“…In some strains, the H-2 or major histocompatibility complex (MHC) region has been implicated by the use of congenic strains (Bonner and Slavkin, 1975;Tyan and Miller, 1978;Erickson et al, 1979;Gasser et al, 1981Gasser et al, , 1991Gasser, 1994;Goldman et al, 1982;Melnick et al, 1981;Tyan and Tyan, 1993), and by analyses of backcrosses (Biddle and Fraser, 1977;Tyan, 1982, 1983;Tyan and Tyan, 1993). Genetic analyses have shown, however, that the differences between inbred strains of mice with respect to their incidences of steroid-induced cleft palate cannot be explained by only one or two genetic factors (Kalter, 1954;Francis, 1973;Biddle and Fraser, 1977;Liu and Erickson, 1986b).…”