a general protocol , modified from the one described by clive and spector ( mutat res 31:17-29 , 1975 ) , was followed by two laboratories , litton bionetics , inc. , and sri international , to evaluate 63 coded chemicals from 16 chemical classes for mutagenic activity at the thymidine kinase locus in l5178y tk+/- 3.7.2c mouse lymphoma cells .
C1708726
locus
C0007634
cells