What is the Difference Between Allele and Genotype?

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The difference between an allele and a genotype lies in their definitions and roles in genetics:

  • Allele: An allele is a variation or alternative form of a gene. Different alleles can exist for the same gene, and they typically differ in their nucleotide base sequence at a specific genome location or loci. Any given gene can have multiple alleles, and each individual inherits two alleles for each gene, one from each parent.
  • Genotype: An individual's genotype refers to the unique combination of alleles they possess for a particular gene. For example, if a gene has two alleles, A and B, an individual's genotype could be AA, AAB, AAA, or BBB, depending on which alleles they inherited from their parents. The genotype determines an organism's traits or characteristics.

In summary, alleles are different versions of a gene, while a genotype is the specific combination of alleles an individual possesses for a particular gene. Both alleles and genotypes play crucial roles in determining an organism's traits and characteristics.

Comparative Table: Allele vs Genotype

Here is a table comparing alleles and genotypes:

Feature Allele Genotype
Definition A DNA sequence at a specific chromosomal location, which presents as a variant or alternative form of a gene. The combination of alleles that an organism has.
Role Alleles contribute to the diversity in phenotype expression. Determines an organism's phenotype.
Inheritance Humans inherit two alleles at any given locus, one from each parent. An individual's genotype is determined by their unique combination of alleles.
Number per locus Alleles are found in pairs. The genotype is the entire set of alleles for an organism.
Examples Blue eyes, brown eyes, blond hair, red hair, blood types. Eye color, hair color, skin pigmentation, blood types.

In summary, an allele is a variant form of a gene, and it determines an organism's genotype. On the other hand, a genotype is the combination of alleles that an organism possesses, and it determines the organism's phenotype.