Constructing standard allelic ladders for four short tandem repeat loci and employing them in a population study on Han Nationality of Chengdu in China / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To solve the problems in the accuracy and standardization of short tandem repeats-polymerase chain reaction (STR-PCR) typing, the authors adopted the molecular clone technology in producing the standard allelic ladders of D1S1676, D2S2735, D11S1977 and D22S444 loci and applied them in a population study on the Hans in Chengdu, China.</p><p><b>METHODS</b>PCR was used to produce several different allelic fragments of these loci. PCR products were eluted from the gel and re-amplified by PCR. The purified allelic fragments were then blunt-end subcloned individually into the pGEMR-T plasmid vectors and the recombinant were transfected into competent E.coli DH5alpha TM cells. The results of sequencing confirmed that the size and the construction of the inserts were correct. The recombinant plasmids DNA with the inserts were then used as template for re-amplification to generate the four loci standard ladders.</p><p><b>RESULTS</b>The authors succeeded in producing large quantity of standard allelic ladder of these four loci, with which the genetic polymorphisms of these loci in Chengdu Han population of China were studied.</p><p><b>CONCLUSION</b>This method is of high value for forensic DNA typing to construct standard ladders. D1S1676, D2S2735 loci are robust for forensic analysis in Chinese Han population, whereas the value of D11S1977 and D22S444 loci is limited.</p>

DNA samples preparation from single cell and its application in sensitivity test / 法医学杂志

OBJECTIVE@#To establish a reliable, exact and practical method to prepare DNA samples for sensitivity-test purposes.@*METHODS@#The micromanipulation method was employed to prepare exact quantity DNA samples used to study the sensitivity of Profiler Plus Kit-ABI PRISM 310 system.@*RESULTS@#We succeed in establishing a micromanipulation method to prepare groups of DNA samples, which contain 1-11 cells in turn, and also succeed in using them to study the sensitivity of Profiler Plus Kit-ABI310 system.@*CONCLUSION@#The method we have established is proved to be a reliable, exact and practical way to prepare DNA samples for sensitivity-test purposes.