Genetics and blood type?

Question

How does it work? What changes the blood type in a child? Can a child with parents that are O+ have a child with O- or even something like A+?

Answer 1

There are 4 possible ABO phenotypes: A, B, AB, and O
There are 2 possible Rh factors: + and -
That makes 8 possible blood types (phenotypes): A+, B+, AB+, O+, A-, B-, AB-, O-

There are even more genotypes:
for Type A phenotype: You can have AA or AO
for Type B phenotype: You can have BB or BO
for Type AB phenotype: You can have only AB
for Type O phenotype: You can only have OO

Each parent will give one gene toward ABO blood type

If you mother is type O, then her genotype is OO, so her gamete will have type O
If your father is type A phenotype, then you don't know his genotype, it can be AA or AO, and his gamete can be A or O
so the resulting offspring can be
AO or OO, but not AA

O is a recessive, A and B are dominant
so if one parent is type A (genotype AA) and one is type B (genotype BB), the offspring will be type AB
but if parents are AO and BB offspring can be AB or B (genotype AB or BO)
for the most diversity, one parent AO one BO can have offspring of AO, BO, OO, or AB genotypes.

Type O parents will only produce type O offspring.

The Rh factor is as, + is dominant, - is recessive.
So ++ and +- genotypes express as + phenotype, whereas -- is the only way for - phenotype.

So two - parents only produce - offspring, but a + (could be ++ or +-) and - (only - -)parent can produce + (+-)and - (- -) offspring.

So O neg (OO--) and O pos (OO++ or OO +-) will produce OO ++ or OO +- which means only Type O positive.

Answer 2

ABO blood types are an example of co-dominance. The blood type of a child is determined by randomness and his or her parents' blood type. A couple with O+ can have an O- child if one of the parents is heterozygous for the Rhesus factor. A couple with O+ cannot have an A+ child, because O is recessive to A (or B), and both parents would be OO.

Answer 3

Your blood type never changes. A and B are dominant over O, so a person with type A blood can have genes AA or AO, a person with type B blood can have BB or BO, a person with type AB blood can have only genes AB, and a person with type O blood can have only genes OO.

So a man with type B blood and a woman with type A blood could have a child with type O blood.

Answer 4

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Answer 5

When a child is conceived it will have its fathers bloodtype, just like Jesus in the Bible. My father is O+ and all of his children have the same.