Chapter 17
Recombination and Transposition at the Molecular Level
Study Outline
I. Homologous Recombination
A. The staining of harlequin chromosomes can reveal recombination between sister
chromatids
B. The Holliday model describes a molecular mechanism for the recombination process
C. More recent models have refined the molecular steps of homologous recombination
D. Various proteins are necessary to facilitate homologous recombination
E. Gene conversion may result from DNA mismatch repair or DNA gap repair
II. Site-Specific Recombination
A. The integration of viral genomes can occur by site-specific recombination
B. Antibody diversity in the immune system is produced by site-specific recombination
III. Transposition
A. McClintock found that chromosomes of corn plants contain loci that can move
B. Transposable elements move via one of three transposition pathways
C. Each type of transposable element has a characteristic pattern of DNA sequences
D. Transposase catalyzes the excision and insertion of transposable elements
E. Replicative transposition requires both transposase and resolvase
F. Retrotransposons use reverse transcriptase for retrotransposition
G. Transposable elements may have important influences on mutation and evolution
H. Transposons have become important tools in molecular biology