Influence of sex‐linked genes on embryonic sensitivity to cortisone in three strains of mice

It was postulated that sex‐linked genes affecting embryonic sensitivity to cortisone‐induced cleft palate and cortisone‐induced resorption might differ between inbred mouse strains showing pronounced reciprocal effects. The three strains tested were the A/J (A), C57BL/6J (B), and C3H/HeJ (C), whose sensitivities to cortisone‐induced cleft palate had been shown to be: A > C > B. The sensitivity of reciprocal A × B and B × C hybrid embryos was matroclinous; of reciprocal A × C embryos, patroclinous. Backcrosses of reciprocal F₁ hybrid males to inbred females were used to test the hypothesis of sex‐linkage with respect to the incidence of cortisone‐induced cleft palate, cortisone‐induced resorption, and the overall level of cortisone‐induced fetal damage. The results were consistent with the hypothesis that sex‐linked genes affecting embryonic sensitivity to cortisone‐induced cleft palate, but not to cortisone‐induced resorption, differ in the three strains.