RECOMBINATION SIGNATURE OF GERMLINE IMMUNOGLOBULIN VARIABLE GENES

In human and mouse, the germline contains a tandem array of highly hom ologous variable (V) gene elements which encode part of the antigen-bi nding region of the antibody protein. During evolution this array appa rently arose by gene duplication followed by diversification of duplic ated genes via point mutation and recombination. Analysis of germline V gene sequences using a novel algorithm shows that major recombinatio n sites coincide with the borders of the leader intron and the cap sit e, consistent with the hypothesis that over evolutionary time cDNA der ived by reverse transcription of pre-mRNA in B lymphocytes has recombi ned with germline DNA.