Antigens are molecules that the immune system can recognize and, if necessary, destroy. A B antigen is a molecule that can be used to categorize different types of red blood cells. There are four blood groups: A, B, AB, and O, and each person belongs to one of them. Because different blood groups can interact negatively with one another, it is necessary to determine a person’s blood type before administering a transfusion.
Blood groups are inherited genetically, which means that a baby inherits one blood group gene from his or her mother and another from his or her father. A B antigen cell gene from one parent can be inherited alongside a B antigen cell gene from the other. The baby will be of blood group B in this case. The baby will be blood group B if he or she inherits one B antigen gene and one O antigen gene. If a parent gives their child one B antigen and one A antigen, the child will be of blood group AB.
In most cases, human cells have a matching pair of 23 chromosomes. On chromosome 9, the blood type genes are located. Minor variations in the gene’s sequence result in different versions of molecules known as glycotransferases, which results in the presence or absence of antigens on the cell’s surface.
B antigen molecules protrude from the red blood cells of a type B child. People with blood group A have A antigens, while those with blood group AB have both A and B antigens. These antigens are absent in Type O people.
Antibodies to the A antigen circulate in the blood of type B people. Antibodies to A antigens are specific and stick to them. This causes the A blood cells to clump together, which can lead to serious medical problems.
These antibodies are not present in Type AB people. As a result, a person with blood type B can receive blood from people with blood types B or O, but not from people with blood types AB or A. Antibodies to other blood types develop even before a person receives a blood transfusion because bacteria and possibly plants produce similar antigens.
People with certain blood groups are more resistant to specific diseases than those with other blood types, which may explain the wide range of blood types. Over the course of evolutionary history, a beneficial mutation could have given one person an advantage in surviving disease. People with blood type O are more susceptible to cholera and plague than those with other blood types. People with type A blood are more susceptible to smallpox and some cancers than those with antigens O or B.
Apes and humans have some blood types in common. Baboons have blood types A, B, and O, whereas chimps almost always have A, rarely have O, and never have B. On the other hand, gorillas only have type B blood.