What are alleles?

Alleles are defined as different versions of a gene that occupy the same position, or locus, on homologous chromosomes. For any given gene, an individual may inherit one allele from each parent. These variations can lead to differences in traits, such as flower color in plants or blood type in humans. This diversity is crucial for the process of evolution as it contributes to genetic variation within a population.

Identical copies of a gene do not account for the variability present in alleles, as they would represent a single allele rather than multiple versions. Dissimilar genes located on the same chromosome mischaracterize alleles, as alleles refer specifically to variations of a single gene, not different genes overall. Mutated genes that cause illness also do not represent alleles accurately; while they might be alleles, not all alleles are mutations, and many are simply normal variants leading to different phenotypes. Therefore, the definition of alleles as different versions of a gene is essential for understanding genetic diversity and inheritance.