Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, West China Second University Hospital, Sichuan University, Sichuan, P. R. China.
Department of Forensic Genetics, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Sichuan, P. R. China.
Electrophoresis. 2021 May;42(9-10):1158-1167. doi: 10.1002/elps.202000318. Epub 2021 Feb 25.
With the discovery of circulating cell-free fetal DNA (cffDNA) in maternal plasma, noninvasive prenatal testing became possible. However, analysis of low-level cffDNA against high background maternal DNA remains complicated and challenging. To circumvent this limitation, selective amplification of cffDNA was used in this study. Two kinds of compound markers (namely DIP-STR and SNP-STR), both based on selective amplification, were used here for targeting fetal DNA. By designing two allele-specific forward primers for DIP-STR and SNP-STR, DNA fragments with different DIP/SNP alleles can be selectively amplified. When analyzing maternal plasma DNA, these markers can selectively target paternally inherited fetal alleles whose DIP/SNP allele was not shared with the mother. In this study, 21 families were studied with six DIP-STRs and 11 SNP-STRs. Fetal DNA was successfully detected across plasma samples for at least one marker. Detection rate varied between DIP-STR and SNP-STR markers, and DIP-STR outperforms SNP-STR. Fetal alleles obtained from maternal plasma were double confirmed by genotyping paternal genomic DNA and fetal genomic DNA from amniocentesis. This study demonstrated that selective amplification strategy can be used to target cffDNA in maternal plasma, which will be a promising method for noninvasive prenatal paternity testing.
随着循环游离胎儿 DNA（cffDNA）在母体血浆中的发现，非侵入性产前检测成为可能。然而，分析低水平的 cffDNA 对抗高背景的母体 DNA 仍然很复杂和具有挑战性。为了规避这一限制，本研究采用了 cffDNA 的选择性扩增。两种复合标记物（即 DIP-STR 和 SNP-STR）都基于选择性扩增，用于靶向胎儿 DNA。通过设计 DIP-STR 和 SNP-STR 的两种等位基因特异性正向引物，可以选择性地扩增具有不同 DIP/SNP 等位基因的 DNA 片段。在分析母体血浆 DNA 时，这些标记物可以选择性地靶向父系遗传的胎儿等位基因，这些等位基因的 DIP/SNP 等位基因与母亲不共享。在本研究中，对 21 个家庭进行了研究，使用了 6 个 DIP-STR 和 11 个 SNP-STR。至少有一个标记物成功地在血浆样本中检测到了胎儿 DNA。DIP-STR 和 SNP-STR 标记物的检测率不同，DIP-STR 优于 SNP-STR。从母体血浆中获得的胎儿等位基因通过对父本基因组 DNA 和羊膜穿刺术获得的胎儿基因组 DNA 的基因分型得到双重确认。本研究表明，选择性扩增策略可用于靶向母体血浆中的 cffDNA，这将是一种很有前途的非侵入性产前亲子鉴定方法。
