Figure 5. The nob ERG phenotype does not segregate with the tg21 transgene. A: Pedigree of a two-generation cross between tg21 no-b-wave and DBA/2N mice. All F1 offspring had normal electroretinograms (ERGs). A: Of 98 F2 progeny, 19 mice had a no-b-wave (nob) ERG phenotype; of these, four were non-transgenic (DBA). B: Genotyping demonstrated that tg21 and the nob ERG phenotype do not cosegregate. Note that mouse #3 is non-transgenic and has a nob ERG.