SOMATIC HYPERMUTAGENESIS IN IMMUNOGLOBULIN GENES .3. SOMATIC MUTATIONS IN THE CHICKEN LIGHT-CHAIN LOCUS

We report a new approach based on the Monte Carlo method, to analyze g ene conversion. With this, we have examined 235 somatic mutations in t he chicken V-lambda gene and found that about 75% of somatic mutations significantly correlated with donor sequences in 25 pseudo V-lambda g enes (set C) versus about 25% that did not (set N). The RGYW and TAA c onsensus sequences of mutational hotspots were earlier revealed in mam malian V genes. Analysis for correlation between somatic mutations in the V-lambda gene and the consensus sequences showed that the somatic mutations of set N were correlating with the consensus sequences (P(W < W-random) < 0.01) and the somatic mutations of set C were not. Based on further statistical analysis, we suggest that there must be at lea st two mechanisms responsible for somatic hypermutagenesis in the V-La mbda gene: gene conversion and another, which accounts for the elevate d frequencies of somatic mutations at the RGYW and TAA consensus seque nces.