Abstract: Objective To establish more sensitive methods for detection of DYS385 in routine forensic casework. Methods The primers recommended by Genome Database (GDB) and Schneider were used to amplify DYS385 respectively. Then, a semi-nested PCR of DYS385 was designed by using the two different primers as outer and inner primer. A series of experiments were carried out to achieve good result by adjusting the ratio of outer/inner primer and optimizing the PCR condition. Results It showed that an overall 112bp shorter DYS385 fragments and better electrophoretic separation were obtained by using primer2B. By using the semi-nested PCR approach, the shorter specific DYS385 fragments could be amplified and detectable DNA amounted to 50pg. Conclusion This method is 20 fold more sensitive than the ordinary method.

Key words: DYS385, semi-nested PCR, Y chromosome