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Background and purpose of STR is widely present in the human genome, a class of highly polymorphic short tandem repeats, also known as microsatellite DNA. As the second generation of genetic markers, STR has been widely used in individual identification, paternity testing, fine genetic map construction, linkage disequilibrium analysis, loss of heterozygosity of the tumor suppressor gene, disease gene mapping and organ transplantation fields. STR polymorphisms in population genetics studies form the basis of forensic applications, STR analysis has greatly expanded the scope of forensic evidence examination. Tumor suppressor gene is usually inactivated by the two-hit mechanism, that one allele of the mutation, and the other allele loss of heterozygosity. Loss of heterozygosity is a common genetic changes found in the genome of the most solid tumors. Non-random regional loss of heterozygosity may mean that in this area there tumor suppressor gene, its absence can promote tumor development and progression, so it may have cancer, the significance of the development of prognostic sign. The purpose of this project is to find new STR loci in the chromosome 6q24-25.1 region, to provide a wider choice of STR genetic markers for various applications in the field of forensic medicine and oncology; investigation 6q24-25.1 region on the new STR loci Block in Henan Han population genetic polymorphism, evaluate its use in forensic science. We 6q24-25.1 region on the four new search STR markers to detect LOH in 30 cases of gastric cancer specimens, in order to further elucidate the molecular mechanisms of gastric cancer. The method of looking for new STR loci in the region of the human chromosome 6q24-25.1, and select the repeating units for the four nucleotide microsatellite primers were designed using Primer3 software; application cooling PCR amplified loci, Electrophoresis. Optimize their amplification conditions, to find the different alleles within groups, build allelic ladder matter. Investigation STR loci on chromosome 6 newly discovered in Henan Han population allele frequencies. The PowerStats vl.2 software analysis results, population genetics data to calculate the probability of individual identification (PD), paternity exclusion (PE), polymorphic information content (PIC), allele frequencies (frequency), heterozygosity ( H) and other forensic parameters. Select the 6q24-25.1 region on four STR markers, polymerase chain reaction, non-denaturing polyacrylamide gel electrophoresis (PCR) to detect LOH occurrence of tumor tissue and normal control tissue. Results Find DNA sequence on chromosome 6, we found 14 new STR loci, six loci PD value, H and PIC taller and easy and accurate typing, respectively named: D6SZ2 D6SZ6 a D6SZ7, D6SZ8, D6SZ9, D6SZ12, the amplified fragment of 219bp, 150bp, 167bp, 234bp, 246bp, 193bp (reference sequence). 6 STR loci were of 6,6,7,4,7,5 detected alleles in Henan Han population H values ??were 0.555,0.555,0.585,0.712,0.667,0.750, PD values The 0.857,0.811,0.821,0.803,0.829,0.827 PIC are 0.65,0.57,0.62,0.60,0.61,0.64. 4 STR genetic markers found LOH results on 30 patients with paired gastric cancer and normal control tissue, 30 cases of gastric cancer samples, 3 samples of LOH at 6q24.2 D6SZ7 LOH at the highest frequency, reaching 15.0%, followed by the 6q24.1 D6SZ2 (11.1%), the 6q24.2 D6SZ8 (9.09%), 6q24.2 D6SZ9 (6.25%) Conclusion on DNA sequence information in the 6q24-25.1 region, we find 6 polymorphic good, easy-to-accurate genotyping STR loci can be used in forensic examination of human genetics research. In this area is a candidate tumor suppressor gene PLAGL1 and low frequency of LOH in gastric cancer specimens.
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