# Why do we have blood types?  Do you know yours?



## Meanderer (Jul 16, 2014)

*More than a century after their discovery, we still don’t know what blood groups like O, A and B are for. Do they really matter? Carl Zimmer investigates.

http://www.bbc.com/future/story/20140715-why-do-we-have-blood-types

*


----------



## Falcon (Jul 16, 2014)

It says  "B"  on my dog tags.


----------



## Mrs. Robinson (Jul 16, 2014)

A+. Hubby is O+. When daughter #3 was pregnant,they discovered she was a negative blood type (can`t remember if she was A or O) but I freaked out a bit because I didn`t know two positives could have a negative blood type. I was afraid I wasn`t her mother  The doctors put my mind to rest though,absolutely possible.


----------



## Warrigal (Jul 16, 2014)

Why do some people have blue eyes, others brown and still others something intermediate like grey or hazel? It's just genetic variation, probably the result of long ago mutations.

The same is true for blood types, left and right handedness and a whole lot of other variations. For the sake of those who worry, these variations are controlled by pairs of genes and some genes are dominant and some recessive. For example a person with group A blood may be AA or AO. Similarly, for Group B the person may be BB or BO. If they have a child he/she could be AO (group A), BO (group B), OO (group O) or AB (group AB). It is perfectly possible for parents who are both rh+ to have a rh- child. 

What is the reason for genetic variability? Better survival value for a population because if something evolves that attacks all the people with Group A blood, then the people with Group O and Group B would still survive.


----------



## SifuPhil (Jul 17, 2014)

This is sad to say, but I've forgotten what my blood-type is. I think it's B+, but not sure ... that'll tell you how long it's been since I've been to a hospital or doctor's office ...


----------



## JustBonee (Jul 17, 2014)

I know mine is AB+ from being a blood donor for years.  Also they check when you are pregnant.


----------



## taffboy (Jul 17, 2014)

No I don't know my blood type.


----------



## Meanderer (Jul 17, 2014)

There are four major blood groups determined by the presence or absence of two antigens – A and B – on the surface of red blood cells:


*Group A – has only the A antigen on red cells (and B antibody in the plasma)*
*Group B – has only the B antigen on red cells (and A antibody in the plasma)*
*Group AB – has both A and B antigens on red cells (but neither A nor B antibody in the plasma)*
*Group O – has neither A nor B antigens on red cells (but both A and B antibody are in the plasma)*
*There are very specific ways in which blood types must be matched for a safe transfusion. See the chart below: 
http://www.redcrossblood.org/learn-about-blood/blood-types

*


----------



## Honey (Jul 17, 2014)

I'm AB+ too, years ago they used to send a car for me and take me to the Blood Transfusion Centre as this blood type was needed for pregnant ladies apparently


----------



## Meanderer (Jul 17, 2014)

Honey said:


> I'm AB+ too, years ago they used to send a car for me and take me to the Blood Transfusion Centre as this blood type was needed for pregnant ladies apparently


You don't want to be over-drawn at the Blood Bank!


----------



## JustBonee (Jul 18, 2014)

Honey said:


> I'm AB+ too, years ago they used to send a car for me and take me to the Blood Transfusion Centre as this blood type was needed for pregnant ladies apparently



I've been given reminder calls to come to the blood bank too.  They told me that AB+ is a little rare,  and they have a hard time keeping supplies on hand.  
I got a card in the mail one time that my donation saved a baby's life.  That was a good feeling.


----------



## Honey (Jul 18, 2014)

me too Bonnie!


----------



## Bettyann (Jul 20, 2014)

Mine is B negative...  Its important if you need a blood transfusion!


----------



## Warrigal (Jul 20, 2014)

Don't worry Betty. All blood transfusions require the donated blood to be tested against the recipient's blood before transfusing. I don't think they take your word for what blood type you think you are. I still have my Red Cross card although I'm no longer a donor but I doubt that they would even accept that as proof. My type is A+ but my daughter is O+ so I know that I cannot donate for her in an emergency.


----------



## debodun (Jul 21, 2014)

I even know my phenotype, I got an A+ from both parents.


----------

