[Experimental study of the stability of expression of non-metrical threshold skeletal traits in inbred mice]

The influence of some environmental factors during prenatal development on manifestation of non-metrical threshold skeletal traits in BALB/c inbred mice was studied. The factors under study were: introduction of metilthiouracil into the diet of pregnant females; injections of pregnant females with adrenocorticotropic or parathyreoid hormones; keeping the females at low temperatures (two regimens). Offsprings of the females treated were examined for twenty five skeletal characters using Berry-Sjøvold's method. Despite the fact that their body weights decreased in all experimental groups, phenetical distances between the treated and control groups were much smaller than those between different inbred strains. Reliability of genetical interpretation of interpopulational differences in non-metrical skeletal traits is higher for the characters which are not correlated with total body sizes.