How is antibody diversity generated? Two early theories: Germline hypothesis The genome contains many loci encoding antibody molecules B cells express one of these loci. Different B cells express different loci. Somatic mutation hypothesis There are a small number of antibody genes which undergo mutation as the B cell matures -thus giving rise to B cells expressing antibody of different specificity. How is antibody diversity generated? Two early theories: Germline hypothesis The genome contains many loci encoding antibody molecules. B cells express one of these loci. Different B cells express different loci. Somatic mutation hypothesis There are a small number of antibody genes which undergo mutation as the B cell matures - thus giving rise to B cells expressing antibody of different specificity