Microdeletion and Mutation of Y Chromosome in Full Sibling Identification / 法医学杂志

OBJECTIVES@#To explore the identification method of full sibling between two males with microdeletion and mutation of Y chromosome.@*METHODS@#DNA were extracted from two samples. The type testing of Y-STR and autosomal STR were performed. Full sibling between two individuals was calculated by IBS, ITO and discriminant functions methods.@*RESULTS@#There were 2 loci mutations existed in 33 Y-STR loci and one of the two samples had 19 loci deletions. The IBS of two samples was 53 and greater than the threshold which was 42; FSI was 1.36×10¹⁶ and far greater than 19. The discriminant function of full sibling-unrelated individual DFS2 was greater than DR2, which meant the two individuals tend to be full sibling.@*CONCLUSIONS@#The methods of IBS, ITO and discriminant functions of full sibling-unrelated individual can be used comprehensively to provide more reliable expert opinion in microdeletion and mutation of Y chromosome in full sibling identification.

Analysis and Discussion on Calculating Likelihood Ratio of DNA Mixture / 法医学杂志

OBJECTIVE@#To analyze and discuss four methods of calculating likelihood ratio of DNA mixture.@*METHODS@#In the case with CNAS-T0757 proficiency testing in 2013, the likelihood ratios were calculated and compared among four methods, including unrestricted combinatorial method, Clayton's method, p2 principle method, and recommendations from ISFG.@*RESULTS@#The likelihood ratios were maximum by Clayton's method and recommendations from ISFO, followed by result of the unrestricted combinational method. The minimum likelihood ratio was obtained by p2 principle.@*CONCLUSION@#The unrestricted combinational method could give fUrthest consideration to both information preservation and appraiser protection.

Genetic polymorphisms of 16 non-CODIS STR loci in Beijing Han population / 法医学杂志

OBJECTIVE@#To investigate the genetic polymorphisms of 16 non-CODIS loci (D6S477, D22-GATA198B05, D15S659, D8S1132, D3S3045, D17S1290, D14S608, D2S441, D18S535, D13S325, D10S1435, DlS2368, DIS1656, D7S3048, D10S1248 and D19S253) in Beijing Han population.@*METHODS@#The DNA of 300 unrelated individuals in Beijing Han population were PCR amplified using GoldeneyeM DNA identification system 18NC kit, and the PCR products were analyzed by electrophoresis through 3130XL genetic analyzer. The fragment sizes of alleles were taken subsequently by GeneMapper v3.2.@*RESULTS@#The distributions of genotype frequencies of 16 non-CODIS STR loci in Beijing Han population satisfied the Hardy-Weinberg equilibration. The population genetic parameters were obtained as followings: heterozygosity was 0.677-0.873; discrimination power, 0.890-0.967; probability of paternity exclusion, 0.393-0.741; and polymorphism information content, 0.706-0.853.@*CONCLUSION@#These 16 non-CODIS STR loci show great genetic polymorphisms in Beijing Han population, and are useful for the research of population genetics and forensic application.

A new method of identifying the peripheral blood and the menstrual blood / 法医学杂志

OBJECTIVE@#To explore the tissue-specific gene expressions of the peripheral blood and the menstrual blood, and to search some specific factors to establish an effective method for identifying the peripheral blood and the menstrual blood.@*METHODS@#The specific products of the peripheral blood and the menstrual blood were detected by RT-PCR and separated by electrophoretic technology.@*RESULTS@#Beta-spectrin (SPTB) as one specific marker of peripheral blood and 18S rRNA as a kind of the housekeeping gene were expressed in both the peripheral blood and the menstrual blood. However, matrix metalloproteinase 7 (MMP7) as one specific marker of menstrual blood and human beta defensin 1 (HBD1) as one specific marker of vaginal discharge were only found in the menstrual blood.@*CONCLUSION@#There are differences of specific gene expressions between the peripheral blood and the menstrual blood. They could be accurately distinguished from each other by using the combination of fluorescence technology and RT-PCR to detect the specific identification of mRNA.

Application and progress of RNA in forensic science / 法医学杂志

With the development of molecular biology, the evidences of genetics has been used widely in forensic sciences. DNA technology has played an important role in individual identification and paternity testing, RNA technology is showing more and more wide application in prospect. This article reviews the application and progress of RNA in forensic science including estimation of postmortem interval, bloodstain age, wound age, as well as determination of cause of death and the source of body fluids.

Polymorphisms analysis of mitochondrial DNA in coding area / 法医学杂志

OBJECTIVE@#To analyze mitochondrial DNA (mtDNA) polymorphisms in coding area and provide a theoretical basis for applying in forensic science.@*METHODS@#The primers of 8162F/8483R and 13070F/13299R were designed according to the Anderson's sequence. Using PCR-sequencing method to detect polymorphisms of mtDNA nt8162-8483 and nt13070-13299.@*RESULTS@#The lengths of the amplicons were 322 bp and 230 bp respectively. There were 24 mitochondrial haplotypes defined by 21 variable positions in both regions. The gene diversity was estimated at 0.751 1, and the probability of two randomly selected individuals having identical mtDNA types was 0.256 4.@*CONCLUSION@#The polymorphic sites within mtDNA coding area can be useful in combination with mtDNA control region in order to increase the discrimination power.