An allelic discrimination plot, also known as a "cluster plot" or an "AD plot" is shown below. Ideally, these plots show three clusters, and near the origin, the No Template Control (NTC). These clusters are described in the table below. The points in each cluster are grouped closely together, and each cluster is well separated from the other clusters.  

A Typical three-cluster allelic discrimination plot

 

Assignment of clusters in an allelic discrimination plot


Samples Containing... Are grouped in...
Allele X (homozygote), labeled with VIC® dyeLower right corner of the plot
Allele Y (homozygote), labeled with FAM™ dyeUpper left corner of the plot
Both (allele X and allele Y—heterozygote)Approximately midway between the allele X and allele Y clusters
No template control (NTC)Bottom left corner of the plot
UndeterminedAnywhere on the plot