Multiple alleles or polyaelia. Know cases of polyaelia

When studying genetics we observe two qualities of allele genes. In albinism, the THE determines normal skin, and its allele Thedetermines an anomaly. In peas, the R determines seeds with a smooth surface, while the r determines seeds with a rough surface. As for the fur of guinea pigs, the Ldetermines by the goose bumps, while the there determines by smooth, and so on.

We know that genes are pieces of DNA, and that diploid organisms will always have two alleles of each gene, one from the father and one from the mother. Thus, certain genes can mutate over time, giving rise to several allele genes. For example, if a gene THE if it duplicates, it will give rise to two genes THE identical to it. If these genes THE also if they duplicate, they will also produce genes THE identical. But if there is a mutation in this gene THE, it will change, so it can be called The. This modified gene will produce a different protein, perhaps because only one amino acid has been changed. the gene THE and the gene

The they can undergo one, two, three or several mutations, giving rise to a series of multiple alleles that control the same character. Thus, we can say that multiple alleles originate from preexisting gene mutations. This phenomenon can also be called polyaelia.

In the diagram above we can clearly see the origin of the multiple alleles.

To better understand polyaelia, we will cite the coat color of rabbits, which is a classic example of multiple alleles.

O gene Ç determines the coat color to be greyish-brown (wild or sharp). O gene ç^tea determines the coat color to be silver-gray (chinchilla). O gene ç^Hdetermines white coat with dark ends (himalayan), and finally the geneç, which determines the white coat (albino). O gene Ç that conditions wild hair is dominant over the other three alleles, and the gene ç^tea, which conditions the chinchilla fur, although it is recessive regarding the gene Ç, is dominant over the gene ç^Hit's the geneç. O gene ç^H, for the Himalayan is recessive in relation to gene Ç andgene ç^tea, but dominant over the geneç. O geneç, that conditions the albino phenotype is recessive in relation to the three other types of genes.

Phenotype	Gene	dominance relationship	Possible genotypes
aguti or wild	Ç	dominates the other genes	CC or CC^tea or Cc^H or Cc
Chinchilla	Ç^tea	Dominates Himalayan and Albino	ç^teaç^tea or c^teaç^H or c^teaç
Himalayan	ç^H	dominates albino	ç^Hç^H or c^Hç
Albino	Ç	Recessive in relation to others	cc

 Polyaelia is much more common than you might think. For the eye color of the banana fly, there are multiple alleles that, when combined in pairs, give rise to various shades. In vegetables, it is also common to see the phenomenon of polyaelia, especially in self-sterility, which does not allow for self-fertilization or fertilization of individuals with a very similar genetic pattern. For example, in tobacco the pollen grain has the S allele.₁, which prevents the growth in the carpels of flowers carrying the same gene. Thus, this pollen grain will only fertilize if the carpel is S₂s₃, S₃s₄, etc.

O ABO system of blood groups is a classic example of polyaelia in the human species.

By Paula Louredo
Graduated in Biology

Source: Brazil School - https://brasilescola.uol.com.br/biologia/alelos-multiplos-ou-polialelia.htm