Genetic Analysis of the Induction of Tumors by Methylcholanthrene

Abstract

13 mutations involving coat color have appeared in the untreated descendants of mice receiving methylcholanthrene. The 1st mutant obtained occurred in a subline of the NHO strain which had been subjected to methylcholanthrene in both parents for 12 generations. An increased growth rate, attainment of a larger body size and wt., precocious sexual activity, large 1st litters and increased susceptibility to induced local tumors by methylcholanthrene have also been obtained. These suddenly appearing color mutations have occurred, either alone or in association with one or more of the changed biological characteristics enumerated above. Thus there is evidence that methylcholanthrene has affected the germ plasm by bringing about germinal or point mutations and perhaps other undetd. effects. It is highly probable, therefore, that methylcholanthrene may also bring about malignancies in tissues by causing somatic mutations to arise in them.