within the variable domains by conserved framework regions.Tthe heavy chain locus contains about 65 different variable domain genes that all differ in their CDRs.Combining these genes with an V(D)J recombination the heavy chain are shown in red PDB:1GT) immunoglobulin heavy or light chain is encoded in several pieces be(V (e variable (V).div ersity(D)and joining ()segments. aa084H54H0 6行 segments exist and are tandemly arranged in the genomes of ③： mammals.In the bone marrow,each developing B cell will 70 as emble ar region by randomly a国÷1 copies of each tvpe of and different of gene segments can be used to generate each immunoglobulin va region s pro ss ger erates a huge num t antiger al ombinatio (i.e.V2 family)for lambda light chain immunoglobulin is coupled of-9. with the activation of microF ional imn onyone kind of variable chain. Somatic hypermutation and affinity maturation pgactvaionwihaniger Follow B cells begint o pro rate rapidly. n these rapidly dividing cel s,the genes called somr mutation (SHM).SHM sults in approximatelyone eotide cha er celdivisionsa consequence.any daughter Bcells will acquire slight amino acdd variable domains of their antibody chains. This ser ngerinr h arfinity)cls thateir dies on their surface will receive d wi erea affinity not ntibodies to