanor Roosevelt Institute for Cancer Research, Denver, CO 80206.
Am J Hum Genet. 1992 Dec;51(6):1251-64.
Chromosome 21 contains genes relevant to several important diseases. Yeast artificial chromosome (YAC) clones, because they span > 100 kbp, will provide attractive material for initiating searches for such genes. Twenty-two YAC clones, each of which maps to a region of potential relevance either to aspects of the Down syndrome phenotype or to one of the other chromosome 21-associated genetic diseases, have been analyzed in detail. Clones total approximately 6,000 kb and derive from all parts of the long arm. Rare restriction-site maps have been constructed for each clone and have been used to determine regional variations in clonability, methylation frequency, CpG island density, and CpG island frequency versus gene density. This information will be useful for the isolation and mapping of new genes to chromosome 21 and for walking in YAC libraries.
21号染色体包含与几种重要疾病相关的基因。酵母人工染色体（YAC）克隆由于跨度超过100千碱基对（kbp），将为启动此类基因的搜寻提供有吸引力的材料。已经对22个YAC克隆进行了详细分析，每个克隆都定位到与唐氏综合征表型的某些方面或与其他21号染色体相关的遗传疾病之一潜在相关的区域。这些克隆总计约6000 kb，来源于长臂的各个部分。已为每个克隆构建了稀有酶切位点图谱，并用于确定克隆性、甲基化频率、CpG岛密度以及CpG岛频率与基因密度的区域差异。这些信息将有助于新基因在21号染色体上的分离和定位以及在YAC文库中的步移。
