Cloning and Nucleotide Sequence Analysis of Human Embryonic ζ-Globin cDNA

Clones of human embryonic α-like ζ-globin cDNA were isolated, by detection using cross-hybridization to human α-globin cDNA probes, from a cDNA library derived from the mRNA of the human erythroleukemia cell line K562. Nucleotide sequence analysis of these cDNA clones revealed a coding sequence that corresponds perfectly to the independently derived amino acid sequence of the human ζ-globin chain. Comparison of the nucleotide sequence of human ζ-globin cDNA with that of human α-globin cDNA confirmed previous estimates of very distant evolutionary divergence between the human ζ- and α-globin genes. Nevertheless, the human ζ-globin cDNA sequence shares a remarkable similarity to that of the α-globin gene in its codon usage, high G + C base composition, and lack of bias against usage of CG dinucleotides.