SOCR 330 Lecture Notes - Zygosity, Galactose, Anthocyanin
Document Summary
Three alleles control abo blood groups in humans: Ia and ib are codominant i is recessive. Abo antigens are carbohydrates on surface of red blood cells derived from precursor h molecule. Ia allele codes for transferase enzyme that adds n-acetylgalactosamine to h precursor. Ib allele codes for different form of transferase so adds galactose to h precursor ib antigen. Io codes for inactive form of transferase so h precursor unmodified (no antigens) Rare bombay phenotype has abnormal form of h so no sugar can be added. Bombay phenotype is type o regardless of genotype. John has blood group ab and his wife mary has blood group o. Their baby sam also has blood group o, which mary claims he must have inherited from her. John suspects, however, that mary has been more than friendly with their neighbor alan, and he thinks that alan may actually be sam"s father. Alan says this is not possible because his blood group is b.
