Immunodeficiency diseases arise when individuals lack one or more components of their immune system, and are identified by an individual's history of persistent or recurrent infections. Some genetic defects (mutations or small deletions) can cause profound defects in an immune cell population; alternatively, in some cases, such small defects occur that there is no visible effect on immune responses. The diagram in Figure 1 shows simplified versions of the immunoglobulin heavy chain locus, the T-cell receptor chain locus, and the locus encoding the RAG-1 and RAG-2 recombinases. For the sake of this question, imagine that these diagrams represent all of the gene segments present in the immunoglobulin heavy chain and T-cell receptor chain locus. RSS with 12-nt spacer #F V VVV V42 Vp1 RSS with 23-nt spacer Immunoglobulin heavy chain locus (IgH) V2 V T-cell receptor locus V3 D1 RAG-1 Dp1 RAG-1/2 locus Figure 1 RAG-2 JHT 142 J2 JE You now analyze five individuals, each of which has a single inactivating mutation in a region of one of these three loci. These mutations are each indicated by a red 'X' in Figure 2, and are numbered 1-5. For each of these inactivating mutations, indicate the alterations and/or defects that would be seen in the repertoire of antigen receptors found in mature B and T cells in that individual. Also, for each mutation, indicate whether the individual would likely show any immunodeficiency, such as a history of recurrent infections. RSS with 12-nt spacer 76 V1 V RSS with 23-nt spacer Immunoglobulin heavy chain locus (IgH) V V2 V2 V43 V3 RAG-1 D1 T-cell receptor locus D1 RAG-1/2 locus Figure 2 RAG-2 small deletions or J1 42 Jp1 Jp2 Prompts Where is the deletion/inactivating mutation in terms of segment and locus? In what way will this deletion/mutation affect DNA recombination at this locus? Will antigen receptor production be affected? Will the deletion/mutation affect B cell repertoire, T cell repertoire, or both? To what degree? Will the individual show any immunodeficiency? Could you rank the severity of the immunodeficiencies in the five individuals?