Y chromosome short tandem repeat analysis of semen stains exposed different environment conditions depending time interval

Purpose: In cases of sexual assault, it is possible to achieve the identity of perpetrators by examining semen stains detected on the victim?s garments or environment. In daily routine, Y chromosome short tandem repeat analysis is successfully used in sexual assault cases, to identify male perpetrator from biological materials of female-male mixture in crime scene and in cases of paternity. Semen stains detected at crime scenes are generally expose to poor environmental conditions with a long time interval. Since these stains contain degraded DNA samples in a small amount of material, DNA profiling should be performed at one analysis. In this study, the determination of Y chromosome short tandem repeats of semen stains exposed different environment conditions will be investigated.Materials and Methods: In this study, samples prepared from semen of five volunteer individuals were used. Semen samples spotted on gauze were dried at room temperature. Following this step, three different environments, incubator (37 °C) refrigerator (4 °C) room temperature (25 °C), were prepared for dried samples for six months. DNA extraction was performed from each sample. Obtained DNA underwent polymerase chain reaction amplification and capillary electrophoresis. As the last step, DNA quantitation performed for samples at the third and sixth month of storage.Results: Y chromosome short tandem repeat profile was obtained from all of the stains kept for six months. DNA quantitation revealed that the level of DNA degradation were higher in the samples of sixth month compared to third month. DNA degradation level was the lowest in the samples kept in the refrigerator, which followed by room environment and oven.Conclusion: It is concluded that, Y chromosome short tandem repeat profiling can be carried out in semen stains stored in different environment conditions for six months. In concordance with literature findings, it was found that DNA degradation increases depending on the time and temperature has negative effects on degradation.