A Y‐Chromosomal Haplotype with Two Short Tandem Repeat Mutations*

Abstract:  The male‐specific Y‐chromosomal short tandem repeat (STR) is a useful tool in forensic casework. The Y haplotype comprised of 16 loci, which is amplified simultaneously by AmpFlSTR^® Yfiler^TM PCR kit and provides strong exculpatory evidence in individual identification. We reported a rare Y‐STR profile with a null allele at the DYS448 locus and an off‐ladder allele at the DYS456 locus, when genotyping material from a vaginal swab in an alleged rape case. Sequence analysis revealed that the DYS448 null allele was a true type of null allele because of a total deletion of 11 upstream repeats and 9 bp of the N₄₂ region, and there were numerous primer binding site mutations as well. The amplicon of the DYS456 locus was a small 92‐bp fragment that was off‐ladder, and sequencing analysis showed that there were only 10 repeats (AGAT)₁₀. This Y chromosome haplotype that was comprised of two variations provided helpful evidence for personal identification.     

Evaluation of 96 SNPs in 14 populations for worldwide individual identification

Great advances have been made recently in searching for individual identification single-nucleotide polymorphisms (IISNPs or IDSNPs). Such SNPs as suggested by SNPforID scientists and by Pakstis et al., are promising, although they were selected from older or smaller databases rather than the most recent database. Here, we describe a new computational strategy for developing IDSNPs based on HapMap. We searched through HapMap r27 for SNPs having minor allele frequencies ≥0.30 in all its 11 populations and found more than 1881 qualified SNPs. We examined 96 of them with 183 DNA samples from three Chinese populations using Illumina arrays. The average allele frequency for these 96 SNPs among the three populations was 0.495/0.505, the average number of identical SNP genotypes shared by two individuals among the 14 populations (three Chinese and 11 HapMap) was 37.9, and the random matching probability for two unrelated Hans to match in all 96 genotypes was 9.793 × 10(-39). Thus, most of these 96 SNPs are universally applicable.     

PowerPlex^TM16体系OL等位基因序列分析及命名探讨

目的观察中国汉族人群PowerPlexTM16体系STR基因座分型标准物外等位基因(OL等位基因)的序列组成,探讨其类型及命名。方法应用PowerPlexTM16体系和ABI377或3100遗传分析仪,对10071名中国汉族无关个体的血样DNA进行15个STR基因座的分型,筛选出OL等位基因样本;对该样本进行单基因座扩增、聚丙稀酰胺凝胶电泳、银染显色,获取等位基因条带并再次扩增和测序。结果在11个基因座检见OL等位基因,共32个,频率0.05‰￣4.02‰,各基因座OL等位基因数目1￣9个不等。按其组成分为四类:(1)重复单位完整重复,但重复次数在ladder范围外;(2)不完整重复;(3)侧翼序列个别碱基的插入或缺失;(4)较大片断的缺失。结论OL等位基因类型不一,既有重复次数的变化,也有侧翼序列或核心序列的变化,现有命名原则尚不能反映其组成类型。     

人类D19S40基因座在不同人种中的遗传多态性研究

采用ＰＣＲ技术分析中国汉族、德国人、斯洛伐克人和美国黑人群体Ｄ１９Ｓ４００基因座的遗传多态性及世界三大人种之间的差异。四个群体共调查了６２０人,发现了１１个等位基因,观察到４７种基因型。各群体观察杂合度为：０．７８～０．８８,个人识别机率为：０．９３８５０～０．９６６４。四个群体基因型频率分布符合Ｈａｒｄｙ－Ｗｅｉｎｂｅｒｇ平衡（Ｐ＞０．０５）,三大人种（蒙古人种、高加索人种、美国黑人）之间Ｄ１９Ｓ４００基因座等位基因频率分布存在极显著差异（Ｐ＜０．０１）。结果显示Ｄ１９Ｓ４００基因座在群体遗传学研究和法医学个人识别中有较高应用价值     

Profiler Plus系统在法医学DNA检验中的问题探讨

以Profiler Plus系统生产厂商提供的检验条件,在实际工作中对大规模样品进行了检验分析.结果显示该系统尚存在等位基因丢失、额外等位基因、同一荧光标记不同基因座等位基因重叠公布、罕见等位基因与亚型等非技术操作性问题.对有关样品应用Power Plex1.2,Power Plex16系统进行了检验验证.     

中国汉族群体人类补体C8A多态性

采用免疫沉淀、SDS-聚丙烯酰胺凝胶电泳 (SDS- PAGE)、被动转印及酶免分析 ,研究了人类补体 C8A等位基因频率在成都地区汉族群体中的分布。 12 1份样本被分为 3种常见型 ,即 C8A- A、C8A- B及 C8A- AB,由两个等位共显性基因 C8A * A及 C8A* B控制 ;同时发现了 2个稀有亚型 ,即 A3亚型及新发现的 Ax亚型。等位基因频率为 C8A* A=0 .5 0 83,C8A* B=0 .4835 ,C8A*稀有型 =0 ,0 0 83。说明 C8A多态性在中国群体中具有良好的分布 ,个人识别率(DP)达到 6 1.14% ,可用于法医学个人识别及亲子鉴定     

PCR扩增体系的体积减少对DNA分析的影响

目的探讨PCR扩增体系的体积减少对DNA分析的影响。方法4份样品采用ProfilerPlus试剂盒,在同样条件下,对50μl、25μl、12.5μl、6.25μl四种体积的体系进行扩增,扩增产物分别经ABIPRISMTM310型基因分析仪、ABIPRISMTM377型测序仪、ABIPRISMTM3100型基因分析仪电泳,并经GeneScan3.1基因扫描软件和Genotyper2.5分析软件分析得到实验结果。结果小体积的扩增体系容易出现等位基因的丢失、额外等位基因的产生等现象。结论在检材情况较差时,应该慎用小体积的扩增体系。     

Characterization of deletions in the DYS385 flanking region and null alleles associated with AZFc microdeletions in Koreans

Eight DYS385 allele size discrepancies and six DYS448 null types were detected among 708 Korean men when results of three in-house multiplex short tandem repeat (STR) systems were compared. The systems included both ordinary and reduced size amplicons. Sequence analysis revealed deletion mutations at two sites upstream of the DYS385 core repeats and deletion of the entire DYS448 locus. At DYS385, allele size differences were one or two repeats and were dependent on the primer set used for polymerase chain reaction (PCR) amplification. Location of the primer target sequence in a flanking region of the STR, distal or proximal to the deletion, determined allele size. Two widely used commercial kits amplify DYS385 so as to include the mutable sites. Arrangement analysis of sequence tagged sites demonstrated that the deletion patterns at DYS448 (and DYS464) were associated with arrangements of the azoospermia factor c gene (AZFc). The DYS448 deletion appears relatively frequent in Asians.     

24个Y-STR基因座等位基因频率的群体差异分析

目的调查华东地区汉族无关个体24个Y-STR基因座的群体遗传学多态性,比较华东汉族和广东汉族人群间的群体差异性。方法应用GFS 24Y STR荧光检测试剂盒,对华东地区268名汉族无关个体24个Y-STR基因座进行群体遗传学分析。比较华东汉族和广东汉族人群的等位基因频率,进行群体差异分析。结果华东地区268名汉族无关个体24个Y-STR基因座共检出235个等位基因,267种单倍型,GD值范围为0.564 9~0.966 8。华东汉族和广东汉族人群在DYS622、DYS552、DYS443等12个基因座的等位基因间的差异有统计学意义。结论 GFS 24Y STR荧光检测试剂盒中的Y-STR基因座具有良好的遗传多态性,可应用于父系亲缘关系鉴定。