24个Y-STR检测体系的法医学验证及多态性调查

发布时间：2018-04-11 03:38

  本文选题：Y染色体 + STR　； 参考：《南方医科大学》2017年博士论文

【摘要】：Y-STR位于Y染色体的非重组区,是Y染色体上的高多态性遗传标记,在有丝分裂中以单倍型的形式由父亲遗传给儿子,是父系亲权鉴定和男女混合样本检验的重要遗传标记,也是群体遗传学和家族谱系研究的重要工具。国内研发的Y-STR检测体系所包含的基因座多,在中国人群中多态性更好,但很多体系缺乏法医学验证和人群遗传调查。本研究按照法医荧光标记STR复合扩增检测体系的验证流程,对AGCU Y24荧光检测体系进行了法医学验证,发现AGCU Y24能检出0.125ng男性DNA样本的完整分型,对0.065ng的男性DNA样本能检出大部分等位基因;体系对PCR抑制剂的耐受性很高,能够耐受25 ng/μl的鞣酸、或50 ng/μl的腐植酸、或160μmol/L血红素;体系PCR反应组分浓度变化的冗余度比较大,除在引物和反应液浓度降低50%的情况下出现等位基因丢失外,组分变化的其它情况下均能对样本进行完整分型;在对0.5ng男性DNA样本扩增28至32个循环时,发现28个循环下也能获得峰较低的完整分型,循环次数的增加能明显提高等位基因峰高,扩增平衡性受影响不大,说明体系能通过适当增加PCR循环数,提高对微量检材的检验能力。在男男混合物测试中,当弱势供体与优势供体的DNA量比例大于1:4时,AGCU Y24能够很好地将混合物中弱势供体的基因型检验出。在男女混合样本测试中,本研究发现,在第一阶段退火温度为60℃的条件下,AGCU Y24体系比较容易受女性成分干扰,会产生固定的非特异性峰;本研究在将第一阶段退火温度优化为63 ℃,发现AGCU Y24能对500ng女性DNA与0.5ng男性DNA的混合样本进行准确分型,而体系灵敏度变化不大。总之,本文通过对AGCU Y24荧光检测体系进行了法医学验证,认为AGCU Y24体系能满足法医应用的要求。本研究应用AGCUY24和GFS24Y试剂盒,检测了汉族、广西瑶族、广西壮族、广西仡佬族、广西苗族、广西毛南族、广西京族等7个民族群体共2019名无关男性个体的40个Y-STR,共检测出337个等位基因和三个多拷贝基因座的142个单体型,观察到1938个特有单倍型、1863个唯一单倍型,总群体的PD值达0.9994。在总人群中GD值最大的是DYS385ab,为0.9643;最小的是DYS438(0.4102)。AGCUY24比YfilerTM体系多的6个基因座多态性高,更能满足法医DNA检验的需求。40个Y-STR在汉族的多态性最高,而在广西瑶族的多态性最低。本研究认为在应用Y-STR进行法医DNA鉴定时,要重视样本所属个体的民族背景信息,科学出具鉴定意见。在人群遗传分析中,广西瑶族与其它人群的遗传距离最远,可能和采样人群居住在山区有关。除瑶族以外的七个南方民群体(汉族、广东汉族、仡佬族、苗族、京族、壮族、毛南族)之间遗传距离明显比北方群体之间更近。在系统进化树上,汉族、广东汉族、仡佬族、苗族、京族、壮族、毛南族等7个南方群体可以视为一支,而藏族、蒙古族、回族、维吾尔族可以视为另一支,而广西瑶族和朝鲜族各单独形成分支。
[Abstract]:Y-STR, located in the non-recombination region of Y chromosome, is a highly polymorphic genetic marker on Y chromosome. It is inherited from father to son in the form of haplotype in mitosis. It is an important genetic marker for paternity test and mixed sample test.It is also an important tool for the study of population genetics and family genealogy.The Y-STR detection system developed in China contains more loci and is more polymorphic in Chinese population, but many systems lack forensic medical verification and population genetic investigation.In this study, according to the verification procedure of forensic fluorescence labeled STR multiplex amplification detection system, the AGCU Y24 fluorescence detection system was verified by forensic medicine. It was found that AGCU Y24 could detect the complete typing of 0.125ng male DNA samples.Most of the alleles could be detected in male DNA samples of 0.065ng; the system had high tolerance to PCR inhibitors and could tolerate tannic acid of 25 ng/ 渭 l, humic acid of 50 ng/ 渭 l, or heme of 160 渭 mol/L.With the exception of alleles lost in the case of 50% reduction in primer and reaction solution concentration, the samples could be completely typed when the components changed, and when 28 to 32 cycles were amplified from 0.5ng male DNA samples,It was found that the complete genotyping with lower peaks could also be obtained under 28 cycles. The increase of cycle times could significantly increase the peak height of alleles, and the amplification equilibrium was not affected, indicating that the system could increase the number of PCR cycles properly.Improve the inspection ability of trace materials.In the test of male and male mixture, when the ratio of DNA of weak donor to dominant donor was greater than 1:4, AGCU Y24 could well test the genotype of weak donor in mixture.In the test of mixed samples of men and women, we found that AGCU Y24 system is more susceptible to female interference under the first stage annealing temperature of 60 鈩，

本文编号：1734284