Streamlined and quantitative detection of chimerism in mouse tissue using digital PCR

Animal chimeras are widely used for biomedical discoveries, from developmental biology to cancer research. However, the accurate quantitation of mixed cell types in chimeric and mosaic tissues has challenges. Here, we have developed and characterized a droplet digital PCR single-nucleotide discrimination assay to detect chimerism among albino and non-albino mouse strains. In addition, we have validated that this assay is compatible with crude lysate from most organs, drastically streamlining sample preparation. This chimerism detection assay has many additional advantages over existing methods including its robust nature, minimal technical bias, and ability to report the total number of cells in a prepared sample. Importantly, the concepts developed and discussed here are readily adapted to other genomic loci to accurately measure mixed cell populations in any tissue.