Application of the Peak Area Ratio of STR Loci to Amelogenin Locus in the Esti-mation of DNA Degradation / 法医学杂志

ABSTRACT

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.