Blood types arose for protection against viruses

As scientists from University of Bath believe, the person could get the enzymes defining a blood type, at bacteria – they were necessary to interfere with distribution of viruses to populations. Erythrocytes in blood of the person are covered with carbohydrate structures which call gliko-anti-genes. The phenotype of these anti-genes determines a blood type by AB0 system. A-positive people have the antibodies resisting to gliko-anti-genes of group B, B-positive have anti-And and anti-0, 0-positive – anti-A and anti-B. These antibodies don't exist at the beginning of organism formation, and appear with intestinal bacteria which make eritrotsitarny anti-genes. Viruses in a cover bear part of a membrane of a cage owner which contains anti-genes of blood types. As a result, if the virus arrives from an A-positive organism in B-or 0-positive, the immune system kills him etc.

Gliko-antigena consist of groups of enzymes – гликозилтрансфераз. Scientists investigated three-dimensional structure of a molecule гликозилтрансферазы from an intestinal bacterium of Bacteroides ovatus. It appeared that it has the structure similar with maternal, though possesses functional differences (its working capacity doesn't depend on ions). They show that maternal enzyme could occur from bacterial as a result of a horizontal transfer of genes (passing a specific barrier), instead of by vertical (from generation to generation). It is supposed that genes of bacterial enzyme were introduced in an organism of the ancestor of modern vertebrata, and from them there was an enzyme of the person as a security measure from viruses. Article with this conclusion is published by scientists in the Scientific Reports magazine.