Investigation of effectiveness of whole genome amplification prior to short tandem repeat analysis for degraded DNA

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K10136
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 58040:Forensics medicine-related
• Research Institution: Tokyo Women's Medical University
• Principal Investigator: Machida Mitsuyo 東京女子医科大学, 医学部, 助教 (60468692)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 全ゲノム増幅法 / DNA損傷 / STR解析

Outline of Final Research Achievements

Short tandem repeat (STR) analysis is prone to failure as DNA is frequently damaged by various environmental factors; hence, increasing the number of starting templates may constitute a feasible approach to improve STR profiling success. One approach to increase the number of DNA templates is whole genome amplification (WGA), however, few studies have demonstrated that WGA can be used on degraded samples in forensics. Therefore, we utilized modified improved primer extension preamplification (mIPEP) prior to STR analysis. For the 5 ng DNA sample on paper, at a DI < 0.2, the number of detectable STRs was greater with mIPEP than without it. The 0.05 ng DNA sample deposited on paper, at when DI was 0.7 or higher, and the 0.05 ng DNA sample deposited on glass, at when DI was 0.4 or higher, exhibited higher numbers of detectable STRs when prepared using mIPEP. These findings suggest that performing mIPEP in accordance with sample DNA condition may lead to increased success of STR analysis.

Free Research Field

法医学

Academic Significance and Societal Importance of the Research Achievements

事件現場等で採取された試料は様々な環境要因によりDNAが変性し、量も限られているため、通常のSTR解析による個人識別が困難になる場合が多い。法医学では量・質共に良い状態ではない試料に対し、個人識別の判定率を高める方法について検討することは重要な課題である。本研究ではSTR解析前に全ゲノム増幅法の1つであるmIPEP処理を行うことで、豊富なDNAの場合は高度な変性試料において、また微量なDNAの場合は軽度の変性試料であれば、STR解析成功率を高めることが明らかになった。つまり、今まで解析困難だった試料がmIPEP処理により解析可能となり、犯罪捜査への貢献が期待される。