2 DNA Reassociation and RNA Hybridisation of Bacterial Nucleic Acids

Abstract

Publisher Summary This chapter discusses the deoxyribonucleic acid (DNA) reassociation and ribonucleic acid (RNA) hybridization of bacterial nucleic acids. The elucidation of the structure and the physical properties of deoxyribonucleic acid (DNA) and ribonucleic acids (RNAs) has enabled investigators to compare directly the sequence similarities in these molecules from one organism with those from another. These comparisons, DNA reassociation or RNA hybridization experiments, are measurements of the pairing of two DNA fragments or the pairing of an RNA molecule with a fragment of DNA. The specific pairings are between the base pairs adenine (A) and thymine (T) [or uracil (U) in RNA] and between guanine (G) and cytosine (C). The final success of the methods and procedures described in this chapter depends upon the initial growth of the bacterial cells and the isolation of DNA or RNA from them. Although techniques for following the growth of bacterial cultures are beyond the scope of this chapter, their importance cannot be overemphasized. Many organisms are fastidious and grow very slowly or to a low turbidity, others tend to die very rapidly after reaching stationary phase, while others may enter a sporulation phase.