Allele

An allele is a term used in the field of genetics and biochemistry to describe alternative forms of a gene that occupy a specific position, or locus, on a chromosome. Genes are segments of DNA that code for specific traits or functions, and each gene can have multiple alleles.

Alleles arise through mutations or genetic variations in the DNA sequence. These variations can result in different versions of a gene, leading to differences in the traits or characteristics they control. Alleles can be classified as either dominant or recessive, depending on how they interact with each other.

When an individual inherits two identical alleles for a particular gene (e.g., two alleles coding for brown eyes), they are said to be homozygous for that gene. If they inherit two different alleles (e.g., one allele coding for brown eyes and another for blue eyes), they are said to be heterozygous.

The combination of alleles an individual possesses contributes to their genotype, which, in turn, influences their phenotype—the observable traits or characteristics. The study of alleles and their interactions is fundamental to understanding inheritance patterns and the diversity of traits within populations.