Abstract: A method for selectively recovering nucleic acid from a first cell type in a sample containing cells of at least a first cell type and a second cell type, and a cell suspension medium comprising extracellular impurities, is provided. The method entails combining the sample with particles responsive to a magnetic field in a vessel, the magnetic particles having the ability to sequester the cells from the cell suspension medium upon application of a magnetic field; exposing the vessel to a magnetic field for a time sufficient to cause sequestration of the cells by the particles; removing the impurities-containing cell suspension medium from the vessel while retaining the cells; lysing selectively cells of the first cell type; and isolating the nucleic acid from the lysed cells. Methods for recovering nucleic acid from the second cell type are also provided.

Abstract: The invention relates to a method for simultaneous quantification of human nuclear DNA and human male DNA in a biological sample while also detecting the presence of PCR inhibitors in a single reaction. The multiplex quantification method also provides a ratio of human nuclear and male DNA present in a biological sample. Such sample characterization is useful for achieving efficient and accurate results in downstream molecular techniques such as genotyping.