Chromosomes segregration and development in Caulobacter crescentus

The pattern of genome segregation to progeny stalked and swarmer cells of Caulobacter crescentus has been determined in a study of the localization of information in developing cells. The genome of stalked cells was labeled with ³H]deoxy-guanosine to mark one of the two DNA strands preferentially. The segregation of this labeled strand after one or more rounds of replication and division in non-radioactive medium was determined by (a) the rate of accumulation of radio-activity during three successive generations of swarmer cells released from labeled stalked cells which were attached to glass plates, and (b) electron microscopy autoradiography of stalked and swarmer cell progeny of labeled stalked cells. The results indicate that most of the DNA of a given age in C. crescentus segre-gates randomly to the two cell types at division, and that the genome probably segregates as a single chromosomal unit.