Abstract
Chromosomes of sensitive and 5-fluorodeoxyuridine (FUDR) resistant sublines of mouse lymphocytic leukemia, P388, growing in vitro were observed. Chromosome number and karyotypes in the FUDR-resistant subline differed from those in the parental sensitive line both in the mode of total chromosome numbers (49 in the sensitive and 40 in the resistant sublines) and in the number of biarmed chromosomes (14 and 21, respectively). A sequential event of chromosomal damage, elimination and selection was considered as a cause of development of altered karyotypes in the FUDR-resistant subline.
