◼ All DNA is recombinant DNA. ◼ Genetic exchange works constantly to blend and rearrange chromosomes, most obviously during meiosis, when homologous chromosomes pair prior to the first nuclear division. ◼ During this pairing, genetic exchange between the chromosomes occurs. This exchange, classically termed crossing over, is one of the results of homologous recombination
Although DNA replication, repair, homologous recombination occur with high fidelity to ensure the genome identity between generations, there are genetic processes that rearrange DNA sequences and thus lead to a more dynamic genome structure Two classes of genetic recombination for DNA rearrangement: • Conservative site-specific recombination (CSSR): recombination between two defined sequence elements • Transpositional recombination (Transposition): recombination between specific sequences and nonspecific DNA sites