Why are there different blood groups?

Question

which was the original blood group?

and why can't people get blood transfusions from other blood grouped people?

thanks

Answer 1

The reason there are different blood type is because of mutations to DNA that have changed the function of an enzyme.  There is an enzyme that adds a final sugar onto the cells' identity marker glycoprotein.  In Type B blood, the enzyme adds galactose.  In Type A blood, the enzyme adds N-acetylgalactosamine, a modified version of galactose.  In type O blood, the enzyme is non-functional and adds no sugar.

We don't know for sure the original blood group, but it is most likely not O since it results from a loss-of-function mutation.  The most probable ancestral form is B because the frequency of the allele is greater in African populations.

People with Type A blood can get transfusions of A or O because A and O cells don't carry the alternate sugar on their antigens and therefore don't act as a signal that the cell doesn't belong.  Likewise, people with Type B can receive B and O.  People with Type O blood can only get other Type O because A and B cells both have different sugar signals.  However, people with Type AB can receive any blood group as a transfusion because their body recognizes them all as self cells.

Answer 2

The ABO system is the most important blood group system in human blood transfusion. The associated anti-A antibodies and anti-B antibodies are usually "Immunoglobulin M", abbreviated IgM, antibodies. ABO IgM antibodies are produced in the first years of life by sensitization to environmental substances such as food, bacteria and viruses. The "O" in ABO is often called "0" (zero/null) in other languages

Rhesus blood group system

Main article: Rhesus blood group system

The Rhesus system is the second most significant blood group system in human blood transfusion. The most significant Rhesus antigen is the RhD antigen because it is the most immunogenic of the five main rhesus antigens. It is common for RhD negative individuals not to have any anti-RhD IgG or IgM antibodies, because anti-RhD antibodies are not usually produced by sensitization against environmental substances. However, RhD negative individuals can produce IgG anti-RhD antibodies following a sensitizing event: possibly a fetomaternal transfusion of blood from a fetus in pregnancy or occasionally a blood transfusion with RhD positive RBCs.

Other blood group systems

Main article: Human blood group systems

The International Society of Blood Transfusion currently recognizes 29 blood group systems (including the ABO and Rh systems).[2] Thus, in addition to the ABO antigens and Rhesus antigens, many other antigens are expressed on the RBC surface membrane. For example, an individual can be AB RhD positive, and at the same time M and N positive (MNS system), K positive (Kell system), Lea or Leb negative (Lewis system), and so on, being positive or negative for each blood group system antigen. Many of the blood group systems were named after the patients in whom the corresponding antibodies were initially encountered.

Answer 3

We have different blood groups based on the number of Antigens and antibodies that are present in the blood cells.

  We say AB group when there is no antibodies and both antigens are present.  We would say O blood group when the antigens are absent what this would say is that the blood is grouped based on the Antigens, if there are just Antigens A present then its called A group blood and if there are just Antigen B then B group blood and if both are present then AB.. If none present then O group..

          I am not sure as to which is the original blood group but can make a wild guess it was AB because if u see the other groups then we can say that as generations passed on some developed more A group antigens and never took B to form a group. But for O group those species never inherited antigens from parents but just got the antibodies.

      Well this is what i know about the Blood groups.

Answer 4

I think the different blood groups came about because of genetic mutations that were then passed on through generations. A blood group has 'A' markers, B blood group has 'B' markers and O blood group has no markers. I dont know what the original group was though.

People cannot get blood transfusions from those with different blood groups because their own blood will attack it as it recognises it as foreign. The exception is O blood group which can safely be transferred into those with A or B blood type as it has no 'markers' so is not recognised as foreign.

Answer 5

The body rejects the blood, which causes organ failure? Correct me if I'm wrong?