Digoxigenin labelling and laser capture microdissection of male cells.

Laser capture microdissection (LMD) is a relatively new technique for the isolation of single cells. The application in forensic investigations has become more and more widespread, especially to select spermatozoa out of mixtures with vaginal cells. In particular in cases with low numbers of sperm it could be profitable to isolate all male cells (e.g. sperm and male epithelial cells) instead of focussing on the sperm only. Therefore, the specific labelling and detection of the male cells in a male/female cell mixture is necessary. In order to label all cells carrying a Y-chromosome we used a digoxigenin labelled chromosome Y hybridisation probe (Q Biogen). The stained cells were isolated with the SL microCut LMD system from Molecular Machines & Industries AG (MMI). At least ten diploid male cells were required to obtain a partial STR profile, with 20 cells, a full profile could be obtained.