Deletions in Immunoglobulin Polypeptide Chains as Evidence for Breakage and Repair in DNA

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Science  07 May 1971:
Vol. 172, Issue 3983, pp. 574-577
DOI: 10.1126/science.172.3983.574


The partial sequence of the light chain of the myeloma-like immunoglobulin Sac shows a large deletion in its variable region. The sequence provides evidence that the corresponding gene was formed by the repair of DNA broken at nonhomologous positions. Data from other immunoglobulin (heavy) chains containing large deletions are compatible with their genes also being the result of DNA breakage and nonhomologous repair. Single homologous reciprocal exchanges in DNA networks at immunoglobulin loci could be the cause of the nonhomologous breaks. The relevance of these events to the generation of normal antibody variability remains to be determined.