Allele genes are those that occupy the same locus on homologous chromosomes and are involved in the determination of the same character.
Allele genes may or may not determine the same aspect. An example is that a person may have a gene that determines the color of brown eyes and another gene that determines the color blue. In this case, they are allele genes, acting on the same character, but not determining the same condition.
Allele genes occur in pairs. One comes from the mother and the other from the father.
Concepts involved with Allele Genes
Although they are located in the same locus and act to determine the same character, the allele genes are not necessarily identical.
Thus, they can be classified into homozygotes and heterozygotes.
- Homozygous Allele Genes: When the alleles for a given trait are the same. Example: AA, aa.
- Heterozygous Allele Genes: When the alleles for a particular trait are different. Example: Aa.
Based on homozygotes and heterozygotes, another classification emerges in dominant and recessive.
Dominant Allele Genes: The presence of a single dominant allele is sufficient for the manifestation of a certain characteristic, which can occur in homozygous or heterozygotes. Dominant alleles are represented by capital letters. Example: AA or Aa.
Recessive Allele Genes: The manifestation of a certain characteristic only occurs in homozygotes. Recessive alleles are represented by lowercase letters. Example: yy.
Allele Gene Representation
Learn more about related topics:
- chromosomes
- homologous chromosomes
- Introduction to Genetics
