Why does your child have black hair, when you're blonde?

It is well known that genes transfer from one to other generation, together with phenotypic traits. Genes consist of alleles. Every allele has specific phenotype information. 

Dominant and recessive traits are part of the so called inter-allelic interaction. This kind of interaction appears as a result of interplay between the alleles in one single gene and their manifestation in different forms. Some alleles that are parts from one particular gene are nominated as dominant alleles, and they can be expressed when are contained in karyotype. For example, if the father has black hair, and the mother is blonde, then the dominant traits attack and the baby has black hair. But here present are the recessive traits too, and they can be expressed even after few generations of black hair. Then the baby might be blonde.

As we said, besides dominant, recessive alleles also exist, and they can be expressed only when the dominant are absent. This happens quite rarely and it depends on the hybridisation. That is when the nuclear cells bond. Recessive traits make appearance when the dominants gene alleles mutate, which causes change in some kind of protein synthesis. Then the recessive traits pass on the next generation. And they can continue passing by on the new generations, but the number is shrinking unless it can be combined again with more recessive traits.

During fertilization, the recessive traits express themselves only if there are dominant traits in the other karyotype. The recessive trait wants to rule only if they are in charge, other wise the dominant will be, of course, the dominant traits. We can come to a conclusion that the dominant trait appear in homozygous and heterozygous form, and the recessive ones appear strictly in homozygous form (and only when the two parents contain just the recessive traits).

The inheritance of plenty phenotypes are defined only by one gene - when there's inter-allelic interaction , dominants and recessive. 

I hope you liked it. For more interesting posts, stay tuned!