In Ligase Chain Reaction theclinical sample is prepaed according to protocol to which liberates the DNA preseint in the sample the prepared clinical sample is added to reaction mixture containing thermostable DNA ligase a vast excess of two double strand oigonucleotide Probes specific to the pathogen to be detected and NAD. The two probes are blunt ended represent contiguous segments of the pathogen genome and each of them long 15 to 30 pair long therefore, the target sequence long the target sequence must be specific to the pathogen to be detected therefore the reaction mixture is beatede in thermocycler to ensure strand separation of both the target DNA and the probes the temperature is then lowereed to 55 temperature to allow the probes to pair with the target DNA now joins the adjacent of one strand of probe of the complementary strands of the two probes are also similarly joined the product of ligation of the two probes is called amplicon.
THE second cycle of LCR is initiated through heating the reaction mixture 94 temperature. In this and subsequent cycles of LCR both the target DNA and the amplicon serve as targets for probes and a result for aomplification this leads to an exponential amplification of the amplication. The amplicons are detected by gel electrophoresis of the reaction mixture ethidium bromide staining and viewing under UV light.
LCR is highly efficient it deetects target molecules in sample having 200-300 targets. It is highly specific and rarely produces false positive signals which is in contrast to PCR. The LCR producere allows automated detection by employing flouresence or hapen labelled probes LCR has been used to detect wide variety infectious agents such as chlamydia trachomatis mycobacterium tuberculosis herpes simplex virus hepatitis B virus Hepatitis C virus etc.
THE second cycle of LCR is initiated through heating the reaction mixture 94 temperature. In this and subsequent cycles of LCR both the target DNA and the amplicon serve as targets for probes and a result for aomplification this leads to an exponential amplification of the amplication. The amplicons are detected by gel electrophoresis of the reaction mixture ethidium bromide staining and viewing under UV light.
LCR is highly efficient it deetects target molecules in sample having 200-300 targets. It is highly specific and rarely produces false positive signals which is in contrast to PCR. The LCR producere allows automated detection by employing flouresence or hapen labelled probes LCR has been used to detect wide variety infectious agents such as chlamydia trachomatis mycobacterium tuberculosis herpes simplex virus hepatitis B virus Hepatitis C virus etc.
