What are alleles?

Alleles are defined as different versions of the same gene that can exist at a specific locus on a chromosome. These variations can result in different traits or characteristics being expressed in an organism, such as eye color or blood type. Each individual typically inherits one allele from each parent for a gene, leading to various combinations that contribute to genetic diversity.

For example, for the gene that determines flower color in pea plants, one allele might code for purple flowers while another allele codes for white flowers. The presence of these different alleles is what allows for the observable variation in traits among individuals of the same species.

The other options, while related to genetics, do not accurately define alleles. Identifying different genes located on the same chromosome refers more to the concept of loci and genetic mapping rather than alleles themselves. Identical copies of a gene refer to homozygous conditions rather than allelic differences. Gene mutations represent changes in the DNA sequence of a gene, but these changes do not represent different versions of the same gene. Therefore, the definition of alleles as different versions of the same gene captures their essence in genetics.