A NEW MUTATION IN THE MOUSE

Abstract

A new mutation (Sd) is reported which in heterozygous condition produces a short-tail or taillessness, abnormalities of the spinal column, defects of the kidneys and lowered viability after birth. In homozygous condition it is entirely lethal, the young being born in normal proportion (152 Sd Sd, 328 Sd x, 142 x x) but dying within 24 hrs. of birth. The homo-zygotes are tailless, have spina bifida, and lack kidneys and external genitalia. The effect of the hetrozygous condition was enhanced by the genes of the Bagg inbred stock so that it now resembles a dominant lethal. Data given indicate that Sd segregates independently of another short-tailed mutation T, and of the dominant Caracul Ca.