In a PCR-RFLP assay using a restriction enzyme on DRB1*0701, how many bands would be expected in the gel analysis for a patient with HLA type DRB1*0101/DRB1*0701?

In a PCR-RFLP assay, the number of bands observed in gel analysis is determined by the specific alleles present and how the restriction enzyme recognizes and cuts the amplified DNA segments. For an individual with an HLA type of DRB10101/DRB10701, both alleles can produce distinct products when amplified.

The DRB10701 allele has specific recognition sites for the restriction enzyme used in the assay, which generates distinct fragments upon digestion. On the other hand, the DRB10101 allele will likely present different recognition sites and therefore, it will typically produce differently sized fragments when subjected to the same enzyme.

Since the individual is heterozygous for these two alleles, the enzyme will not only cut the DNA from the DRB10701 allele but also from the DRB10101 allele. This process will lead to distinct fragments corresponding to the different alleles. A thorough examination of both alleles and the specific cuts made by the restriction enzyme will result in multiple bands appearing on the gel.

Thus, it is expected that the combination of the fragments from both alleles will produce a total of three distinct bands in the gel analysis: one associated with the DR