What does the term "allele" refer to?

• A. A specific type of gene variant
• B. The overall genetic composition of an organism
• C. A measure of genetic diversity
• D. A principle governing natural selection

Answer: (A)

The term "allele" specifically refers to a variant form of a gene that is located on a particular position on a chromosome. Alleles contribute to the genetic makeup of an organism and can influence specific traits. For example, in a gene that determines flower color, one allele might produce red flowers while another might produce white flowers. This diversity in alleles allows for variation in characteristics within a population, which is fundamental to the principles of genetics.

In contrast, the overall genetic composition of an organism refers to its genotype, which encompasses all the alleles present. A measure of genetic diversity speaks to the variation of alleles within a population rather than defining what an allele is. Lastly, a principle governing natural selection relates to how certain traits become more or less common in a population over time, but it does not define what an allele is. Thus, understanding that an allele is a specific type of gene variant clarifies its role in genetics and inheritance.