Genetic recombination Genetic recombination involves the physical exchange of genetic material between genetic elements Homologous recombination results in genetic exchange between homologous dna sequences from two different sources. This type of recombination is extremely important to all organisms. However, it is also very complex. Even in the bacterium Escherichia coli there are at least 25 genes involved
Genetic Recombination Genetic recombination involves the physical exchange of genetic material between genetic elements. Homologous recombination results in genetic exchange between homologous DNA sequences from two different sources. This type of recombination is extremely important to all organisms. However, it is also very complex. Even in the bacterium Escherichia coli there are at least 25 genes involved
DNA A simplified version of one molecular mechanism Endonuclease nicks DNA of recombination. Homologous DNA molecules pair and exchange DNA segments Nick SSB protein SSB protein The mechanism involves breakage and reunion of paired segments. Two of the proteins involved, a single-stranded Strand nvasion binding(ssB) protein and the reca protein Development of cross.strat Note that there are two possible exchange outcomes, depending on which strands are cut during the resolution process. In Resolution Resolution one outcome the recombinant molecules atVsites have patches. whereas in the other the Patches two parental molecules appear to have been cut and then spliced together
A simplified version of one molecular mechanism of recombination. Homologous DNA molecules pair and exchange DNA segments. The mechanism involves breakage and reunion of paired segments. Two of the proteins involved, a single-stranded binding (SSB) protein and the RecA protein. Note that there are two possible outcomes, depending on which strands are cut during the resolution process. In one outcome the recombinant molecules have patches, whereas in the other the two parental molecules appear to have been cut and then spliced together
Detection of recombination In order to detect physical exchange of DNA segments, the cells resulting from recombination must be phenotypically different from the parents Strains that lack some selectable characteristic that the recombinants will possess. For instance, the recipient may not be able to grow on a particular medium, and genetic recombinants are selected that can Various kinds of selectable and nonselectable markers(such as drug resistance, nutritional requirements, and so on)may be used
In order to detect physical exchange of DNA segments, the cells resulting from recombination must be phenotypically different from the parents. Detection of Recombination Strains that lack some selectable characteristic that the recombinants will possess. For instance, the recipient may not be able to grow on a particular medium, and genetic recombinants are selected that can. Various kinds of selectable and nonselectable markers (such as drug resistance, nutritional requirements, and so on) may be used
Complementation This can be determined by a type of experiment called a complementation test Complementation was first used in diploid eukaryotic organisms
Complementation This can be determined by a type of experiment called a complementation test. Complementation was first used in diploid eukaryotic organisms
Genetic Transformation Transforma ee DNA Vrus irjection. disruption 四Q In prokaryotes genetic recombination is observed because fragments of homologous DNA from a donor chromosome are transferred to a recipient cell by one of three processes (1 transformation, which involves donor dna free in the environment (2)transduction, in which the donor dna transfer is mediated by a virus (3)conjugation, in which the transfer involves cell-to-cell contact
In prokaryotes genetic recombination is observed because fragments of homologous DNA from a donor chromosome are transferred to a recipient cell by one of three processes: (1) transformation, which involves donor DNA free in the environment (2) transduction, in which the donor DNA transfer is mediated by a virus (3) conjugation, in which the transfer involves cell-to-cell contact Genetic Transformation