A version of a gene that can exist in multiple forms is called what?

• A. Allele
• B. Genotype
• C. Phenotype
• D. Food web

Answer: (A)

In genetics, a version of a gene that can exist in multiple forms is called an allele. Alleles are different versions of the same gene at a specific position on a chromosome, caused by variations in the DNA sequence. An individual typically carries two alleles for each gene, one inherited from each parent, and the combination of these two alleles makes up the genotype. The phenotype is what you actually observe—the visible trait that results from the genotype and how the alleles interact in the organism. For example, a gene that controls flower color might have an allele for purple pigment and another for white pigment; the plant’s phenotype will depend on which alleles it has. The other term listed, a food web, is unrelated to genes and traits.