Assume that blood type is inherited as A and B dominant over O, but A and B incompletely dominant over each other. Genotypes AA
and AO are then phenotypically type A, genotypes BB and BO are type B, genotype AB is type AB and genotype OO is type O blood. A man with type A blood marries a woman with type A blood. They have their first child as type O blood. What are the genotypes of the father, mother and baby? Father ___
Mother ___
Baby ___
This question involves blood type in humans where blood types A and B are dominant over blood type O, but A and B codominant. In this blood group system:
- Genotypes AA and AO are phenotypically type A
- Genotypes BB and BO are type B
- Genotype AB is type AB
- Genotype OO is type O
According to this question, a man with type A blood marries a woman with type A blood. They have their first child as type O blood. This means that both parents of this child are heterozygous type A i.e. AO and AO. This is the only way the parents can have a child with type O (genotype OO). Hence,
There are gaps in the fossil record because many early forms of life were soft-bodied, which means that they have left few traces behind. What traces there were may have been destroyed by geological activity. This is why scientists cannot be certain about how life began.
