Lethality and abnormal condition of the pelage of the latvian mouse (dominant-naked)

Summary and Conclusions

The above-described examination of dominant-naked mice shows that with homozygotes (NN) lethality occurs in various degrees, dependent on the combinations of parents and grandparents. The difference in lethality is manifested not only in the percentages but also in the difference in age when the young die. These two manifestations run parallel.

The lethality for the greater part becomes manifest postnatally, but is already determined prenatally, also by the nature of the mother, who herself is again more or less favourably influenced by the nature of her parents.

The postnatal influence of the mother, viz. feeding and care, is of little or no value for the lethality, but apparently there is a clearly detrimental influence of the milk of homozygous naked females on the pelage of normal and heterozygous young.

On the ground of the observed facts the hypothesis is suggested that we have to deal here with a case of allelomorphism the gene B causing the production of a substance necessary for the normal hair growth and viability and the allelomorphB ₁ (=N) that of a quantitatively or qualitatively abnormal substance with consequent hairlessness and lethality.