Final answer:
A mutation is a heritable change in the DNA sequence of an organism. It can result in a recognizable change in phenotype and is the ultimate source of new genetic material in a species.
Step-by-step explanation:
A mutation is a heritable change in the DNA sequence of an organism. The resulting organism, called a mutant, may have a recognizable change in phenotype compared to the wild type. A change in the DNA sequence can lead to an altered amino acid sequence in a protein, which can result in an altered phenotype for the cell and organism. Mutations can occur due to errors during DNA replication, exposure to mutagens, or viral infections.
They can be harmful, beneficial, or have no effect on an organism. Somatic mutations affect daughter cells but are not passed on to offspring, while germline mutations occur in eggs or sperm and are passed to the offspring. Mutations are essential for evolution to occur and are the ultimate source of new genetic material in a species.