STR基因座与Amelogenin的峰面积比在DNA降解评估中的应用

摘要

目的：研究DNA降解过程中STR基因座与性别基因座Amelogenin（AMEL）峰面积比（STR/AMEL）的变化规律，探讨STR/AMEL值在评估DNA降解程度中的应用。方法取人体髂腰肌组织抽提DNA，分析DNaseⅠ酶人工降解后STR/AMEL值（Penta E/AMEL、Penta D/AMEL、FGA/AMEL）的变化，并分析室外环境自然降解的髂腰肌组织中三者比值的变化。以降解时间为自变量（x），STR/AMEL值为因变量（y），进行回归曲线分析，建立两种条件下三组曲线方程。结果人工降解及自然降解条件下STR/AMEL值与降解时间均呈负相关，一元三次方程能够较好地模拟STR/AMEL值随降解时间的变化规律。人工降解条件下， R2均大于0.99；自然降解条件下，R2均大于0.86。结论 STR/AMEL 值（Penta E/AMEL、Penta D/AMEL、FGA/AMEL）与DNA降解程度呈负相关，有望应用于DNA降解程度的评估。%Objective To explore the change rules of peak area ratio of STR loci to Amelogenin (AMEL) locus (STR/A M EL ), a sex-determ ining gene in DNA degradation, and to evaluate the application of STR/A MEL value in the estim ation of DNA degradation degree. Methods DNA w as extracted from iliopsoas, and the variations of STR/A MEL value (Penta E/AMEL, Penta D/AMEL, FGA/AMEL) w ere analyzed after the artificial degradation w as m ade by DNaseⅠ, and the changes of these three ratios of the iliopsoas naturally degraded in an outdoor environm ent w ere also analyzed. The regression curves w ere analyzed using the periods of DNA degradation and outside the body as the independent variable (x) and the STR/A MEL value as the dependent variable (y) and three curve equations under tw o conditions w ere established. Results B oth under the conditions of artificial and natural degradation, STR/A MEL value had a negative relationship w ith the degradation tim e. The relationship betw een STR/A MEL and degradation tim e can be w ell sim ulated by the cubic function. R2 w as over 0.99 under controlled degradation condition and over 0.86 under natural degradation condition. Conclusion The STR/A MEL value (Penta E/AMEL, Penta D/AMEL , FGA/AMEL ) is negatively related w ith the DNA degradation degree, w hich follow s m athem atical regression m odels strictly, and it m ight be applied to evaluate the DNA degradation degree.