ABI Prism® 7900HT Sequence Detection System ... - OpenWetWare

5-6 End-Point Analysis
Genotypic Segregation of Datapoint Clusters
The figure on the previous page illustrates the concept of genotypic segregation of
samples within the allele plot. The plot contains four separate, distinct clusters which
represent the No Template Controls and the three possible genotypes (allele X
homozygous, allele Y homozygous, and heterozygous). Because of their
homogenous genetic compliment, homozygous samples exhibit increased
fluorescence along one axis of the plot (depending on the allele they contain). In
contrast, heterozygous samples appear within the center of the plot because they
contain copies of both alleles, and therefore exhibit increased fluorescence for both
reporter dyes.
About Outliers
Samples that did not cluster tightly may:
♦ Contain rare sequence variations
♦ Contain sequence duplications
♦ Not contain a crucial reagent for amplification (the result of a pipetting error)