1 Why might it not be surprising that a newborn expresses a

1. Why might it not be surprising that a newborn expresses a different gene coding for the non-alpha hemoglobin subunit (called beta in adults) than is typically found in adults? (Hint: think enviromental differences). Provide the appropriate citation to validate your answer. Must be in your own words.

2. Describe the link between malaria and SCA. What is the relationship of these two diseases? Again be descriptive, in your own words (2-3 sentences) and please provide citiation used.

Solution

1.Fetal hemoglobin is present in the newborn as opposed to adult hemoglobin. Fetal hemoglobin has higer affinity to oxygen when compared to adult hemoglobin. Since the foetus has to obtain oxygen by diffusion from the maternal oxygenated blood from the placenta, fetal hemoglobin must have higher affinity. Reference : http://www.embryology.ch/anglais/fplacenta/physio02.html

2.People suffering from Sickle Cell Anemia are resistant to malaria. Sickle cell hemoglobin strongly induces to expresses an enzyme called heme oxygenase 1 (HO-1). This enzyme produces carbon monoxide gas which decreases the circulation of free heme. So plasmodium cannot get hold of hemoglobin and it cannot infect new rbc. Sickle Hb also has immunoregulatory function which further limits the disease severity.

Reference : http://www.cell.com/cell/fulltext/S0092-8674(11)00384-9