In genetics, the term allele refers to different versions of a gene that occur at a specific locus on a chromosome. Each individual inherits two alleles for each gene, one from each parent. Alleles can be dominant or recessive, influencing the expression of traits. For instance, a dominant allele will mask the effect of a recessive allele in a heterozygous genotype. This genetic variation contributes to the diversity of traits observed in populations and is fundamental to the study of inheritance patterns.