Kaplan Nursing Entrance Practice Exam

What are alleles?

1. Different species of organisms

2. Different forms of a gene

3. Identical copies of DNA

4. Males and females of a species

The correct answer is: Different forms of a gene

Alleles are defined as different forms of a gene that exist at the same locus on homologous chromosomes. Each individual inherits two alleles for each gene, one from each parent. These alleles can produce variation in traits, such as eye color or blood type, because they may code for different versions of a specific characteristic. For example, in a gene that determines flower color, one allele might result in red flowers while another could result in white flowers. This variation is crucial for the processes of evolution and natural selection. Understanding the role of alleles is fundamental in genetics, as they contribute to the diversity observed in traits among individuals within a species.