Method to estimate the numbers of ig and tor vgenes

using the nucleotide sequences of the V-genes of mouse lambda light chains, we have developed a simple method to estimate the numbers of V-genes of Ig and Ter. A standard triangular table listing the pair-wise differences is constructed for all complete distinct nucleotide sequences. A difference of 17 nucleotides suggests that the two sequences are most likely coded by two different genes. A lower limit can be obtained by using twice ofthat cutoff, i.e. 34 differences. Thus, we have: MOUSE HUMAN Ig lambda light chains (3 5) 37 - 65 Ig kappa light chains 76 - 134 27 - 71 Ig heavy chains 99 - 199 116 175 Tcr alpha chains 19 - 23 28 - 28 Tcr beta chains 13 - 16 27 - 31 Tcr gamma chains 4-44-5 Tcr delta chains 6-65-5 These numbers will certainly increase as more sequences become available. The estimations for human Ig heavy chains and human Ig lambda light chains are in good agreement with recent experimental studies of sequencing the regions containing these genes.