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The Meaning of Genetic Variation (Grades 9-12)

Students investigate variation in the beta globin gene by identifying base changes that do and do not alter function, and by using several internet-based resources to consider the significance in different environments of the base change associated with sickle cell disease.

Students investigate variation in the beta globin gene by identifying base changes that do and do not alter function, and by using several internet-based resources to consider the significance in different environments of the base change associated with sickle cell disease.

The Meaning of Genetic Variation: Grades 9-12

The Meaning of Genetic Variation: Grades 9-12

Author/Source: National Institutes of Health (via Understanding Evolution)

Overview: Students investigate variation in the beta globin gene by identifying base changes that do and do not alter function, and by using several internet-based resources to consider the significance in different environments of the base change associated with sickle cell disease.

Concepts: This lesson covers the following concepts:

  • Evolution results from selection acting upon genetic variation within a population.
  • Mutations are random, but selection is not; selection is dependent on many factors.
  • Traits that are advantageous often persist in a population.
  • Inherited characteristics affect the likelihood of an organism's survival and reproduction.
  • Depending on environmental conditions, inherited characteristics may be advantageous, neutral, or detrimental.
  • Natural selection acts on phenotype as an expression of genotype.

Grade Level: 9-12

Time: two 50 minute periods

Teacher Background: Explore these links for additional information on the topics covered in this lesson:

Teaching Tips: This activity is the second in a series entitled Human Genetic Variation. We also recommend the introductory activity in this module: Alike but Not the Same. Before beginning this activity, students should understand basic Mendelian patterns of inheritance, especially autosomal-recessive inheritance; the basic structure of DNA; the transcription of DNA to messenger RNA; and the translation of messenger RNA to protein. This activity largely focuses on variation but could easily be extended or modified to emphasize variation's role in evolution to a greater degree.
 
Resource Type: 
Lesson plan