The Bombay phenomenon is what?

The human body is famous for its uniqueness. Due to various mutations that occur daily in our body, we become individual, as some of the signs that we acquire are significantly different from those of other people's external and internal factors. This refers to blood groups.

Usually it is customary to subdivide it into 4 types. However, it is extremely rare, but it occurs that a person who must have one blood group (due to the genetic characteristics of the parents) has a completely different, specific. A similar paradox is called the "Bombay phenomenon."

What it is?

By this term we mean a hereditary mutation. It is extremely rare - up to 1 case per ten million people. The Bombay phenomenon got its name from the Indian city of Bombay.

In India, there is one settlement, in people who are quite often found "chimera" blood type. This means that in determining the erythrocyte antigens by standard methods, the result shows, for example, the second group, although in fact due to the mutation in humans is the first.

This is due to the formation of a recessive pair of H. genes in humans. Normally, if a person is a heterozygote for a given gene, then the symptom does not appear, the recessive allele can not fulfill its function. Due to an incorrect combination of parental chromosomes, a recessive pair of genes is formed, and the Bombay phenomenon takes place.

How does it develop?

History of the phenomenon

A similar phenomenon has been described in many medical publications, but practically up to the middle of the 20th century no one had an idea of why this is happening.

This paradox was discovered in India in 1952. The doctor, carrying out the research, noticed that the parents had only blood groups (the father had the first and the mother had the second), and the born child had a third.

Interested in this phenomenon, the doctor was able to determine that the body of the father was able to somehow change, which made it possible to believe that he had the first group. The very modification occurred due to the lack of an enzyme, which makes it possible to synthesize the desired protein, which would help determine the necessary antigen. However, if there was no enzyme, then the group could not be determined correctly.

The phenomenon in the representatives of the Caucasoid race is quite rare. Somewhat more often it is possible to find carriers of "Bombay blood" in India.

Theories of the origin of Bombay blood

One of the main theories of the appearance of a unique blood group is the chromosomal mutation. For example, in a person with a fourth blood group, recombination of alleles on chromosomes is possible. That is, in the formation of gametes, the genes responsible for the inheritance of the blood group can move as follows: the genes A and B are in the same gamete (the subsequent individual can receive any group except the first), and the other gamete will not carry the genes responsible for the blood group . In this case, it is possible to inherit gametes without antigens.

The only obstacle to its spread is that many such gametes die without even embryogenesis. However, perhaps some survive, which subsequently promotes the formation of Bombay blood.

It is also possible to disrupt the gene distribution at the zygote or embryo stage (as a result of a maternal eating disorder or excessive alcohol use).

The mechanism of development of this state

As it was said, everything depends on genes.

The human genotype (the totality of all its genes) directly depends on the parent, or rather, on what signs passed from parents to children.

If you study the composition of antigens more deeply, you can notice that the blood group is inherited from both parents. For example, if one of them has the first and the other has a second child, then the child will have only one of these groups. If a Bombay phenomenon develops, everything happens a little differently:

• The second blood group is controlled by the gene a, responsible for the synthesis of a special antigen - A. The first, or zero, does not have specific genes.
• Synthesis of antigen A is due to the action of the site of the chromosome H, which is responsible for differentiation.
• If there is a malfunction in the system of this part of the DNA, then the antigens can not properly differentiate, because of what the child can get from the parent antigen A, and the second in the genotype pair the allele can not be determined (conditionally it is called nn). This recessive couple suppresses the action of site A, as a result of which the child has the first group.

If we generalize everything, then it turns out that the main process that causes the Bombay phenomenon is a recessive epistasis.

Non-allelic interaction

As it was said, the basis for the development of the Bombay phenomenon is the non-allelic interaction of genes-epistasis. This type of inheritance is distinguished by the fact that one gene suppresses the action of another, even if the suppressed allele is dominant.

The genetic basis of the fact that the Bombay phenomenon is developing is epistasis. The peculiarity of this type of inheritance is that the recessive epistatic gene is stronger than that of a hypostatic gene, but it determines the blood group. Therefore, the inhibitor gene, which causes suppression, is not capable of forming any trait. Because of this, a child with a "no" blood group is born.

Such interaction is genetically conditioned, so it is possible to identify the presence of a recessive allele in one of the parents. Affect the development of this group of blood, much less change it is impossible. Therefore, those who have a Bombay phenomenon, the daily routine dictates some rules, observing which, such people will be able to live normally and not be afraid for their health.

Features of life of people with this mutation

In general, people who carry bombshell blood are no different from ordinary people. However, problems occur when a transfusion is required (a serious operation, an accident or a blood system disease). Due to the specific antigenic composition of these people, they can not be transfused with other blood, except bombs. Especially often such errors occur in extreme situations, when there is no time to thoroughly study the analysis of red blood cells of the patient.

The test will show, for example, the second group. If the blood of this group is transfused to the patient, intravascular hemolysis may develop, leading to a fatal outcome. It is because of this incompatibility of antigens that the patient needs only Bombay blood, necessarily with the same rhesus as his.

Such people are forced from the age of 18 to conserve their own blood, so that later it should be poured in case of need. There are no other features in the body of these people. Thus, it can be said that the Bombay phenomenon is a "way of life", and not a disease. You can live with it, only you should remember about your "uniqueness".

Problems with paternity

The Bombay phenomenon is a "thunderstorm of marriage". The main problem is that in determining paternity without special studies it is impossible to prove the existence of a phenomenon.

If someone suddenly decided to clarify the relationship, then he should certainly inform him that it is possible that such a mutation exists. The test for genetic coincidence in this case should be carried out more broadly, with the study of the antigenic composition of the blood and red blood cells. Otherwise, the mother of the child runs the risk of being left alone, without her husband.

This phenomenon can only be proved with the help of genetic tests and determining the type of inheritance of the blood group. The study is rather expensive and not currently widely used. Therefore, the birth of a child with a different blood group should immediately suspect the Bombay phenomenon. The task is not easy, since dozens of people know about it.

Bombay blood and its current occurrence

As has been said, people with Bombay blood are infrequent. In representatives of the Caucasoid race, this type of blood is practically not found; In Hindus, this blood is more common (on average, the Europeans have the occurrence of this blood - one case per 10 million people). There is a theory that this phenomenon develops due to the national and religious characteristics of the Hindus.

Everyone knows that in India a cow is a sacred animal and its meat can not be eaten. Perhaps because beef contains some antigens capable of causing a change in the genetic code, Bombay blood is more often manifested. Many Europeans eat beef meat, which serves as a prerequisite for the emergence of the theory of antigenic suppression of the recessive epistatic gene.

Perhaps, the climatic conditions also influence, however this theory is not currently being studied, therefore there is no evidence for its justification.

The Importance of Bombay Blood

Unfortunately, few people have heard about Bombay blood now. This phenomenon is known only to hematologists and scientists working in the field of genetic engineering. Only they know about the Bombay phenomenon, what it is, how it manifests itself and what needs to be done when it is revealed. However, the exact cause of this phenomenon has not yet been revealed.

If viewed from the point of view of evolution, then Bombay blood is an unfavorable factor. Many people sometimes require transfusion or substitution for survival. In the presence of Bombay blood, the difficulty lies in the impossibility of replacing it with blood of another type. Because of this, lethal outcomes often develop in such people.

If you look at the problem from the other side, then it is possible that Bombay blood is more perfect than blood with a standard antigenic composition. Its properties are not fully understood, therefore it is impossible to say what the Bombay phenomenon is - a curse or a gift.