How the blood groups A+ve, O+ve, AB+ve  are formed? In what way they are important. Is there any special functions for different blood groups.People of different blood groups. Why blood is...

How the blood groups A+ve, O+ve, AB+ve  are formed? In what way they are important. Is there any special functions for different blood groups.

People of different blood groups. Why blood is classiffied in to groups.  Is such classification is necessary.  Is each classification had any impact over the growth of human beings. Please clarify

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trophyhunter1 eNotes educator| Certified Educator

The type of blood you are born with is due to heredity based on the gene pair you receive from your parents for blood type. Blood type is actually what type of antigen, or protein is found on your red blood cells. There are four types of blood A, B, AB and O. The allele for A is codominant to the allele for B and both are dominant to type O. Following the Law of Dominance, if a person receives two genes for A they would be homozygous(pure) for type A. If a person receives one gene for A and one for O, they would be heterozygous for type A, since A is dominant to O, O will not be expressed in the phenotype, but remain hidden. If a person receives two B genes, they are homozygous for type B and if they receive one B gene and one O gene, they are heterozygous for type B, as the gene for B is dominant to O. If someone receives a gene for A and a gene for B, since these are co-dominant, both are expressed in the phenotype and the person is type AB. Finally, the only way a person can inherit the recessive type O blood, is by having two O genes(homozygous). Besides blood groups A,B, AB, O, another trait that is inherited is whether your blood is Rh+ or Rh-. This is another important antigen in the blood. In this case, Rh+ gene is dominant to Rh-. Therefore, an individual with two Rh+ genes are positive. A person with an Rh+ and an Rh- gene will be heterozygous but positive. And finally, a person would have to have two Rh- genes for the recessive trait to be expressed. The significance of these blood groups is that during a transfusion, the blood must be tested because giving someone an antigen they don't have, acts as a foreign protein and triggers an immune response. This causes clumping between the person's antibodies and the foreign blood and can be deadly. Therefore, a person with A can receive A or O, because O contains no antigens. B can receive B or O, AB can receive any blood type, as both antigens are present in their blood and O can only receive type O because A and B both contain antigens that would trigger an immune response in type O people. With the Rh factor, people who are Rh+ have the Rh antigen but people who are Rh- do not. Therefore, a person who is + can receive + or - blood without a problem. However, if someone is Rh-, they do not have the Rh antigen. If they are given Rh+ blood, it will trigger an immune response and they will build up antibodies. This is especially significant if a pregnant female is Rh- and the fetus, Rh+. The first pregnancy should be no problem, but, after labor, the mother's immune response will be activated. By the second pregnancy, her antibodies will attack another Rh+ fetus. If testing indicated this situation was present, the mother can be given drugs to suppress the formation of antibodies against the fetus.