摘要
建立X染色体短串联重复基因座DXS713 2和DXS680 4的复合扩增系统 ,并用聚丙烯酰胺凝胶电泳和银染技术进行分型 ,调查广东汉族人群该二基因座的多态性。结果发现DXS713 2有 7个等位基因 ,扩增产物的长度在2 76～ 3 0 0bp ;DXS680 4有 6个等位基因 ,扩增产物的长度在 177～ 2 0 1bp。序列分析揭示这两个基因座的重复单位均为四核苷酸重复。由于基因组作图信息显示DXS713 2和DXS680 4之间存在紧密连锁 ,故用家系分析法确定女性的单体型。在 82 7条染色体 (男性 2 11,女性 616)中 ,共发现了 3 3种单体型 ,女性的二倍体数据符合Hardy -Weinberg平衡。基因多样性、多态性信息量和女孩非父排除率分别达 0 9999、0 944 0和 0 9411。对 3 0 8个三联体的家系调查表明这两个基因座符合X染色体共显性遗传 ,未发现突变。结果表明 ,DXS72 3 1和DXS680 4在女孩的亲权认定 ,特别是缺乏双亲检验的案件中有重要的应用价值。
DXS7132 and DXS6804 were amplified by means of multiplex PCR and detected by polyacrylamide gel electrophoresis and silver stain.Population study has been carried out in Guangdong Han Population of South China. DXS7132 exhibited 7 distinguishable alleles ranging from 276～300 bp in size.Number of alleles at DXS6804 was 6 and its range was177～201 bp.Sequencing revealed that their common sequence motifs were tetranucleotide repeats.On the genomic mapping information linkage disequilibrium between DXS7132 and DXS6804 was shown.Female haplotypes were determined by analyzing family trios.In 827(211 males,616 females) chromosomes,total 33 haplotypes were identified.Deviation from Hardy-Weinberg equilibrium was not detected in the female diploid data.Gene diversity,polymorphism information content and probability of exclusion for the two loci were 0 9999,0 9440 and 0 9411,respectively.Investigation in 308 family trios suggested a co-dominant X-linked inheritance and mutations were not found.The result indicates that DXS7132 and DXS7132 will be very useful for paternity testing that involve a female child,especially for the deficiency parents cases.
