Abstract
In order to clarify the molecular basis of the heterogeneity of rat hemoglobins, two DNA clones containing the genes for adlut type β-globins were isolated from a rat genomic DNA library. The results obtained in the present experiments are summarized as follows.
1) Clone λ Rg β59 contained the gene for an adult rat β-major globin, IIβ, while clone λ Rg β45 contained the genes for two adult rat β-minor globins, IIIβ, and Oβ, respectively.
2) The entire nucleotide sequences of these genes were determined, indicating that the genes are all composed of 3 exons and 2 introns, and code for 146 amino acid residues. The genes exhibited structural features typical to known expressed β-like globin genes, implying that they are all functional.
3) The predicted amino acid sequences completely agreed with the amino acid sequences of IIβ, IIIβ and Oβ globins, respectively, which we isolated in a separate experiment.
4) Sequence comparisons of three rat globin genes with one another and with the known mouse β-major and β-minor globin genes showed the occurrence of interesting homologies between two species from evolutional aspects.
5) Southern hybridization analysis of the genomic DNA implies that a number of β-like globin genes other than the present ones exist in the rat genome.
