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为研究导致Ｙｕｎｎａｎｅｓｅ（Ａγδβ）０－地贫缺失事件的分子机制，并从３′并入序列中搜寻增强子类序列，使用ＥＭＢＬ３为载体构建了一例缺失杂合子的基因组文库，筛选到来源于异常染色体１１并包含Ｇγ珠蛋白基因区６．７ｋｂ序列以及１１．５ｋｂ３′并入序列（即缺失桥片段）的克隆．此１１．５ｋｂ序列在正常染色体中位于β珠蛋白基因约下游６６～７８ｋｂ区域．详细分析了这一区域的限制性内切酶图谱．分析了围绕缺失连接区的ＤＮＡ序列，精确定位缺失的５′端点发生在Ａγ珠蛋白基因上游－１１６～－１１７碱基之间．确定缺失的３′端点处于一个Ｌ１序列内，位于β珠蛋白基因下游～６６ｋｂ，距离Ｃｈｉｎｅｓｅ（Ａγδβ）０－地贫缺失３′端点上游～１２．２ｋｂ的一个ＥｃｏＲⅠ位点上游４１３ｂｐ．围绕５′和３′端点的序列之间无明显同源性，说明这一缺失代表了体内的非同源重组事件．这一重组事件可能由Ｌ１序列介导．缺失３′端点下游序列的克隆分离也为进一步从中搜寻加强子类序列奠定了基础
In order to study the molecular mechanism of deletion of Yunnanese (Aγδβ) 0-thalassemia and to search for enhancer sequences from 3’-incorporation sequences, a genomic library with deletion of heterozygous was constructed using EMBL3 as a vector, Chromosome 11 and contains a 6.7 kb Gγ globin gene region and a 11.5 kb 3 ’incorporation sequence (ie, a deletion of the bridge fragment). This 11.5 kb sequence is located approximately 66-78 kb downstream of the beta globin gene in the normal chromosome. A detailed analysis of the region of the restriction enzyme map. The DNA sequence surrounding the deletion junction was analyzed and the exact 5 ’end of the deletion was found between -116 and -117 bases upstream of the Aγ globin gene. The 3’end of the deletion was identified as a 413 bp upstream of an EcoRI site 12.7 kb upstream of the 3 ’end of the 3’ end of the Chinese (Aγδβ) 0-thalassemia locus within a L1 sequence downstream of the beta globin gene. There is no significant homology between the sequences surrounding the 5 ’and 3’ ends, indicating that this deletion represents a non-homologous recombination event in vivo. This recombination event may be mediated by L1 sequences. Cloning and isolation of the sequences downstream of the deletion 3 ’end also laid the foundation for further searching for enhanced subclass sequences