[Properties of the F' factors formed in crosses of E. coli Hfr donor cells with recipient cells by means of defects in recombination]

Abstract

Meriploids isolated from the crosses of donor cells HfrH, KL-96, KL-99 and the recipient cells AB 2463 recA carried sex factors of different structures (different in length) and activities: 1) typical F1-factors with the proximal chromosomal markers; 2) "long" F1-factors of different structures with defective genes, which controlled sensitivity to phagef2; 3) "long" F1-factors of different structures with defective genes, which controlled conjugation transfer. Chromosomal markers can be incorporated into the sex factor regardless of their position in respect to the sex factor in the initial Hfr cells. Defects of the sex factor proper in the genome are accompanied by the loss of some chromosomal genes incorporated into the sex factor. At the same time the typical F'-factors preserve their structure completely.