DNA SEQUENCE ANALYSIS OF TWO BOVINE IMMUNOGLOBULIN CHGAMMA PSEUDOGENES

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Abstract
A bovine calf liver DNA library in .lambda.2001 bacteriophage has been screened with a human Ig.gamma.4 heavy-chain constant-region gene probe. Four hybridizing clones have been identified, and the DNA sequences in two these, which have high homology with CH.gamma. genes, are reported here. Within the bovine sequences, four separate exons can be identified, corresponding to the three CH domains and the hinge of gamma heavy-chain genes. Both of these genes contain atypical sequences around one or more of their exon/intron boundaries with consequent loss of splice sites, indicating that these are probably .gamma. pseudogenes. One sequence codes for a C-terminal peptide which matches the 18-mer C-terminal heavy-chain peptide of bovine serum IgG2, the other encodes a C-terminal peptide unknown in the bovine. These results suggest that evolutionary duplication of CH.gamma. genes has occurred in the bovine.