What is defined as a change in the DNA sequence?

A mutation is defined as a change in the DNA sequence. Mutations can occur in a variety of ways, such as through errors during DNA replication, environmental factors, or certain chemicals. These changes can affect a single nucleotide or larger segments of DNA, potentially resulting in differences in the traits or characteristics of an organism. The significance of a mutation can vary; some mutations may have no effect, while others can lead to diseases or beneficial adaptations.

Other options refer to different concepts within genetics. Genetic drift, for instance, is a mechanism of evolution that describes changes in allele frequencies in a population due to random sampling effects. A pedigree is a diagram that depicts the biological relationships between individuals, often used to track traits across generations, and a phenotype refers to the observable characteristics or traits of an organism that result from the interaction of its genotype with the environment. Therefore, the specific definition of a mutation as a change in the DNA sequence highlights its foundational role in genetic variation and evolution.