摘要
为研究高度变异的STR基因座核心序列结构 ,对广州汉族人群突变率较高的D12S391和D11S5 5 4基因座等位基因进行了序列分析。结果显示D12S391基因座核心序列结构为 (AGAT) 8～ 17(AGAC) 6～ 10 (AGAT) 0～ 1,其较小片段等位基因 (15～ 18)仅表现为第 1个重复单位 (AGAT)数目的变异 ,而较大片段等位基因 (19～ 2 7) ,可表现为第 2或第 3个重复单位数目的变异。发现有 4种新的等位基因 ,分别命名为 2 2″、2 3″、2 4 和 2 7。D11S5 5 4基因座核心序列结构更复杂 ,有 5种核心序列 ,其中 3种具有相同的基本结构 (AAAGG) (AAAG) 4 (AAAGG) 2～ 3 (AAAG) 13～ 19。其大片段等位基因(2 19～ 2 4 9)核心序列结构中 ,既有四核苷酸重复 ,还有五核苷酸重复 ,以及单个硷基的变异、硷基插入或缺失。两基因座均存在序列异质性。结果表明D12S391和D11S5 5 4基因座属复杂重复类型 ,为其准确分型增加了难度 ,首先需建立相应群体的等位基因分型标准物。
To study the core sequence of the hypervariable short tandom repeats,we sequenced the alleles of D12S391 and D11S554 loci which show high mutation rate in Guangzhou Han population.The D12S391 locus has the basic sequence structure (AGAT)_ 8～17 (AGAC)_ 6～10 (AGAT)_ 0～1 .The smaller alleles (15～18) at D12S391 locus have variation limited to the number of the first repeat (AGAT),whereas the larger alleles (19～27)have more complex variation in the number not only of the first repeat but also of the other two repeats (AGAC) and (AGAT).Four new alleles named 22″?23″?24and 27 respectively were found.The D11S554 locus has more complex core sequence classified into five sequence types.Three of them have the same basic sequence structure (AAAGG)(AAAG)_4(AAAGG)_ 2～3 (AAAG)_ 13～19 .In the larger alleles (219～249),there are four and five nucleotide repeats.Some of the larger alleles(219～249) have one base variation,bases insert or deletion.The two loci all have sequence heterogeneity.Our results indicated that the two loci D12S391 and D11S554 belong to complex repeats and this adds difficulty to their correctly typing.It is essential to construct allelic ladder in each population.
基金
中山医科大学"2 11工程"重点学科建设课题基金赞助项目 (4 2 0 90 0 8)~~
