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Objective To evaluate the effects of DNA examination of trace bloodstain samples from the scene collected with Trace Biological Evidence Collection kit. Methods Venous blood was made into bloodstains on the ground. The trace bloodstain samples were collected with Trace Biological Evidence Collection kit and common methods, respectively. DNA examination of trace bloodstain samples （50 from each group） was conducted on the constant temperature shaker for 2, 24, 48, 72, and 96 h, respectively, and the examination results of every group were compared. Results When the trace bloodstain samples were placed on the constant temperature shaker for 24, 48, 72, and 96 h, the DNA detection rates in the group which used Trace Biological Evidence Collection kit （100.00%, 100.00%, 100.00%, 96.00%） were significantly higher than those in the group using common methods （62.00%, 26.00%, 10.00%, 0）, the differences had statistical significance （P<0.05）. When the trace bloodstain samples were placed on the constant temperature shaker for 2 h, the differences of DNA detection rates between the two groups had no statistical significance （ P>0.05）. Conclusion The Trace Biological Evidence Collection kit can effectively improve DNA detection rate and extend detection time limit for trace bloodstain samples from the scene that have been stored for a relatively long time.
Subject(s)
Blood Stains , DNA , Forensic Medicine , TemperatureABSTRACT
Objective To explore the effect of benzidine test and related reagents on DNA analysis of bloodstain. Methods A total of 970 bloodstain filter paper samples with 1μL venous blood were collected, and 10 of them acted as control samples. After benzidine test and related reagent processing, DNA of 960 samples was extracted by Chelex-100 and silica bead methods and then multiplex amplified by AmpF(e)STRTM IdentifilerTM Plus PCR kits. The results of STR typing were compared between different groups. Results DNA were extracted immediately after benzidine test. Totally STR loci (3.80±1.34) were detected by silica bead method, while no STR loci were obtained by Chelex-100 method. Thirteen sam-ples (21.7％) with whole STR typing results were obtained by drying after benzidine test, and the STR locus number (12.90±1.49) which obtained by silica bead method was much higher than by Chelex-100 method (4.70±1.96) (P<0.05). When DNA was extracted immediately after the addition of glacial acetic acid, the STR locus number was (9.40±2.09) by silica bead method, but no STR typing result was obtained by Chelex-100 method. All 15 STR loci could be obtained by only adding glacial acetic acid after drying and only adding tetramethylbenzidine alcoholization liquid or 3％ hydrogen peroxide liquid. Conclusion Benzidine test has significant influence on DNA analysis of bloodstain. The Chelex-100 method is not suitable for the DNA extraction of bloodstain after benzidine test. Drying after benzidine test and silica bead methods can effectively enhance the STR locus number of bloodstain.
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Objective To investigate the polymorphisms of 23 Y-STR loci in a Han population in Jiangsu province. Methods Blood samples were collected from 4821 unrelated healthy Han males in Jiangsu province. DNA templates were amplified by PowerPlex Y23 kit,and the amplification products were detected by 3500xL genetic analyzer. Then,we calculated the allele frequencies and gene diversities respectively,as well as the haplotype frequencies and haplotype diversities. Results The gene diversity of these 23 Y-STR loci ranged 0.4099-0.9696. A total of 4781 haplotypes were detected,of which 4743 were found once. The haplotype diversity was 0.99999812. Conclusion The 23 Y-STR loci used in this study are highly polymorphic in Han individuals in Jiangsu province and therefore suitable for population genetic study and forensic individual identification.
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<p><b>OBJECTIVE</b>To investigate the polymorphism of 17 short tandem repeat (STR) loci of Tibetan minority ethnic group from Lhasa.</p><p><b>METHODS</b>Blood samples were obtained from 132 unrelated Tibetan individuals from Lhasa. DNA templates were screened by home-made AGCU17+1 kit and 3130XL genetic analyzer. Genotyping was performed using GeneMapper software (version 3.2).</p><p><b>RESULTS</b>The allele frequencies of 17 STR loci ranged 0.0038-0.5720, and the power of discrimination ranged 0.779-0.979, the power of exclusion ranged 0.327-0.737, the polymorphism information contents ranged 0.538-0.910, and the heterozygosity ranged 0.629-0.871. The cumulative coupling probability was 3.93 × 10(-20), and the cumulative power of exclusion was 0.9999995234. Of 17 STR loci, Penta E and D6S1043 had the highest polymorphism indicators, while TPOX had the lowest.</p><p><b>CONCLUSION</b>The 17 STR loci used in this study are highly polymorphism in Tibetan minority ethnic group from Lhasa and fit for the population genetic study and forensic cases.</p>
Subject(s)
Humans , Asian People , Genetics , Ethnicity , Genetics , Gene Frequency , Genotype , Microsatellite Repeats , Genetics , Minority Groups , Polymorphism, Genetic , TibetABSTRACT
OBJECTIVE@#To improve DNA extraction from bloodstain on the filter paper and to establish a rapid, simple, and cost-effective method for DNA extraction suitable for database construction.@*METHODS@#Seven hundred and fifty two aged bloodstains on filter paper were randomly divided into four groups. The four different DNA extraction methods were compared with each other, and two DNA extraction methods used for 63 fresh bloodstains on filter paper were also compared with each other.@*RESULTS@#There were no statistically significant differences observed among the four DNA extraction methods (P > 0.05) for aged bloodstains on filter paper; But the difference between the two DNA extraction methods for fresh bloodstains on filter paper was obviously (P < 0.05).@*CONCLUSION@#Extraction of DNA samples from aged bloodstains on filter paper can be accomplished by using Chlex-100 methodology directly with no need to wash the bloodstains.
Subject(s)
Humans , Blood Stains , Chelating Agents , DNA/isolation & purification , Endopeptidase K , Forensic Medicine/methods , Indicators and Reagents/chemistry , Polymerase Chain Reaction , Resins, Synthetic , Specimen Handling/methods , WaterABSTRACT
Objective To monitor state of environment control and life support system (ECLSS), and to diagnose faults and provide decision support in manned space flight. Methods According to the principle of decision support system, neural networks and the expert system, the foundational constructional structure and work flow of the ECLSS decision support system(EDSS) were designed,fault tree analyze(FTA) method was used to sort all of the faults and to form the expert knowledge framework, expert system and neural networks were integrated to adaptive learning from experience. Results In the two-men-five-days SZ-6 manned space flight, this software system worked well, and had reduced the difficulty and intensity of ground flight control and had provided good technological support for the consummation of this flight. Conclusion For the first time, the ECLSS decision support system is designed and implemented by using database and expert system technology. It can judge parameters state and diagnose faults exactly and rapidly, and the data models are designed correctly to give the rational result of parameter prediction.