Methods of capturing sperm nucleic acids

A method of detecting sperm deoxyribonucleic acid (DNA) in a biological sample, comprising:

• providing the biological sample comprising at least a sperm cell, a partially lysed sperm cell or a sperm cell lysate, wherein the sperm cell, partially lysed sperm cell or sperm cell lysate comprises a protamine-DNA complex;
• contacting a lysis solution to the biological sample to lyse the sperm cell or partially lysed sperm cell, wherein the lysis solution comprises at least one of a reducing agent and a detergent, wherein the protamine-DNA complex remains intact after contacting the lysis solution;
• applying a sequestration agent after the sperm cell lysis to the sample comprising the lysed sperm cells, or the partially lysed sperm cells and an excess of the lysis solution to sequester an excess detergent of the excess of the lysis solution;
• applying at least a protamine-specific antibody to the lysed sperm cell after the sequestration of the excess detergent, wherein the protamine-specific antibody binds to the protamine-DNA complex of the lysed sperm cell to form an antibody-protamine-DNA complex;
• capturing the antibody-protamine-DNA complex by adding a capturing agent;
• and
• detecting the sperm DNA from the captured antibody-protamine-DNA complex by a DNA amplification reaction.