What is a mutation?

A mutation is defined as a change in the DNA sequence of an organism's genome. This change can occur in various forms, such as substitutions, deletions, insertions, or even larger structural changes within chromosomes. Mutations can be spontaneous, arising from errors during DNA replication, or induced by external factors like radiation or chemicals.

Understanding mutations is critical because they are the primary source of genetic variation, which can lead to evolutionary changes over time. Some mutations may have little or no effect on the organism, while others can be beneficial or detrimental, influencing traits such as resistance to diseases or susceptibility to certain conditions.

The other choices represent concepts that do not accurately define what a mutation is. The option about an increase in genetic material refers to processes such as duplication or polyploidy rather than mutations themselves. The idea of a regular alteration in protein structure relates to changes in proteins due to mutations, but this does not capture the essence of what a mutation is. Lastly, introducing a new cell type involves differentiation and developmental processes rather than changes in the DNA sequence. Thus, the accurate definition of a mutation is, indeed, a change in the DNA sequence.