1例D7S820基因座三带型等位基因检出报告

Detection of a three-band allele patterns in D7S820 locus

目的探讨华南地区人群亲子鉴定案例中三带型等位基因的频率及特点。方法采用Chelex-100法提取血液DNA,通过复合荧光PCR扩增和毛细管电泳分析2 200个案例(6 000名个体)的DNA-STR(STR:短串连重复序列)基因型。结果在2 200个案例(共6 000名个体)中共检出1例D7S820基因座三带型等位基因,位于父子单亲鉴定案例中儿子的D7S820基因座等位基因8、11和12,父亲D7S820基因座的基因分型为11和12。在本研究中,该D7S820基因座三带型等位基因的频率为1/6 000。Powerples TM16 system荧光标记复合扩增试剂盒对包含D7S820在内的16个STR基因座进行检测,儿子D7S820基因座基因分型8/11/12的电泳峰高和峰面积之比均为1∶1∶1,D7S820基因座三带型等位基因的检测结果与Indentifiler誖试剂盒检测结果相同。结论在本文发现的案例中,父亲的等位基因11和12均遗传给了儿子,导致儿子表现为三带型等位基因。三带型的等位基因在单个STR基因座中很少出现,在分析时应采用不同方法或者试剂盒进行验证,保证鉴定结果的可靠性。

Objective To investigate the genetic frequency and features of three-banded allele in southern China paternity identification cases. Method Blood DNA was extracted using Chelex-100 method. DNA-STR genotype of 2 200 cases（6 000 individuals） were determined and analyzed by multiplex fluorescent PCR amplication and capillary electrophoresis.Results One case was confirmed to have three-band allele locating in D7S820 locus in 2 200 cases（6 000individuals）. The three-band allele located in 8,11 and 12 alleles of D7S820 locus of a child was found in a father-child case. Father’s alleles in D7S820 locus were 11 and 12.The three-banded alleles frequency of D7S820 locus is 1 / 6 000.PowerplexTM16 multiplex fluorescent PCR amplication system detect 16 STR loci including D7S820 locus. The height and area ratio in D7S820 locus of 8, 11 and 12 alleles of child is about 1∶1∶1, the result of three-banded alleles of D7S820 locus is the same as Identifiler kit. Conclusions In this case father’s 11 and 12 alleles passed on to his son leading to the three-band allele pattern. Three-band allele is very rare in single STR locus. To ensure the reliability of analysis results, different methods should be adopted for validation.