earticle

영어

In many case, large amount of female DNA mixed with small amount of male DNA in crime scene evidence. When we analyze Autosomal STR profile of those samples, we only get female STR profiles. However, if we analyze Y-STR profile, we can get male Y-STR profiles from that sample. We do not have any scientific explanation for that result. In this study, we want to find the male to female DNA mixture ratio that male Autosomal STR cannot be detected and also Y-STR can be detected even though male Autosomal STR is not detected. At first, we determine the amount of male DNA (63pg) that we can detect both male Autosomal STR and YSTR. After that, we add female DNA in various different ratios (1:0, 1:1, 1:5, 1:10, 1:10), than we compare each samples' Autosomal STR profiles. We can detect both male and female Autosomal STR form the sample that male to female DNA ratio is 1:5. We can notice the male Autosomal STR presence from ratio 1:10 samples, but we cannot get accurate male Autosomal STR profile. Above ratio 1:10, only female Autosomal STRs are detected from samples. We can also get accurate Y-STR profiles from ratio 1:2000 sample. We can get partial Y-STR profiles form ratio 1:4000 sample and above that, Y-STRs are not detected from samples. We collect and test samples from 50 cases that female Autosomal STR is detected however, only Y-STR is detected for male. From these cases, we find that we can detect Y-STR from ratio 1:460 and the amount of male DNA is 63pg.