Abstract: Objective To investigate DNA degradation of porcine retinal cells by single cell gel electrophoresis（SCGE） for estimation of postmortem interval（PMI）. Methods Degradation of retinal cells was observed by SCGE at 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22 and 24 h after death respectively, under the environmental conditions of being kept in dark place as well as a controlled temperature of （15±2） ℃ and humidity of （50±5）%. The comet pictures were captured by fluorescence microscope and analyzed by single cell gel electrophoresis（IMI 1.0）. Results From 2 h to 24 h postmortem, the degree of degradation of retinal DNA increased with the prolongation of PMI. The postmortem regression functions of head DNA%, LT/LH, IT/IH were y=92.227-5.188 x+0.019 x2+0.001 x3（R2=0.971）, y=0.035e0.191 x（R2=0.947）, y=0.099e0.264 x（R2=0.955）, respectively. Conclusion The examination of retinal cell DNA degradation by SCGE is useful for estimating PMI.

Key words: forensic genetics, retina, comet assay, swine, DNA degradation, postmortem interval