Abstract
Although the inheritance patterns of cleft lip with palate (CLP) in mice and humans have been investigated for many years, the results appear to be controversial. The present study attempted to detect the inheritance pattern of cortisone-induced CLP in mice using genetic crosses between A/WySn (A) and C 3 H/He (C 3 H) strains. The F1 hybrids from a reciprocal cross between A and C 3 H were raised, and the reciprocal F1 and A/WySn were used to produce such as[A×F1(A×C3H)], [A×F1(C 3H×A)], [F1(A×C3H)×A]and[F1(C3H×A)×A]N2 backcross embryos. Pregnant mice were injected on days 11 through 14 of the gestation period with 100 mg of cortisone per kg of body weight. The frequency of CLP was observed among each group of embryos that attained at least Day 18 of development. In the A/WySn strain, the frequency of CLP was 11.3%. CLP was not found between the C 3 H/He and F1 hybrid. On the other hand 3.6% (37/1031) in N2 backcross embryos, and the frequencies in N2 of 4 groups were 1.7%,4.7%,3.3% and 4.2%, respectively. Among 37 N2 embryos with CLP, the female(18) and male(19) embryos segregated according a1: 1 ratio of_??_: _??_based on Mendelian expectations. These results suggest CLP was caused by autosomal recessive inheritance in mice.
