Abstract
This chapter describes the R looping and structural gene identification of recombinant deoxyribonucleic acid (DNA). The advent of recombinant DNA technology has made possible studies on the organization and expression of eukaryotic genes. In high concentrations of formamide, ribonucleic acid (RNA)–DNA duplexes have a higher thermal denaturation temperature than the corresponding DNA–DNA duplexes. When DNA and complementary RNA are incubated under these conditions, R loops are readily formed. For the formation of R loops with recombinant DNA, the procedure consists of incubating sufficient quantities of DNA with limited amounts of messenger RNA (mRNA) such that the rate of the reaction is DNA driven. The rate of R-loop formation is a sensitive function of the incubation temperature. The chapter discusses the R looping of histone plasmids.