Lacking any scientific merit, racial segregation of blood remained the policy of the American Red Cross until 1950, despite the protestations of a prominent African American physician and transfusion researcher, Dr. Therefore, a person may have a Rh + blood type and can still have an Rh - gene (See the chart below. the Rh negative (Rh-) gene is also masked by the presence of a Rh positive (Rh+) genotype. Rh Positive (Rh+) and Negative (Rh-) Blood Types. Isolation of small populations, which led to genetic drift. If one parent has A and another has O, they can either produce a child with A or O blood types.
Racial Differences: Differences in the frequency of blood types inĭifferent populations of humans are presumably due to historical In an emergency, where there isn't time to do a blood type test, knowing who is a universal donor could save lives. Since the plasma (the liquid part of the blood, from which the red and white cells have been removed by centrifuging) of Type AB positive people contains no antibodies, the plasma of Type AB positive donors is universal. Seen as foreign so Type AB positive is the universal recipient. Because red blood cells of Type AB positive have all possible antigens (proteins), none will be ABO Typeĭonors and Recipients: Because the red blood cells of blood Type O negative people contain no proteins thatĬould be rejected, Type O negative is referred to as the universalĭonor. Finally, genotype AB allows both alleles A and B to. Future pregnancies can be increasingly difficult, as the mother's antibodies attack the baby. Genotype oo produces neither A nor B antigens, which results in the O blood type ( universal donor ). (The baby of an Rh positive father and an Rh negative mother can be +/- or -/-.) If the baby is +/-, the first pregnancy causes Rh sensitization in the mother, because she is exposed to foreign proteins and builds up antibodies against them. Rh Sensitization: One interesting medical scenario involves an Rh negative mother who carries an Rh positive baby. People who are -/- do not posess the Rh(D) antigen and test as Rh negative. People who are +/+ or +/- possess the Rh(D) antigen and test as Rh positive. Genotypes for the Rh factor are +/+, +/-, and -/. The Rh factor is inherited independently from the ABO blood type. Rh Factor: The Rh factor, the second most important blood group system after the ABO blood group system, was first discovered in rhesis monkeys. The body produces antibodies that will attack any foreign type. *Type AB is rare and was discovered later.ĪBO Blood Type: An individual's red blood cells will contain proteins of type A, or B, or both, or neither. The specific combination of these four components determines an individuals type in most cases.
There are two antigens and two antibodies that are mostly responsible for the ABO types. There are four principal types: A, B, AB, and O.
In 1901, it was discovered that there were three* blood types, A, B, and O, and that mixing blood from different types caused an immune response that resulted in clumping. All humans and many other primates can be typed for the ABO blood group. Blood Type Genetics ABO and Rh Blood Types inĮarly experiments with human blood transfusion often resulted in the death of the patient for unknown reasons.
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