Genetics and Molecular Biology Practice Exam

When DNA is copied, mistakes can occur that alter the genetic material of a cell. This kind of change is called a mutation. A mutation is any heritable alteration in the DNA sequence, arising from replication errors, chemical damage, or environmental factors. This concept is distinct from variation, which refers to differences observed among individuals or populations (mutations can cause variation, but variation is a broader idea). It’s also separate from evolution, which describes how allele frequencies in a population change over generations, not a single DNA change. Gene duplication is a specific event in which a DNA segment is copied, creating an extra gene copy; it’s one way a mutation can arise, but it’s not the general term for a DNA change.