S1 nuclease protection assay of human Aγ transgene expression in HS3ɛγ and HS3ɛγ^−1086Mut lines. (A) Human Aγ transgene (hγ) and mouse  gene (m) expression are shown from two embryos or fetuses at each time point for the wild-type HS3ɛγ construct carried by line 2649. The band protected by the mouse ζ probe is not shown but was included in the calculations in Table 1. (B) Human Aγ transgene (hγ) and m expression in animals from HS3ɛγ^−1086Mut line 4485. (C) Human Aγ transgene (hγ) and m expression in animals from HS3ɛγ^−1086Mut line 4456. Y = yolk sac; L = fetal liver; 4WB = blood from 4-week-old pups.