Final answer:
The change in the order of nucleotides in a DNA sequence that codes for a protein is referred to as a genetic mutation, which can result in a wide range of effects on an organism's phenotype.
Step-by-step explanation:
Changes to the order of nucleotides in a segment of DNA that codes for a protein are known as genetic mutations. These changes can have a variety of effects on an organism, ranging from no observable change to significant changes in the phenotype. Mutations can be beneficial, neutral, or harmful, and they are a driving force in the process of evolution. They can occur spontaneously, or be induced by environmental factors such as radiation or chemical exposure. Examples of mutations include the addition, deletion, or substitution of nucleotide bases, and more complex alterations like insertions, deletions, and translocations that can affect the protein coding sequence.