Polymerase chain reaction (PCR)-based genotyping of representative progeny of a cross between γ3 +/- mice. A. Schematic of PCR primers used for genotyping: primers for wild-type γ3 allele, blue arrows; primers for defective γ3 allele, red arrows. B. Results for mice representing all three γ3 genotypes (w: +/+; k: -/-; h: +/-). The band produced by the primers for the wild-type (+) γ3 allele is 750 base pairs (bp), and the band produced by the primers for the disrupted (knockout or -) γ3 allele is 628 bp. m -size markers.