Gene transmission

The high fidelity semiconservative replication of DNA ensures transmission of genes from parents to progeny without change this is the reason for stability of genetically controlled phenotypes over generations. However, a low frequency per gene per generation of changes occur in genes naturally these mutations are the ultimate source of all the heritable variation observed inm living forms. Another source of genetic variation si recombination between genes. In eukaryotes recombination occurs regularly during the meitotic for the formation of gametes involved in sexual reproductin the has been highly successfully exploited by plant and animal breeding programmes. In prokaryotes, on the other hand, recombination occurs when foreign DNA is brought into a cell during any of the folowing three events transformative transduction and conjugation in gransformation DNA is directly takes a by the cell and portion of ti becomes integrated in the cells chromosome a process of recombination. But in case of transduction, the DNA is transferred ffrom one cell into another by a virus it may either be generalized or specialized conjugation on chromosome may be transferred into the reciepent cell often even large plasmids are exchanged. SEgments of the transferred chromosome become into the chormosome of the recipient cell by a process of recombination.