One of the basic requirements of evolution is variation in a population upon which selection can act. One of the sources of variation is mutation in DNA. These changes may or may not be reflected in the ensuing amino acid sequence of a protein. This exercise explores the additive effects of mutation on an amino acid sequence over several generations. The activity is also useful in that it addresses several of the components of Darwin’s theory of evolution through natural selection. There are three separate activities, one regarding sequence change over time, one regarding selective pressure on sequences, and one regarding divergence over time.

Evolution of a DNA Sequence Over Time (PDF)


Intended Audience








Learning Objectives

After completing this activity, students will be able to:

  1. Explain that variation in a sequence can be generated through mutation.
  2. Recognize that successive rounds of mutation lead to further variation in a sequence.
  3. Recognize that sequences that are most closely related in a temporal sense will share the highest degree of similarity.
  4. Demonstrate familiarity with the degeneracy in the amino acid code and how it may mask underlying changes in the DNA sequence.
  5. Use clustering programs to perform an analysis of similarity.
  6. Recognize that sequence similarity in organisms may indicate underlying evolutionary relatedness.


Student Background

Learner should be familiar with Darwin’s theory of evolution by natural selection. Students should also understand that DNA is the hereditary and informational molecule and that information for the synthesis of proteins is encoded in the DNA.



Theory, evolution, natural selection, artificial selection, extant, extinct, neutral mutation, silent mutation, codon, CLUSTAL, dendrogram


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