Knowledge of variation has wide application in human life and these include blood transfusion in medicine;crime detection; determination of paternity; classification of human race and agriculture.
For the blood transfusion to be successful,it is necessary to ensure that the blood from the donor is suitable and compatible with that of the recipient.If not,there would be agglutination of the red blood cells and antibodies of the blood plasma.An antigen is any foreign and potentially dangerous substance in the blood. Antigens stimulate an animal to form antibodies.Antibodies are large protein molecules contained in the blood plasma,which form part of the immune system and function to fight diseases in the body
When an antibody comes in contact with an antigen,the two bond together and this will attract the attention of white blood count clearly which move in to destroy the invading antigens Certain antigens however,occur naturally in the blood and are not harmful by themselves.These antigens which are called type A,B and Rh antigens are found in the cell membrane of Red blood cells.Blood containing type A antigen is called Type A blood.If the blood contains type B antigen,it is called type B blood.Type AB blood contains type A and B antigens.Blood that does not contain either antigens is called type O.
Crime detection-Morphological features which are peculiar to individuals can be used by the police and detectives to trace criminals.Such features include height,skin color,color of eyes,color of hair,marks on the body or face and fingerprint.
Physiological features such as rolling of tongues and difference in blood group are also used.Fingerprints serve as man's signature and also helps in crime detection when found in the scene of the crime.