Mother is B blood type and Father is AA blood type?

Answer 1

Your dad = B, he could be BB or B0

Your mum= AB she has AB

Each of them transferres one allel to you, so you could be:

A+B = AB

B+B = B

A0 = A

B0 = B

So you must be AB, B or A :)

RV

Answer 2

This can be explained by using thePunnett (pew-NET) square. Unfortunately, I'm not good enough to create a pretty one here, so forgive the crudity of my attempt!

Everyone has two alleles (genes) that determine both the blood type (ABO) and Rh type. You inherit one of each from each of your parents. The Punnett square is a way to conceptualize how this works. Start with the ABO type, and draw a tic-tac-toe board:

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Mom is B (ignore the +/- for now), which means that she can have either of the following combinations of alleles (genes): BB, BO. Dad is A, so he can be either AA or AO. The O type is recessive, and only occurs if the person has O for both alleles. With this info, and the fact that you're B, I'm going to say (and I'll show you why in a second) that your mom can be either of the two types given above, but your dad must be "heterozygous" (has two different alleles, as opposed to "homozygous", where the same allele is expressed twice: BB). So, how did I do that? Here are the squares:

...| B | B <- Mom's blood type (possibility 1)

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A |AB|AB

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O |BO|BO

...| B | O <- Mom's blood type (possibility 2)

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A |AB|AO

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O |BO|OO

What this shows is Mom at the top and Dad down the left. Each square beneath gets filled in with the combination of the row and column represented. The top square shows Mom as homozygous (again, has both "B" alleles). This means any offspring have a 50% chance of being B blood type (the two BO squares) and 50% chance being AB type. The bottom square is the heterozygous pattern for Mom. Now there's a 25% chance than any offspring will have one of the available blood types (A, B, AB and O). That's the easy part.

The Rh factor (the "positive" or "negative" aspect of your blood type) is similar, but instead of A's, B's and O's, we need to consider Dominant versus Recessive. the Rhesus factor (what Rh is an abbreviation of) is dominant, so if one of the two alleles has it, then the person is said to be positive. If both alleles have it, then again, the person is positive. The only way for one to be negative is if both alleles are the recessive type. Let's do another Punnett square, this time "R" means dominant allele and "r" means recessive (R for Rhesus). Since you're negative and both parents are positive, I'm going to jump ahead and tell you that each of your parents is heterozygous dominant (Rr). I'll also show a square where one of your parents is homozygous dominant (RR) to prove it.

...| R |r

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R |RR|Rr

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r |Rr|rr

Since the Rh factor is dominant (anywhere you see a "R" means that kid is positive), there's a 75% chance (3/4 squares) that offspring will be positive, and a 25% chance that they will be negative. This is the only combination of positive parents that can produce a negative child. Here's the proof:

...| R |R

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R |RR|Rr

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r |Rr|rR

By making Mom (or Dad!) homozygous dominant, we've changed the table and the probabilities- now it's IMPOSSIBLE for these two parents to have an Rh negative child, since every inner square (the offspring) has at least one capital R.

Just remember that these are probabilities, so if you happen to have 3 siblings, you're not guaranteed to see every possible combination! Each time your parents have a child, each child has the same probability of inheriting the above parameters, so if you were worried that your dad may not be your father, don't! It's perfectly explainable! :)

Answer 3

If the mother is homozygous (BB, AA): the child is AB.

If the mother is heterozygous (Bi, AA): the child is A or AB.

Answer 4

If both parents are AB, then the offspring can be AB or A or B.