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BTD Forums  /  Live Right 4 Your Type  /  Family range of blood types
Posted by: Gale D., Thursday, August 13, 2009, 6:23pm
I am trying to understand blood typing. I asked my sisters about their blood type:

I am A-pos, my sister is A-pos, and our half-sister is also A-pos.

We all have the same mother.

Can we determine our parent's blood types with these three results?

We're waiting to hear from our brother and my biological dad.
Posted by: Heidi, Thursday, August 13, 2009, 6:48pm; Reply: 1
It is probably safe to guess that at least one parent is an A or AB but that is about as much as you could narrow it down. If I remember correctly A+O, A+B, A+A and O+AB can all produce A children.

I, along with my two sisters, are all A bloodtypes. Two of us are RH- and one RH+. My parents had their blood typed last summer and Mom is O+ and Dad is A+. I'd love to know my brother's type. I strongly suspect that he is an O like Mom. He fits the Hunter profile sooo well.
Posted by: Gale D., Thursday, August 13, 2009, 10:51pm; Reply: 2
ok, so how could I have an 0+ or 0- child?
Posted by: Lola, Thursday, August 13, 2009, 11:00pm; Reply: 3
if your recessive gene is o, making you an Ao, meaning one of your perents was an O

then you need an O partner and then you pray! ;D
Posted by: Gale D., Thursday, August 13, 2009, 11:02pm; Reply: 4
thanks!

I think my ex might be an 0.

So, the fact that I have an 0 child means definitely that my subtype is 0?

Could one of my parents be Ao or some other blood type to get this outcome?

You know that blood type testing kit that comes with the Shareright packet? Will that test just regular type, as in "A-positive" or will it test the subtype too as in "A+o"?
Posted by: Lola, Friday, August 14, 2009, 12:16am; Reply: 5
just regular

a serotyping panel requested at a lab will give you A subtype and RH factor
as well as secretor status and MN
Posted by: l3asu, Friday, August 14, 2009, 12:51am; Reply: 6
http://www.biology.arizona.edu/Human_Bio/problem_sets/blood_types/btcalcA_popup.html

Blood Type Calculator

I hope this will help narrow it down at least  :)
Posted by: Plucky, Friday, August 14, 2009, 12:58am; Reply: 7
Or your ex could also be an Ao.  Both of my parents are A's, Ao's to be precise; I have an A grandparent and an O grandparent on both sides of the family.
Posted by: C_Sharp, Friday, August 14, 2009, 1:10am; Reply: 8
The serotype panel will tell you if your subtype is A1 or A2.

Ao or AA is a genotype not a subtype.  You can find this out using genetic testing, but why bother? Your phenotype is A and unless you need to know the genotype (say for determining who was a possible parent) there is no point to pay for the test.

If an A parent has an O or a B child, that parent's genotype must be Ao.
Posted by: Chloe, Friday, August 14, 2009, 1:25am; Reply: 9
Quoted from C_Sharp
The serotype panel will tell you if your subtype is A1 or A2.

Ao or AA is a genotype not a subtype.  You can find this out using genetic testing, but why bother? Your phenotype is A and unless you need to know the genotype (say for determining who was a possible parent) there is no point to pay for the test.

If an A parent has an O or a B child, that parent's genotype must be Ao.



Would an A2 person have to have had an A2 parent?  Or just a parent who carries this subtype in their genes?

Posted by: C_Sharp, Friday, August 14, 2009, 1:36am; Reply: 10
A1 is dominant over A2.

Therefore an A1 mother and an A1 father could have an A2 child as long as the genotype of both parents were A1A2.
Posted by: Katsy, Friday, August 14, 2009, 2:44pm; Reply: 11
Quoted from Gale D.
ok, so how could I have an 0+ or 0- child?


My mom is Type A; we're not sure what my dad's type was. Three of four of us kids are A, with my eldest sister being O. She's married to an O, and since O is recessive, both her kids are definitely O's without testing (unless there is some sort of weird mutation thing that happened). A is a dominant type, but you have two blood type genes to pass to each of your offspring. You can be type A but have a recessive type O gene to pass on (from your parents, grandparents, etc. -- much like any other recessive trait, like blonde or red hair, blue eyes, etc., which is why some traits just "pop up out of nowhere" in families that haven't had red-heads in the family in living memory). Your child's father could be A with a recessive O like you; or Type B with a recessive O; or Type O. Your child had to receive a Type O gene from each parent, is all.
Posted by: Gale D., Saturday, August 15, 2009, 8:31pm; Reply: 12
I found out my daughter is 0-negative.

Can 2 parents who are positive produce a negative child?
Posted by: Tea Rose, Saturday, August 15, 2009, 8:37pm; Reply: 13
Quoted from Gale D.
I found out my daughter is 0-negative.

Can 2 parents who are positive produce a negative child?



Yes they can.  Rh + is dominant, but both parents would carry Rh - recessive genes.  This is the case with me and my husband, both O +, but both our sons are O - .

Tea Rose
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