Development of Dermestes Maculatus at a Constant Temperature and Its Larval Instar Determination / 法医学杂志

Objective To establish the basic data for estimating minimum postmortem interval （PMImin） of heavily decayed and skeletonized remains by studying the development of Dermestes maculatus DeGeer （Coleoptera: Dermestidae）. Methods The developmental stages of Dermestes maculatus were observed at four constant temperatures of 20 ℃, 24 ℃, 28 ℃ and 32 ℃, and the changes in body length were also examined as the biological indicator to estimate larval day-age and instar. Results The total developmental time from egg to adult at 20 ℃, 24 ℃, 28 ℃ and 32 ℃ were （126.7±10.6） d, （69.4±8.2） d, （50.4±8.4） d and （49.6±6.5） d, respectively. The body length increased gradually, but changed irregularly as a whole. Conclusion The study provides basic data on the development and growth of Dermestes maculatus, especially on its developmental duration as a significant value for estimating PMImin of heavily decayed and skeletonized remains. Nevertheless, the change of body length is not found to be the best biological indicator for instar determination.

Research Progress on InDel Genetic Marker in Forensic Science / 法医学杂志

Genetic markers in forensic DNA typing experienced the variable number of tandem repeats （VNTR） sequences and the short tandem repeats （STR） sequences. With the emerge of sequencing technology, the third generation of genetic markers were found out, which usually have two alleles including single nucleotide polymorphism （SNP） and insertion/deletion （InDel）, also known as biallelic genetic markers. Because of the insertions or deletions of DNA fragments, InDel genetic marker reveals DNA fragment length polymorphism and widely distributes across the whole genome. InDel genetic marker is numerous and has the characteristics of STR and SNP genetic markers, which has been applied in the fields of genetics and anthropology. This review focuses on the research progress of InDel genetic marker in forensic science, aiming to review and summarize the main research findings in recent years and provide clues for future researches.

Assessment on Application of 24 Y-STR Loci in Forensic Science / 法医学杂志

OBJECTIVES@#To select a Y-STR marker system with strong haplotype identification ability, appropriate mutation rate and high compatibility and to assess its forensic application.@*METHODS@#The 24 Y-STR loci were tested by self-built fluorescent multiplex system, and the forensic assessment was conducted by 139 pairs of father-son samples collected in Jinan, Shandong province.@*RESULTS@#Totally 176 alleles were identified among the 24 Y-STR loci in the sample of 139 unrelated individuals labeled with father, and the gene diversity （GD） distributed between 0.083 7 （DYS645）-0.966 9 （DYS385a/b）. According to the 24 Y-STR loci, 139 different haplotypes were detected from 139 unrelated male individuals labeled with father in Han population of Shandong province and with no shared haplotype observed. The overall haplotype diversity （HD） was 1 and the discrimination capacity （DC） was 1. A total of 5 one-step mutations events were observed among the 24 Y-STR loci in 139 pairs of father-son. The average mutation rate was 0.001 5 [95% CI （0.000 5, 0.003 5）].@*CONCLUSIONS@#The system of 24 Y-STR loci shows a strong individual recognition ability and low mutation rate in the population in Jinan, Shandong province, and it has good application value in forensic science.

Establishment of 43-plex SNP Typing System and Its Forensic Application / 法医学杂志

Objective To evaluate the application of 43-plex SNP typing system in forensic science. Methods The typing of 43 SNP loci in 123 unrelated Han individuals from East China was detected by MALDI-TOF-MS. The application value of 43-plex SNP typing system was assessed according to the foren-sic parameters of population genetics. Results All the 43 SNP loci of 123 individuals showed no signifi-cant departure from Hardy-Weinberg equilibrium (P>0.05). Excepted rs1355366, rs2270529, rs10776839 and rs938283, there were 39 SNP loci had minor allele frequencies (MAF), which were greater than 0.25. Among the 25 loci MAFs, 24 ranged from 0.4 to 0.5, while 3 were close to 0.4. The DP, CDP, PIC, Ho, PEtrio and PEduo of the 43 SNP loci were 0.2901-0.6544, 1-9.8×10-11, 0.1708-0.5000, 0.1557-0.5935, 0.0854-0.2500 and 0.0146-0.1250, respectively. The CPEtrio and CPEduo were 0.999986 and 0.9924361, respectively. Conclusion The 43-plex SNP typing system in present study shows a high polymorphism, which can be an effective supplement and verification for traditional STR genetic markers. It also can be used with other commercial kits for the forensic paternity testing and individual identification.

Forensic Application of SiFaSTRTM 23plex DNA ID System in Han Population of Eastern China / 法医学杂志

Objective To investigate the genetic polymorphism of 21 autosomal STR loci and DY S391 locus of SiFaSTRTM 23plex DNA ID system in Han population of eastern China and to evaluate its ap-plication value in forensic science. Methods Typing test of 2000 unrelated individuals was performed using SiFaSTRTM 23plex DNA ID system. The population genetic parameters of STR loci were statistically analysed. A total of 3198 parentage confirmed cases were detected with that system and the mutation conditions were observed in 21 autosomal STR loci. Results All the 21 autosomal STR loci showed no significant departure from Hardy-Weinberg equilibrium (P>0.05). The Ho ranged from 0.6175 to 0.9270. The DP ranged from 0.7964 to 0.9869, as well as the PIC distributed from 0.5611 to 0.9123. The CDP was 0.999999999999999. The CPEduo was 0.999997431701961, while CPEtrio was 0.999999999654865. Five alleles were detected in DY S391 locus, with the allele frequency from 0.0040 to 0.7290, and GD was 0.4189. Except D13S317 and D10S1248, seventy-six mutation events were observed at the rest nineteen autosomal STR loci. Among them, seventy-five (98.68％) were one step mutation, and only one (1.32％) was three steps mutation. The mutation rate ranged from 0.2465×10-3 to 2.7114×10-3, and the averaged mutation rate was 0.8921×10-3 (95％ CI: 0.70×10-3-1.10×10-3). In 33 trio mutation cases, the proportion of the paternal mutation and the maternal mutation was 2.09:1. Conclusion The involved STRs are highly polymorphic in Eastern Han population with acceptable mutation rates by the SiFaSTRTM 23plex DNA ID system, which is suitable for paternity testing and individual identification.