Answer to Question #6657 in Microbiology for virginia

Question

describe how DNA hybridization can be used to show how closely two bacterial strains are related to one another

Answer 1

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.