Fetal Hemoglobin TBR problems

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If you have TBR please look at Bio Section 2, Passage 14 concerning Sickle Cell Anemia and HbF.

Please look at question #91. TBR says the answer to diagnose Sickle Cell Anemia is by RFLPs on red blood cell DNA and gel electrophoresis of hemoglobin samples from red blood cells.

HOW can RFLP tests be done on red blood cell DNA when RBC do not have DNA? I think TBR made a mistake here. I think the answer should be II only. Can anyone confirm?

Also, on question #92, TBR says HbF does not bind 2,3-BPG, but in my biochem textbook it says that HbF does bind 2,3-BPG to a lesser degree than adult HB. Is this too another area of discrepancy?

Please confirm.

 

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If you have TBR please look at Bio Section 2, Passage 14 concerning Sickle Cell Anemia and HbF.

Please look at question #91. TBR says the answer to diagnose Sickle Cell Anemia is by RFLPs on red blood cell DNA and gel electrophoresis of hemoglobin samples from red blood cells.

HOW can RFLP tests be done on red blood cell DNA when RBC do not have DNA? I think TBR made a mistake here. I think the answer should be II only. Can anyone confirm?

Also, on question #92, TBR says HbF does not bind 2,3-BPG, but in my biochem textbook it says that HbF does bind 2,3-BPG to a lesser degree than adult HB. Is this too another area of discrepancy?

Please confirm.

This is what I learned in Biochemistry as well. Fetal Hemoglobin binds 2,3-BPG with less affinity relative to adult Hb. (Essentially the main reason why oxygen binds to Fetal Hb with increased affinity over adult Hb).

Sickle Cell Anemia is due to a mutation for a gene that encodes the beta subunit of hemoglobin. Individuals who have two mutated forms (ie. is recessive), will have Sickle Cell Anemia. Like you mentioned, RBC's lack a nucleus (lost during maturation process) and therefore carry no DNA. However, because every cell in our body (excluding germ cells) has the same DNA (just expressed differently), you can technically take the DNA from any cell, even the progenitor cell for RBC's, isolate the gene of interest, and subject that to gel electrophoresis.