Germ
Line
Theory
According to this theory the basis for, antibody diversity is already present in the germ line. A segment of DIN A in the germ line specifies each unique amino acid sequence in the V region. This would imply that there is a very large- number of genes for the V region. An individual having 1.°3 genes for the H chains could, generate. 106 different antibodies, since each antibody consists of one type of L chain and one type of H chain.
Thus a separate gene is postulated for each different Land H chain. Thetotal number of genes needed for this would correspond to only a small fraction of the genome. Therefore, it is entirely possible that each different V region of the Land H chains is specified by a different gene. Each V region gene is assumed to be adjacent to, its respective C region gene. Another assumption of this model is that the genes coding for the different classes (kappa, lambda, gamma, alpha, mu, delta, epsilon) and subclasses of the C region are repeated many times over.
