If One Parent Is Blood Group Ab Positive And The Other Parent Is B Positive, What Is The Blood Type Of The Child?


3 Answers

Katie Harry Profile
Katie Harry answered
The child would have either the blood group A, B or AB. The rhesus factor may be positive or negative in the child.
See, the blood groups are determined by what alleles each DNA strand carries in a person. The alleles are A, O, and B. These may be in combination with each other to give different blood types. It is important to know that A and B are dominant. Thus whenever they are present, they are expressed. If there are both A and B present, they are co-dominant and form the blood group AB. Blood group O only occurs when both alleles are OO. Each parent passes only one strand on to the offspring in their gametes so that each person includes 50% DNA from each parent.
So, for blood group AB, the possible allele combination (genotype) is A B. For blood group B, the possible combinations are OB or BB.
Thus, if we put these in a punnet square, we see what offspring we may get:

Parents genotype   AB   BB
Gametes   A   B   B   B
Zygote/baby   AB   AB   BB   BB
Blood group of baby    AB  AB B  B
So, there is a 50-50 probability of the child being AB or B.

If, the parent with the blood group B has the genetic make up OB, then:
Parents genotype   AB   OB

Gametes   A   B   O   B

Zygote/baby   OA   AB   OB   BB

Blood group of baby    A  AB  B   B

So, there is a 50% probability of the child having the blood group B and 25% probability of the child having either blood group A or AB.
aileeny Profile
aileeny answered
The answer is no.///   AB man  can only pass on his  A or his   B  (not both together) as he has no o to pass on. //Even if the woman B was a carrier for o and passed this o on, the resulting child would be Ao  or Bo. O group has to receive the o from both parents (oo).///////Regarding the R H factor,  a child from this union can only be a RH neg. If both parents are carriers for neg, as (like the o grouping) neg. Is a recessive trait and a child needs to inherit neg from both be neg.

Answer Question