describe how DNA hybridization can be used to show how closely two bacterial strains are related to one another
To determine the relationship between microorganisms used method of DNA-DNA hybridization, which is based on the fact that the stability of DNA-DNA duplexes at a given temperature depends on the number of nucleotides forming complementary pairs. Obviously, the number of complementary nucleotides in the duplex where both strands are derived from the same DNA molecule (DNA of one organism) is equal to 100%. If both strands are of different origin (derived from different organisms), then, depending on the degree of relationship, the number of base pairs is less than 100%. Correspondingly heteroduplexes must decompose (melt) at a lower temperature than gomodupleksy. Moreover, the lower the melting temperature, the greater the difference in the two sequences.