Abstract
Lambda-specific RNA extracted from lysogenic bacteria hybridizes specifically with fragments of lambda DNA containing 43 per cent GC (guanine plus cytosine). Therefore genes known to function in the prophage state (c(I) and rex) lie 0.38 +/- 0.08 fractional molecular length from the right end of the lambda DNA molecule, according to the compositional map of Skalka, Burgi, and Hershey.