Table 1

Genotyping of progeny derived fromtace ΔZn/+ intercrosses. The numbers of viable progeny corresponding to each genotype are listed. Additional nonviabletace ΔZn/ΔZn fetuses are indicated in parentheses. Most tace ΔZn/ΔZn mice found alive at birth died within several hours (12). The six surviving tace ΔZn/ΔZn mice were either killed or found dead between P14 and P21. The genotyping assay could not distinguish between +/+ and ΔZn/+ on a p55−/− p75−/− background. Animal care was in accord with Immunex institutional guidelines. e, embryonic; P, postnatal; nd, not determined.

Background Age Total +/+ ΔZn/+ ΔZn/ΔZn
C57BL/6 × 129 e13.5–16.5100 25 52 20 (3)
e17.5–18.5 103 2359 17 (4)
P14–21 464 163 295 6
p55−/−p75−/− P14–21 51 nd nd  0