[ukmicky (OP)]

Good Morning campers
A not so quick question this time if i may.

Why are their different blood groups. has it got anything to do with where our ancesters came from. i.e africa, europe etc. do animals of the same species have different blood groups. and what is the difference between blood groups.

[RenRen]

Blood groups come from the kind of antigen on your red blood cells. Type A is one antigen (sugar molecule), type B is another, and type O is actually no antigen. Then you have the Rh-group, the Duffy, and all sorts of other blood groups. But ABO and Rh are the big ones because they must match your own group, or you risk developing an immune reaction against them.

Dogs and cats, and other mammals type as "O" not because they are O's like humans, but because they don't have the same antigens as we do. While it would be tempting to give someone this blood, the animal's blood has other antigens not like ours which would cause our immune systems to violently react against it, making us very, very sick.

As to the evolution of blood groups... We all have the genes to make A, B, or no (type O) blood, but only some get expressed. So it is safe to say that, yes, environmental pressures had something to do with it. To what extent? Well, it is known that certain bacterial infections, drugs, and animal venoms will change the antigen coating of your cells... So that could be an avenue. Does one type have an advantage over the other? Maybe.

For example, type O people can only get type O blood. Type AB people can get any type of blood. You would think that, as blood transfusions are more and more common to save people in otherwise life threathening situations, those with AB blood would be saved more often than those with rarer blood types, thus passing on the genes... But that's the catch. A type AB person can have children that are A's, B's, or AB's!