fluctuation analyses of zn ( smu/s gamma 2b ) tk1 infected 18-8tk- and 38b9tk- pre-b lines revealed htk gene inactivations with apparent frequencies of 5 x 10 ( -5 ) and 1 x 10 ( -5 ) events/cell/generation , respectively , while g-418 resistant ltk- fibroblasts lost the htk phenotype at an apparent rate of 4 x 10 ( -8 ) .
C0007634
cell
C0016030
fibroblasts