in hybrid cell line 20hl21-4 , which contains human chromosome 19 , uv-induced mutagenesis at the aprt , hprt and na+/k+-atpase loci was comparable to that in repair-proficient cho aa8 cells , whereas cell line 20hl21-7 , a reduced human-cho hybrid not containing human chromosome 19 , exhibited a hypermutable phenotype at all 3 loci indistinguishable from that of uv20 cells .
C1708726
loci
C0007634
cells