Kaplan Nursing Entrance Practice Exam

What distinguishes a mutation that creates a new allele?

1. It can occur in both eggs and sperm

2. It is always harmful

3. It cannot be inherited

4. It only affects somatic cells

The correct answer is: It can occur in both eggs and sperm

A mutation that creates a new allele is distinguished by its potential to occur in both eggs and sperm. This is significant because mutations in these germline cells can be passed on to future generations, contributing to genetic diversity within a population. When a mutation affects the DNA sequence in these cells, it may lead to variations in traits that can be inherited, thereby giving rise to new alleles. In contrast, the other options do not accurately characterize the nature of mutations that create new alleles. While some mutations can be harmful, not all are detrimental; some may be neutral or even beneficial. Additionally, mutations that create new alleles are typically found in germline cells rather than somatic cells, as somatic mutations cannot be passed to offspring. Thus, the key aspect of the correct choice is its emphasis on the germline's role in inheritance and genetic diversity.