Nine plasmids carrying 129 (filled) and FVB (open) Afp cDNA inserts were assayed. The structure of each plasmid is depicted in cartoon form, and the expected fractional value of the FVB allele, γFVB(Ex), is indicated. After restriction enzyme digestion and PCR amplification, melting analysis was performed using FRET probes Afp-F and Afp-R. Using three reference standards, pure FVB cDNA, pure 129 cDNA, and plasmid pTG1 (a 1:1 mass mixture of FVB and 129 DNAs), the corrected fractional values for FVB DNA, γFVB_C, were calculated. (SD) Standard deviation (N = 3); (N/A) not applicable.