Why humans have different blood types?

Answer 1

The blood groups are named for the presence of different glycoproteins sitting on the outside of the red blood cell. There are antibodies floating in the blood which attack the other blood groups, not your own.

You inherit one blood group gene from each of your parents. These are named "A" or "B". If you get a different one from each parent, you are type AB. If neither is present, you are called type O.

Answer 2

It will be down to genetic mutation. There are some theories that according to where your ancestors originated from, that is how your blood type will be determined. Native peoples such as the American Indians, Australian Aboriginals and some African peoples tend to have an O blood type which was apparently the first hunter and these people thrived on meat. If your ancestry is European then you'd most likely by an A blood type which were the first hunter-gatherers that ate a mainly vegetarian diet with lots of nut and cereals. The Asian peoples are supposed to most commonly have a B blood type and they are a combination of both. Not sure how that theory works when multiculturalism is factored into it though.

Answer 3

For the same reason that they have different skin colours, hair & eye colours etc - mutation has caused genetic variation. There are many different blood groups, of which the most (?) important are A, B, O. These are due to antigens on the red blood cells. There are three forms of these antigens - A,B, and O. People either have A, B, O or both A & B - giving the groups A, B, O and AB. The different antigens are produced by a gene now called "I" which exists in three forms (alleles). If you give a patient the wrong blood group, the blood cells will clump together (agglutinate) - and clumps of blood cells in the blood vessels won't do the patient any good at all! For a planned transfusion, other blood groups will have to be considered, not just A,B,O.

Answer 4

we all come from different backgrounds, race, nationalities.. that would be like asking why we all have different hair or eye color...or why our skin tones are different...There are different blood type groups, many of us with different race, nationality etc have the same blood type. There needs to be differences among us in order for us to be considered different, and human. If we were all made the same, we wouldn't be human would we? we would be more like clones.

Answer 5

A total of 29 human blood group systems are recognized by the International Society of Blood Transfusion (ISBT).[1] Each blood group is represented by a substance on the surface of red blood cells (RBCs). These substances are important because they contain specific sequences of amino acid and carbohydrate which are antigenic. As well as being on the surface of RBCs, some of these antigens are also present on the cells of other tissues. A complete blood type describes the set of 29 substances on the surface of RBCs, and an individual's blood type is one of the many possible combinations of blood group antigens; usually only the ABO blood group system and the presence or absence of the Rhesus D antigen (also known as the Rhesus factor) are determined and used to describe the blood type. Over 400 different blood group antigens have been found, many of these being very rare.[citation needed] If an individual is exposed to a blood group antigen that is not recognised as self, the individual can become sensitized to that antigen; the immune system makes specific antibodies which binds specifically to a particular blood group antigen and an immunological memory against that particular antigen is formed. These antibodies can bind to antigens on the surface of transfused red blood cells (or other tissue cells) often leading to destruction of the cells by recruitment of other components of the immune system. Knowledge of an individual's blood type is important to identify appropriate blood for transfusion or tissue for organ transplantation.

Answer 6

Each blood group has a special anti-body (they are the hormones that are secrete in the blood).Every person has a different anti-body therefore each person have different blood group. Some people have the same blood group even if the are not related in any manner. In this case they have the same type of anti-body, therefore they have same blood group.

Answer 7

Each and every human has a unique blood type. Some people have similarities so scientists have made groups and subgroups of them, but our blood is as unique as our finger prints or as our retinas. Just because we all have eyes and legs and ears and noses, it doesn't mean we are the same. We are all unique individuals.

Answer 8

I have a diet/food program book that actually delves into this. It's fascinating. It has to do with the availability of food from the dawn of man through about the 10th century AD:

Type O - O is for OLD
Cro-Magnon ancestors appear around 40,000 BC and become the top of the food chain. They hunt in organized packs, learn to make weapons and use tools. Soon they have no natural predators and the population explodes. Type O is the predominant blood type (then and now).

Diet is heavily protein, and it does not take long for them to kill off the big game. More people to feed, more competition for meat. Hunters begin fighting and killing others who encroach on their hunting grounds. With the loss of good hunting grounds, the migration of the human race begins.

Type A - A is for Agrarian
This type appears somewhere in Asia or Middle easte between 25,000 and 15,000 BC in response to new environmental conditions. Agriculture and animal domestication are strong in this culture. Cultivation of grains and stock allow populations to establish communities and permanent living structures. The resulting changes in diet and environment lead to a mutatinn in the digetstive tracts and immune systems, allowing them to better tolerate cultivated grains and other agricultural products. Type A is born and quickly becomes more resistant to infections that are common to dense populations.

The gene for Type A spreads beyond Asian and Mid-East, into western Europe. In time the digestive systems of the hunter-gatherers loses its ability to digest the carnivorous diet.

Type B - B is for Balance
Type B developed between 15,000 and 10,000 BC in the area of the Himalayan highlands (present day Pakistan and India). The population was pushed from the hot African savannah to the cold of the Himalayas and so Type B may have developed in response to climate changes. Mongolians move northward, culture of herding and domesticating animals. Two type B populations are established: agrarians and nomadic.

Type AB - AB is for Modern
AB is rare, and developed through the intermingling of Type A caucasians with Type B mongolians. It's found in less than 5% of the population and is the newest of the blood types. Until 10-12 centuries ago (1000 to 1200 years ago), there was no Type AB. Type AB is rarely found in European graves prior to AD900.


The above information comes from a book titled "Eat Right 4 Your Type" and is a diet program based on an individual's blood typing. It identifies foods you will digest better based on the chemistry of your blood. Through this book I learned why I can eat turkey but not chicken, apples but not bananas, etc.

(and I'm type AB by the way...)

Answer 9

Don't have the medical explanation,just a theoretical,maybe from our ancestors eating different types of foods eventually changed the makeup of our blood giving us a certain type when mixed together in different humans.How's that.

Answer 10

Mutations, survival of human kind