On the location of palindromes in immunoglobulin genes.

We present a statistical method for detection of palindromes in mRNA or DNA, starting from the protein sequence. Analysis of immunoglobulin genes by this method demonstrates that palindromic sequences are not randomly distributed. They are located at each side of the hypervariable regions in the variable (V) genes, whereas no such regular design is observed in the constant (C) genes. In addition, palindromic sequences overlap the V-C junction in all immunoglobulin classes and significant palindromes are present near residue 216 of the heavy chain, which is the end of deletions in many heavy chain diseases. The relevance of these palindromes to gene translocation and generation of diversity in antibodies is discussed.