The assay compares amplification of the suspected deleted region with amplification of a reference locus from the same genomic DNA sample. Fluorescence is monitored during PCR, and the resulting cycle threshold values show the relative amplification behavior of both loci. A reduced target signal relative to the reference supports loss of the defined DNA region rather than an unchanged genome.
The reference locus provides an internal comparison for the target sequence. Because both regions are assessed from the same genomic DNA preparation, their cycle threshold values can be evaluated together rather than relying on target amplification alone. This comparison helps identify reduced target copy number and makes the result more informative for distinguishing modified samples from unchanged ones.
A sample containing both modified and unchanged genomes may produce an intermediate target signal relative to the reference locus. Such a result can indicate that the deletion is present in only part of the tested population rather than uniformly across all cells. This makes the approach useful for screening cell lines or other samples before more detailed genotyping.
Researchers first obtain genomic DNA from the sample, then amplify the sequence targeted for deletion together with a reference locus. Fluorescence is measured as amplification proceeds, and cycle threshold values are compared between the two regions. The relative result is then used to classify samples as consistent with a deletion, unchanged, or potentially mixed, depending on the observed target copy number.
The method can be applied to genomic DNA from embryos, cell lines, or tissue samples. This range supports screening at different stages of developmental biology research, from identifying engineered changes in embryos to checking established cell populations or collected tissues. In each case, the analysis focuses on whether the defined target region remains present relative to the reference locus.
qPCR deletion screening is useful when researchers need a rapid and sensitive way to screen many candidate samples for a defined deletion. It can identify samples that warrant further characterization, while sequencing or other genotyping methods can provide complementary information about the genetic change. In developmental studies, this combination helps connect engineered deletions with embryo, cell, or tissue analyses.