An allele is an alternative form or version of a gene.
Genes determine various traits, such as eye color, hair texture, and blood type. However, genes can exist in different forms, and these forms are called alleles. We inherit one allele for each gene from each parent. These pairs of alleles may be the same or different.
Here’s a breakdown of key concepts:
Understanding Alleles
- Alternative Forms: Alleles represent variations of a specific gene. Think of a gene like a recipe, and alleles as different versions of that recipe that might result in slightly different outputs.
- Inheritance: We inherit one allele for each gene from our biological mother and one from our biological father.
- Lumping into Categories: Alleles are usually categorized, and scientists study how these categories relate to traits.
Examples of Alleles
- Eye Color: A gene for eye color might have alleles for blue eyes, brown eyes, and green eyes.
- Blood Type: The gene for blood type has alleles for A, B, and O blood types.
How Alleles Work
The combination of alleles you have for a particular gene determines the specific trait that will be expressed. For example:
- Homozygous: If the two alleles you inherit are the same (e.g., two alleles for blue eyes), you are homozygous for that trait.
- Heterozygous: If the two alleles you inherit are different (e.g., one allele for blue eyes and one for brown eyes), you are heterozygous for that trait. The interaction between alleles in a heterozygous condition determines which trait is expressed.
In summary, an allele is one of the different forms a gene can take, and these different versions influence the traits we inherit.
