MAMMALIAN RADIATION GENETICS 



147 



Fig. 19. Neonatal, infant, and childhood mortality rates for inbred and outbred 



POPULATIONS OF MICE COMPARED TO UNITED STATES POPULATION. 



_# U S POPULATION 1956 



_j}. Fj MOUSE POPULATION (All 



O Q INBRED MOUSE POPULATION (L.it... ol 7. 8. & 9) 



MOUSE DAYS 

 MAN YEARS 



(Age scales adjusted to maximize comparability.) 



Growth and maturation. — Although there are no special genetic techniques required 

 for studies in this category, a deficiency of information still remains. Russell 1134 has 

 reported that mutants at the piebald locus nearly always show a poor rate of growth and 

 an associated higher mortality. The data of Boche et al. 113 did not indicate a growth 

 decrement, however. Possibly most effects on these traits will be due to a few major 



