Book Viewer

Short Contents | Full Contents | Other books @ NCBI

| Modern Genetic Analysis Chapter 9. The Genetics of Bacteria and Phages Bacterial Conjugation Figure 9-5. The transfer of E. coli chromosomal markers mediated by F. (a) Occasionally, the independent F factor combines with the E. coli chromosome. (b) When the integrated F transfers to another E. coli cell during conjugation, it carries along any E. coli DNA that is attached, thus transferring host chromosomal markers to a new cell. (c) In a population of F+ cells, a few cells will have F integrated into the chromosome; these few cells can transfer chromosomal markers. Therefore, when a population of F+ cells is mixed with a population of F cells, a few F cells will acquire markers from the donor. (d) Occasionally, the integrated F can leave the chromosome and return to the cytoplasm. In rare cases, F can carry host genes with it, incorporating them into the circular F, which is now termed an F. The F can transfer these genes at high efficiency to other cells, because they are part of the F genome.

© 1999 by W. H. Freeman and Company. All rights reserved.