What are different versions of a gene called?

Different versions of a gene are known as alleles. Alleles represent the variations in the sequence of a gene that can result in different traits or characteristics in an organism. For example, a gene responsible for flower color in plants may have multiple alleles that produce different colors, such as red, yellow, or white.

In genetics, the term genotype refers to the specific combination of alleles that an individual has for a given gene, while phenotype refers to the observable traits or characteristics that result from the genotype. Chromosomes are structures that organize and carry genes, but they do not refer specifically to the variations of a gene itself. Thus, alleles specifically denote the different forms a gene can take.