What is an allele?

An allele is defined as an alternative form of a gene that occupies the same position or locus on a homologous chromosome. Genes can have multiple variants, and these variations, or alleles, can dictate different traits or characteristics in an organism. For instance, a gene that determines flower color in a plant may have a blue allele and a red allele, leading to different colors in the flowers depending on which alleles are present.

This concept is fundamental in genetics as it explains how traits are inherited and expressed in living organisms. Understanding alleles is essential for studying heredity, variations within species, and the principles of Mendelian genetics.

The other options represent different biological concepts that are not synonymous with an allele. For example, cell division processes, such as mitosis or meiosis, refer to how cells replicate or divide; chromosomes are structures housing genes and alleles but are not themselves alleles. Mutations pertain to changes in DNA sequence that can affect gene function and expression but do not define what an allele is.