Application of Chlorophyte ChlB Gene and Cyanophyte NIES Gene in the Detection of Drowning-Related Plankton / 法医学杂志

Objective To construct a polymerase chain reaction-capillary electrophoresis （PCR-CE） detection method using ChlB gene and NIES gene, investigate the method's specificity and sensitivity, and to evaluate its application value in drowning diagnosis. Methods The specific primers ChlB and NIES were designed for the conserved sequence of chlorophyte ChlB gene and cyanophyte NIES gene in GenBank to construct PCR-CE detection method; 50 species of standard DNA samples were amplified; the sensitivity was determined by gradient concentration detection of positive standard samples; 25 actual cadaver lung tissue samples （drowned： 20, natural death： 5） were detected, and the simultaneous detection results of microwave digestion-vacuum filtration-automated scanning electron microscopy （MD-VF-Auto SEM） were simultaneously compared. Results The minimum DNA detection concentration of primers ChlB and NIES was 0.161 ng and 0.109 ng, respectively, which could specifically amplify chlorophyte （Chlorella pyrenoidosa） and cyanophyte ［Microcystis aeruginosa （producing and not producing toxin）］ widespread in water. The product fragments were 156 bp and 182 bp, respectively. The results of non-drowning tissues were negative. Conclusion This method has high sensitivity and specificity. It can be applied to the detection of plankton related to drowning and combined with MD-VF-Auto SEM method, can increase the detection range of plankton related to drowning and improve the evidence power of drowning diagnosis.

Polymorphisms of 11 Y-chromosomal short tandem repeat loci in Chongqing Tujia ethnic group and genetic relationships with 16 populations / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the genetic polymorphisms of 11 Y-chromosomal short tandem repeats (STR) loci in Chongqing Tujia population, and to evaluate their forensic application values and genetic relationships with the other 16 populations of China.</p><p><b>METHODS</b>Eleven Y-STR loci in 215 unrelated Tujia individuals from Chongqing were amplified with PowerPlex Y System, and the PCR products were analyzed by 310 Genetic Analyzer. Cluster analysis and phylogenic trees were applied to show the genetic distance among the populations.</p><p><b>RESULTS</b>A total of 195 haplotypes were identified and the overall haplotypes diversity for the 11 Y-STR loci was 0.9942. The gene diversity values (GD) for each locus ranged from 0.3757 (DYS391) to 0.9170 (DYS385a/b). Comparing with other 16 populations, the genetic distance between Tujia and Tibetan was the nearest (0.02467), that between the Tujia and Korean ethnic groups was the farthest (0.25350).</p><p><b>CONCLUSION</b>The genetic distribution of the 11 Y-STR loci in Chongqing Tujia population showed favorable polymorphisms. They are suitable for forensic identification and paternity testing in the local area. The study of genetic diversity among different populations is useful in understanding their origins, migrations and their relationships.</p>

Heteroplasmy in human mtDNA control region / 法医学杂志

OBJECTIVE@#To observe the length heteroplasmy and point heteroplasmy in human mtDNA control region.@*METHODS@#The peripheral blood, buccal cell, and single hair shaft from 50 individuals and 16 family members, related in their maternallineage were analyzed by direct sequencing, and clones from 20 individuals whose mtDNA sequences have a T-C transition at 16189 nt were sequenced.@*RESULTS@#No point heteroplasmy were observed in peripheral blood, buccal cell, single hair shaft from the same individual, neither in maternally related individuals. Length heteroplasmy was observed in those individuals with a homopolymeric tract and the different clones from the same individual has different proportions of length variants, but the hair shafts from the same individual were very similar to the measurements made from blood DNA. No length heteroplasmy was observed between different tissues from the same individual.@*CONCLUSION@#mtDNA sequences have a characteristic of high consistency and genetic stability, mtDNA sequencing is a suitable tool for forensic applications such as individual identification.