This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
[{'content': 'Sickle cell anemia is due to which type of mutation? \nSelect and explain. \nA. Frame-shift mutation, B. Base substitution mutation, C. Trinucleotide repeat, D. Splice site mutation', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Base substitution mutation Sickle cell anemia is a hereditary hemoglobinopathy, i.e., the type of disease characterized by production of defective hemoglobin. Sickle cell anemia results from mutation in b-globin gene. It is caused by a point mutation (Base substitution mutation) at the sixth position of the b-globin chain leading to subsitution of a valine residue for a glutamic acid residue resulting in sickle hemoglobin (HbS). Sickle cell anemia is an autosomal recessive disorder. If an individual is homozygous for the sickle cell mutation, almost all the hemoglobin in the red cell is HbS. In heterozyogotes, only about 40% of the hemoglobin is HbS, the remainder being normal hemoglobins.", 'role': 'assistant'}]