ABSTRACT
Objective The purpose of this study was to investigate the feasibility of short tandem repeat(STR) genotyping of cell free DNA in plasma for individual identification and paternity testing. Methods EDTA-Na2 DNA anti-coagulant blood samples were collected from 36 unrelated healthy volunteers,and both DNA in leukocytes and cell free DNA in plasma were extracted respectively using phenol-chloroform method. Target DNA in blood cells and plasma were amplified using regular STR typing and fluorescent multiplex STR assay separately,accordingly,the PCR products were analyzed by polyacrylamide gel electrophoresis and capillary electrophoresis. Results Using either normal PCR-STR or fluorescent multiplex STR assay,the consistent STR genotyping results were detected with similar efficiency for cell DNA and plasma DNA samples from the same individual. Conclusion Cell free DNA in plasma samples can be used as useful biological samples for STR genotyping,which can be applied to individual identification and paternity testing in forensic practice.