4.b.2.c) Dominant and recessive genes

The example with the brakes in the evolution of is very interesting because it makes one reflect on the real nature, and the instrumental behavior, of dominant or recessive genes included in genetic code.

Regarding the molecular mechanism in which dominant genes function, we must first ask ourselves whether the character of dominant or recessive genes is clearly understood, or whether we are talking about an old-fashioned and rather basic concept which should be further defined based on, for example, its function within the framework of genetic evolution.

With reference to the examples used to explain the Mendelian genetics, I have always wondered which of the genes would express if both genes of both parents were dominant genes or if both were recessive genes.

Example in the technological evolution
Gene expression and significativity

We should bear in mind that the concept of dominant gene implies a certain amount of discrimination against the character that is forming in the new being. We must therefore examine the possible causes of this discrimination, which will finally lead to a better, faster, or safer evolution.

Let us consider the next example about the Mendelian significance of dominant and recessive character. To make it easier to understand, I have used mechanics in evolution of cars as an analogy:

  • Two types of genes exist for the particular characteristic of our car: gene type B and gene type B+A

  • Gene type B contains the technical specifications for the car's basic brakes

  • Gene type B+A (as well as the car's basic brakes) also incorporates the technical specifications for ABS brakes (hereinafter referred to as ABS t.s.)

The possible Mendelian combinations of the two types of genes would be the following concerning the significance and genetic expression of the genes:

  1. The dominant genes are the less evolved ones.

    Let us assume that in the event of faulty ABS t.s. brakes, neither of the brake systems would work (not even the basic) - this is case 1. It is obviously imperative to guarantee the commercial reliability of the new car (including the avoidance of accidents) that the brakes must always work (either the basic or the basic + ABS).

    Thus, when installing ABS brakes, one must be absolutely convinced that the technical specifications are correct. Only comparing the technical specifications in both genes can only ensure this. If they coincide, we can be sure that practically no fault exists, as it would be difficult for them to coincide in one particular fault.

    If one of the genes does not include ABS t.s. or if ABS t.s. is included in both genes, but is not identical in both the result will be a lack of ABS brakes. Therefore, in case 1 the dominant gene is type B because its presence forces normal brakes to develop; as it is impossible, as previously stated, for the ABS t.s. to coincide in both genes.

    Note that gene type B is the least evolved of the two in our example.

  2. The dominant genes are the modern ones.

    Now let us consider the opposite case (case 2) - that in the event of faulty ABS t.s., the ABS brakes cease to function but the basic brakes are not affected. This means that to guarantee the commercial reliability of the new vehicle the presence of ABS t.s. is not essential in both genes, as any fault would not harm the basic brakes or the car.

    Consequently, if only one B+A gene type exists, the car would be manufactured with ABS brakes, as if they are operational, it is only an advantage and poses no risk.

    In this last case, the dominant genes are type B+A; because it is present, it will always manifest itself and it is still more evolved (modern) than type B. As we can see, the dominant genes from the first case have become recessive genes and the recessive genes have become dominant genes. This implies that a dominant or recessive character is a relative concept.

Now agree to add a new gene type - B+A+M. This gene type has more modern (powerful) technical specifications than ABS. In the example at case 1, we would find that gene type B+A would be a recessive gene compared with type B and a dominant gene compared with type B+A+M. On the other hand, for case 2, gene type B+A would be a dominant gene compared with type B and a recessive gene compared with type B+A+M.

In the genetic makeup of a new being, a genetic sign (mark) is necessary to establish the kind of behavior or character - in other words, a particular DNA chain is compulsory. An example of a molecular mechanism that allows the incorporation of this genetic mark would be histones (pieces of ADN) studied by modern molecular biology.

Now let us discuss whether the dominant genes compensate for the recessive genes or solely the dominant genes express. Here we faced the same dilemma - the answer is that it depends. In case 1, due to the dominant character of the gene type B the result is basic brakes and, if both genes are type B+A and no mistake is detected when verifying the technical specifications, the recessive character of gene type B+A could develop both basic and ABS brakes.

In case 2, the dominant character of gene type B+A develops both types of brakes and the recessive character of gene type B, only basic brakes. Either way, I assume that nature has come across all types of cases (similar to, and different from cases 1 and 2).

All of the above is in fact a very simplistic explanation, although not as simplistic perhaps as the old-fashioned concept of the dominant gene or recessive gene. And much less simplistic than co-dominant and co-recessive,  which continue without giving any kind of argument about why genes are dominant or recessive under different conditions.

Do not forget that nowadays the generally accepted school of thought is that the evolutionary process depends on a combination of random mechanisms and natural selection. In my opinion, this line of thinking could apply to the evolution of insects, bearing in mind that millions and millions of baby insects are born in short periods; but although they have been evolving for millions of years, their evolution has not been particularly great.


The discovery of various pieces of ochre carved with geometric motifs in a South African cave over the Indian Ocean leads us to believe that modern human behavior originated at least 77,000 years ago during the African Stone Age.

Examples of the oldest artistic activity known until now, the cave paintings in Spain and France, were much more modern but also more convincing.

El País 11-01-2002. Science / Journal of Human Evolution

In fact, the evolution of man has just been the opposite. There have been only 2000 generations of human descendants (if one accepts that modern humans have only existed for 40000 or 50000 years); although few children are born per generation, the evolution of the human brain has been enormous.

How many combinations of direct descendants would be necessary for the Windows 3.11 code to evolve into the Windows 95 code using an evolutionary process based on random mutations?

How many combinations would be necessary for the technical specifications of basic car brakes to convert into ABS brakes in the evolution of cars?

I believe that we should change our philosophical ideas surrounding genetics and evolution. This minor change would lead to recognition of the intrinsic dynamics of genetic evolution of vital impulse systems.