The various forms of the DNA segments that we analyzed consist of three so-called single-nucleotide polymorphisms (SNPs). That means that replacing just a single building block of DNA (a basis) can cause a genetic mutation. Due to the new combination, the amino acids that are built into the protein change and, consequently, the structure of the receptor is changed. This is how mutations have an effect on taste perception.

The three SNPs of the genes TAS2R38: on amino acid position 49 of the receptor protein alanine can be replaced with proline. This happens, when on the DNA in this position the base guanine is replaced with cytosine. These are often abbreviated as Ala49Pro or A49P, when one views it from the (receptor) protein side. On the gene the base triplet changed from GCA to CCA. On amino acid position 262, valine can be replaced with alanine (Val262Ala; GTT to GCT) and on position 296, isoleucine with valine (Ile296Val; ATC to GTC).

Insofar as the variations to the genotype can occur independently from one another, the result is eight different combination possibilities for this gene, of which the types PAV and AVI most commonly appear in Europe. For a diploid set of chromosomes for a person - we receive a chromosome set from our father and from our mother - possible combinations are PAV/PAV, AVI/AVI, and PAV/AVI.

According to scientific literature, the type PAV/PAV is the wild type and labels supertasters concerning PROP as well as PTC. This means that the genetic combination has been causing people especially sensitive to bitter substances to react since the primeval times. Our ancestors were protected from consuming poisonous plants.

The combination AVI/AVI refers to the so-called non-tasters. These people cannot taste bitter substances as well as people of the PAV/PAV type. The AVI/AVI type caught on later for evolutionary reasons, when the perception of taste for protection from poisonous plants lost importance thanks to agriculture and collective knowledge about nature.

The type PAV/AVI is a mixed form. Due to its sensitive taste receptor, the PAV/AVI form can taste bitter substances better than non-tasters, but is not as sensitive as supertasters.

It can be pointed out, that the terms “supertaster” and “non-taster” are rather avoided in the new literature. Today, one is convinced that this categorization is tricky because taste perception is based on a number of relevant genes which are easy to miss.