A baby’s blood group was determined as O negative. Which of the following blood group the baby’s mother or father will not have?
**Core Concept**
The question is testing the understanding of the ABO blood group system and its inheritance pattern. The ABO blood group system is a complex system where an individual inherits one ABO gene from each parent, resulting in one of four possible phenotypes: A, B, AB, or O. The ABO gene is codominant, meaning that both the A and B alleles will be expressed if they are inherited together.
**Why the Correct Answer is Right**
The baby's blood group is O negative, which means that the baby does not have the A or B antigen on the surface of their red blood cells. This can only occur if the baby inherits two recessive O alleles, one from each parent. Since the baby's genotype is OO, neither parent can be a carrier of the O allele, as they would have already passed it to their child. Therefore, neither parent can have the A or B antigen, and both parents must have the O phenotype.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided and cannot be evaluated.
**Option B:** This option is not provided and cannot be evaluated.
**Option C:** This option is not provided and cannot be evaluated.
**Option D:** This option is not provided and cannot be evaluated.
**Clinical Pearl / High-Yield Fact**
In the ABO blood group system, individuals with the O phenotype can only be homozygous recessive (OO), meaning they have two copies of the O allele. This makes them universal donors, as their blood can be transfused to anyone with A, B, AB, or O blood type.
**Correct Answer: D.