The Comparative Study Of The DNATyperTM15and IdentifilerTM Kits In The Applications Of Forensic Medicine

DNA inspection technology plays an increasinglysignificant role since its application in investigating criminal cases in China. Withthe development of DNA testing technology, our country began to carry out the construction of DNA database since2004. At the same time of the dramatic rise of DNA database, thenumber of the database samples keeps increasing significantly. To date, the total capacity of the national DNA database is more than10million bars. Material evidence identifying center in ministry of public security has successfully developed domestic DNATyperTM15kit during "Fifteen " Plan in order to reduce the cost of inspection imported abroad. Because most of the DNA database choose bloodstain as database building of samples and it is with high rate of DNA, domestic kit has replaced imported reagent in the construction of the DNA database around the country and has been widely used. However, staffs in DNA laboratory choose import reagents for inspection, as the difficulties in daily inspection. Therefore, domestic reagent has been confined to the DNA database construction, but not in the case of inspection.At present, many types of cases are accepted by the public security organs in daily, which from murder, rape, theft to the civil and criminal cases involving the paternity test home, rape pregnancy, anti-trafficking and the identity of the nameless corpse. IdentifilerTM kit produced by ABI, after years of use, because of the results are stable, reliable, it’s testing capacity is widely recognized and commonly used in our daily cases test.This article use DNATyperTM15and IdentifilerTM kits on a variety of daily cases samples parallel control study of the various indicators, thus evaluating the range of applications of DNATyperTM15kit in everyday cases.1, DNATyperTM15and IdentifilerTM kits genetic survey in Shenzhen in the Han peopleFour thousand one hundred and forty five samples have been chosen randomly from Shenzhen DNA database, through the inspection of17STR loci by DNATyperTM15and IdentifilerTM kits, thenallele frequency was observed and calculated including heterozygosity (H), probability of discrimination power (DP), polymorphism information contents (PIC), excluding probability of paternity (PE), probability of matching (Pm), cumulative probability of exclusion (CPE), cumulative probability of discrimination (CDP) and cumulative matching probability. Application of Domestic DNATyperTM15and IdentifilerTM kits were also evaluated.On the basis of genetics survey of the4145samples in Shenzhen area, three loci of TH01, THOX and D19S433tested by IdentifilerTM kit were found that number of alleles in TH01、TPOX and D19S433loci were8、9and15respectively among the32alleles being checked out, and the three genetic loci probability of discrimination power are0.8473、0.7845and0.9449respectively, and the excluding probability of paternity are0.3892、0.3061and0.6134. Hence, the effect of TH01and THOX loci in the whole kit is very limited. On the other hand, D6S1043and Penta E loci, which are well distributed in ethnic Han, are tested by DNATyperTM15kit. Two genes were detected39alleles, respectively for18and21, and the probability of discrimination power are0.9708and0.9861, and the excluding probability of paternity are0.7297 and0.8099respectively. CPE of the14STR tested by DNATyperTM15kit is0.999999383, accumulated matching probability is1.69×10-18, and CDP is0.99999999999999999831; CPE of the15STR tested by IdentifilerTM kit is0.999998032, accumulated matching probability is7.55×10-18, and CDP is0.99999999999999999245.2. Comparative analysis of inspection results in vary samples by DNATyperTM15and IdentifilerTM kitsIn this research, parallel controlled trial was carried out by using DNATyperTM15and IdentifilerTM kits including9947standard product of gradient dilution,480pieces of routine inspection material samples, trace inspection material sample, pollution inspection material sample, and degradation inspection material sample. Extraction, STR loci amplified, the detection, classification, and the data storing of the samples are all under the same condition. On the basis of comparing sensitivity of DNATyperTM15and IdentifilerTM kits, detection rate of the four types of samples, PHR, and consistency of allele’s classification results, the inspection effect of domestic DNATyperTM15kit was evaluated.Among the inspection of the standard product of9947A in its template quantity including2.0ng,1.0ng,0.5ng,0.25ng,0.125ng and0.0625ng in gradient dilute concentrations, the sample of template quantity above0.25ng can be successfully tested by DNATyperTM15and IdentifilerTM kits.Among480pieces of sample material inspection including inspection of conventional materials, trace inspection materials, polluted materials, anddegradative materials,439pieces were identified by DNATyperTM15kit with91.5%relevanceratio, while444pieces were indentified by IdentifilerTM kit with92.5%relevanceratio.439pieces of samples in total have been identified in which the Loci is85and74respectively under the condition of PHR≤0.5; in the same sample inspection, alleles classification results are all agree with the same loci tested by the two kits. Using McNemar testing method, two kinds of kit detection rate and the alleles peak height ratio P value were0.227and0.108(>0.1), and Kappa coefficient were0.845and0.751respectively, indicating that two kind of kit detection rate and the alleles peak were no significantaly statisticaldifference, and has a very high coincidence degree. Two kinds of kit have identified436cases of sample, so the other44pieces of sample were detected for PCR quantitative, and all samples being tested in which the DNA content are below0.22ng.3. Comparative analysis of DNATyperTM15and identifilerTM kits in the cases of paternitytestIn this research, comparison of RCP of30cases of parents (triplet) and30cases of single parent (dyad) which are open to own relationship, and comparison of30cases of2a kit ruled out a number of genes which are ruled out own relationship are carried out, in order to analyze the value of the two kits used in paternity test cases.In the60paternity test cases including the ones that don’t rule out own relationship, the RCP which is more than equal to99.999%of the two kits are47cases and42cases respectively, which occupy78.3%and70.0%(in paternity test including patents, RCP is more that equal to99.999%), while RCP which is more than equal to99.95%is4cases and7cases, which occupy6.7%and11.7%. Adopting t statistical method, in the comparison of patriarchal relative opportunity tested by the two kits, t is1.622and1.264, p is0.110and0.212,60cases does not exclude biological relationship of the two kits patriarchal relative opportunity for statistical analysis the Mann-Whitney U-value of1639, the P value of0.271, two kit does not exclude the paternity test results in no statisticallydifferences. It can be concluded that there is no significant difference in the results of patriarchal relative opportunity tested by the two kits. The test result of DNATyperTM15kit is obviously higher than that of IdentifierTM kit because of the participation of D6S1043and Penta E. In the30paternity test cases which is open to own relationship, among the236allelic genes which have been ruled out in the17STR loca bested by the two kits, the average number of genetic loci which is ruled out is6.9being checked out by DNATyperTM15kit excluding the3STR loca which is not conform to the genetic regularity, among which37loca are ruled out by both D6S1043and Penta E; on the other hand there is only one case that the2STR loca is not conform to the genetic regularity tested by IdentifilerTM kit. By the method of increasing the loca of DNATyperTM15kit to rule out own relationship,6.6loca are confirmed on average, among which29loca are ruled out by TH01、THOX and D19S433, including the number of8,7, and14. Adopting the method of McNemar, P=0.389(>0.05) and Kappa coefficient is0.73(>0.7), which means it is no statistically difference in result of rejecting different loca by the two kits, but it is same in rejecting ability. More exclude index and higher exclude rate are gotten because of the existing of D6S1043and Penta E loci and the other polymorphism loci in DNATyperTM15kit, while the limited role in ruling out because of the poorer polymorphism of frequency distribution in TH01, TPOX loci. Seeing from average total result of ruling out loci, the exclude ability of DNATyperTM15kit is higher than that of IdentifilerTM kit, although there is no statistical difference between the two kits. On the basis of the comparison of the above testing result, DNATyperTM15kit has the higher value for paternity identification of Chinese ethnic Han.According to the above research results, conclusion are as follows:1、In the inspection of polymorphism frequency distribution of Han people lived in Shenzhen, among each index of H, DP, PIC, PE, loci of D6S1043and Penta E chosen by DNATyperTM15kit is superior to that of TH01、THOX and D19S433chosen by IdentifilerTM kit. Therefore, locaidentified by DNATyperTM15kit is better in polymorphism frequency distribution of Han people lived in Shenzhen.2、DNATyperTM15and IdentifierTM kits are equal in testing ability in the testing of samples of routine inspection material, trace inspection materials, pollution inspection materials and degradation of material. Because the testing results are reliable and DNA typing is accurate, the result of passing sensitivity test is found, may succeed in and find the sample of template quantity above0.25ng.3TMIdentifilerTMkit has one more STR loci than DNATyperTM15kit, but because loci chosen by DNATyperTM15kit is better than IdentifilerTM15kit in polymorphism frequency distribution of Han people, and through comparison of the two kinds of kit used in the cases of not excluding the biological relations and ruling out the relationship, it is found that DNATyperTM15kit has higher application value in the cases of paternity identification in Han nationality in China.4、The domestic DNATyperTM15kit not only can be used for the construction of DNA databases apply to conventional and difficult cases test samples also. Ensure that the detection rate and accuracy of the sample, is more conducive to thecase test samples and the DNA database for comparison.What’s more, DNATyperTM15kit has chosen to test the genetic seats of many attitudes in the crowd of the Han nationality of Chinese, the individual suitable for the crowd of the Han nationality of Chinese discerns and paternity test of the right case. The box price of DNATyperTM15kit reagent is low, which can reduce and handle a case unit DNA and examine the cost greatly andthusrelieved the local government’s financial pressure.The construction of DNA laboratory at the basic level of our country has played facilitation. This kit also offer one DNA that accord with the China’s actual conditions, which is suitable for the Chinese crowd even more for national DNA laboratory and examine kit.