Discovery unbalanced DNA mixtures and evaluation mixing ratio via a droplet digital PCR method.

Autor: Fu X; Department of Forensic Medicine, School of Basic Medical Sciences, Central South University, No172. Tongzipo Road, Changsha, 410013, Hunan PR, China., Li X; Department of Forensic Medicine, School of Basic Medical Sciences, Xinjiang Medical University, Urumqi, 830017, Xinjiang PR, China., Wang Y; Department of Forensic Medicine, School of Basic Medical Sciences, Central South University, No172. Tongzipo Road, Changsha, 410013, Hunan PR, China., Xie M; Department of Obstetrics, Xiangya Hospital Central South University, Changsha, China., Wen D; Department of Forensic Medicine, School of Basic Medical Sciences, Central South University, No172. Tongzipo Road, Changsha, 410013, Hunan PR, China., Tang X; Department of Forensic Medicine, School of Basic Medical Sciences, Central South University, No172. Tongzipo Road, Changsha, 410013, Hunan PR, China., Wang C; Department of Forensic Medicine, School of Basic Medical Sciences, Central South University, No172. Tongzipo Road, Changsha, 410013, Hunan PR, China., Jia H; Department of Forensic Medicine, School of Basic Medical Sciences, Central South University, No172. Tongzipo Road, Changsha, 410013, Hunan PR, China., Liu Y; Department of Forensic Medicine, School of Basic Medical Sciences, Central South University, No172. Tongzipo Road, Changsha, 410013, Hunan PR, China., Chen S; Department of Forensic Medicine, School of Basic Medical Sciences, Central South University, No172. Tongzipo Road, Changsha, 410013, Hunan PR, China., Wang Y; Department of Forensic Medicine, School of Basic Medical Sciences, Central South University, No172. Tongzipo Road, Changsha, 410013, Hunan PR, China., Zha L; Department of Forensic Medicine, School of Basic Medical Sciences, Central South University, No172. Tongzipo Road, Changsha, 410013, Hunan PR, China., Li J; Department of Forensic Medicine, School of Basic Medical Sciences, Central South University, No172. Tongzipo Road, Changsha, 410013, Hunan PR, China. 549529389@qq.com.
Jazyk: angličtina
Zdroj: International journal of legal medicine [Int J Legal Med] 2024 Aug 28. Date of Electronic Publication: 2024 Aug 28.
DOI: 10.1007/s00414-024-03306-z
Abstrakt: Background: Small amounts of DNA from a perpetrator collected during crime-scene investigations can be masked by large amounts of DNA from the victim. These samples can provide important information for the perpetrator's conviction. Short tandem repeat (STR) detection system is not sensitive enough to detect trace amounts of minor components in unbalanced mixed DNA. We developed a system using droplet digital polymerase chain reaction (ddPCR) capable of discovering trace components and accurately determining the ratio of mixed DNA in extremely unbalanced mixtures.
Methods: The non-recombining regions of the X chromosome and Y chromosome were quantified in the DNA of male and female mixtures using duplex ddPCR. Absolute quantification of low-abundance portions of trace samples and unbalanced mixtures was done using different mixing ratios.
Results: The ddPCR system could be used to detect low-abundance samples with < 5 copies of DNA components in an extremely unbalanced mixture at a mixing ratio of 10000:1. The high sensitivity and specificity of the system could identify the mixing ratio of mixed DNA accurately.
Conclusions: A ddPCR system was developed for evaluation of mixed samples of male DNA and female DNA. Our system could detect DNA quantities as low as 5 copies in extremely unbalanced mixed samples with good specificity and applicability. This method could assist forensic investigators in avoiding the omission of important physical evidence, and evaluating the ratio of mixed male/female trace samples.
(© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
Databáze: MEDLINE
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