Physicochemical measurement of the base composition of mRNA-related sequences of the human α and β globin genes

Hybrids formed between human α and β globin cDNA and total human cellular DNA have been studied by thermal denaturation and cesium chloride density gradient centrifugation. From these studies, the weight average G+C content of human α globin cDNA has been determined to be 62%±2% and that of human β globin cDNA 51%±2%. These values correlate well with the results of G+C content of the human α and β globin cDNAs as determined by direct nucleotide sequence analysis of the cDNAs. Thermal denaturation and cesium chloride density gradient centrifugation of DNA-cDNA hybrids can therefore provide accurate information on the base composition of mRNA related sequences of any single copy gene for which a relatively pure cDNA can be obtained, without the necessity for direct nucleotide sequence analysis.