Variations in the generation times of a strain of rat sarcoma cells in culture

The generation times of eight families of rat sarcoma cells in tissue culture were followed over five generations by time-lapse microcinematography. The mean generation time for seven of these families was 13.25 hr with a standard deviation of 2 hr and for the eighth family, 21.6 hr with a standard deviation of 4 hr. The correlation between the generation times of sister-sister was much greater than for mother-daughter pairs. These results were compared with those published for other cell lines and microorganisms and it was concluded that the source of variation is a combination of genetic and nongenetic factors.