理化因素对人发DNA及其PCR扩增结果的影响

Effects of Some Physical and Chemical factors on Both Human Hair DNA and Results of Sex Determination by PCR

研究了部分理化因素对人发ＤＮＡ及ＰＣＲ性别鉴定结果的影响，人发经不同ｐＨ液处理，ＤＮＡ量均下降。其ＤＮＡ量经ｐＨ１、３、５、７处理２小时减半，ｐＨ１、３处理２４小时检不出，ｐＨ５和７处理２４小时减少和变化不明显，ｐＨ９处理２小时明显减少，处理２４小时检不出。人发经紫外线照射２４小时，ＤＮＡ量不变。人发用７５％乙醇和甲醇浸泡２４小时，ＤＮＡ量均无明显变化。人发经１０％酸性和中性福尔马林浸泡２和２４小时，未检出ＤＮＡ。在１００℃水中煮５和１０分钟，ＤＮＡ量明显下降，５０℃和１００℃直接加热２４小时，ＤＮＡ量不变和略下降。用ＰＣＲ法扩增，除经ｐＨ１１处理２４小时的检材未得到Ａｌｕ和Ｙ产物外，其余检材均获得扩增产物，说明微量ＤＮＡ经扩增后仍可测出扩增产物，供性别鉴定用。

The present study aims at observationof the effects of some physical and chemical factors onboth human hair DNA and eresults of sex determi-nation by PCR. After the hairs were treated withvarying pH solutions,the quantity of the DNA ex-tracted was decreased.High-molecular-weight(HMW)DNA was determined in the gairs treatedwith pH 1,3,5 and 7 solutions for 2 hours,but noDNA was demonstrated by agarose gel electrophoresisin the hairs treated with pH 1 and 3 solution for 24hours, and the quantity of DNA was decreased in thehairs treated with pH 5 for 24 hours. The quantity ofDNA was decreased in the hairs treated with pH 9 for2 hours and no DNA was demonstrated for 24 hours.No DNA was found in the hairs treated with pH 11 for2or 24 hours. No chanRes of DNA were observed inhairs treated with 75%ethanol or methanol for 2 or 24kours and exposed to UV light for 24 hours. No DNAbut RNA was observd in the hairs treated with 10%formalin(pH 7 or pH5)for 2 or 24 hours.The quan-tity of DNA was decreased obviously in the hairs treat-ed in 100℃water for 5 or 10 minutes,The quantity ofDNA was not decreased in the hairs heates at 50℃ for 24 hours,and only little decrease was noted at 100℃for 24 hours. Both fragments of PCR products were obtained inmost hairs except the hairs treatdwith pH11 solutionfor 24 hours. Although no DNA was observed in sometreated hairs,specific bands were detected after PCR.PCR is a very sensitive and specific technique of DNAamplification,which can be used for sex determinationin forensic medicine.