Sex Genotyping by Flow Cytometry.

A flow cytometry assay for sex genotyping at single cell resolution is described. This assay is based on the detection of a Y chromosome-specific gene by in situ PCR. The protocol requires the isolation of lymphocytes from human blood, their fixation, permeabilization, and mild protein digestion, and the amplification of a Y chromosome-specific gene SRY, which is present only in male cells, by in situ PCR with a universal energy transfer-labelled primer (UniPrimer). Male cells can be detected by flow cytometry because the SRY gene is amplified and fluorescently labelled solely in male cells.