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What is Alleles?

Meaning and Definition of Alleles

Alleles are the alternate forms of a gene and occupy the same place on homologous chromosomes. When we refer to locus, we are talking about the position of the gene on the chromosome . When we talk about homologous chromosomes, we mean chromosomes that have genes for the same characteristic.

Alleles are one of several forms of a certain gene, occupying a position on a certain chromosome , known as the locus .

There are organisms that are diploid , that is, they have pairs of homologous chromosomes in their somatic cells, where two copies of the same gene are present. In this way, beings that have two identical copies of a given gene are called homozygotes and beings that have different alleles are called heterozygotes.

However, there are exceptions to the way a heterozygote expresses itself phenotypically. An example is incomplete dominance, which occurs when alleles mix their characteristics in the phenotype. A second example is codominance, when alleles are expressed simultaneously.

There are also multiple alleles or polyallelia , which is a series made up of three or more alleles, belonging to the same gene, which occur in pairs, but with various possible combinations.

Multiple alleles are the result of successive mutations in genes at a given locus. Each mutant gene that appears establishes a condition for the appearance of another new phenotypic expression of that character in particular, in that species.

Alleles are the alternate forms of a gene and occupy the same place on homologous chromosomes. When we refer to locus, we are talking about the position of the gene on the chromosome . When we talk about homologous chromosomes, we mean chromosomes that have genes for the same characteristic.

Alleles are one of several forms of a certain gene, occupying a position on a certain chromosome , known as the locus .

There are organisms that are diploid , that is, they have pairs of homologous chromosomes in their somatic cells, where two copies of the same gene are present. In this way, beings that have two identical copies of a given gene are called homozygotes and beings that have different alleles are called heterozygotes.

However, there are exceptions to the way a heterozygote expresses itself phenotypically. An example is incomplete dominance, which occurs when alleles mix their characteristics in the phenotype. A second example is codominance, when alleles are expressed simultaneously.

There are also multiple alleles or polyallelia , which is a series made up of three or more alleles, belonging to the same gene, which occur in pairs, but with various possible combinations.

Multiple alleles are the result of successive mutations in genes at a given locus. Each mutant gene that appears establishes a condition for the appearance of another new phenotypic expression of that character in particular, in that species.

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