Case Study: Earwax...is that Genetic?
Synopsis:
This activity is a case study that draws from the work of Yoshiura et al (2006), where a single base substitution in the ABCC11 gene can result in phenotypic change in earwax consistency. Homozygous recessive individuals (those having the point mutation in which an A substitutes a G) produce dry earwax, while all other individuals produce wet earwax. This research was highlighted in a New York Times article in 2006. That article is used as the main reading of this activity, as it discusses the case without using key terminology and without specifically explaining the genetics behind the observed differences between individuals. This affords instructors the opportunity to challenge students with identifying the genetic concepts that explain the observed earwax differences that are discussed in the article.
This case study was published in the Journal of College Science Teaching (see attached article), and the author presents an example set of questions that students use to complete the activity after reading the NYT article. Discussions are also utilized as part of the overall activity, which has been conducted only after students have otherwise learned Mendelian genetics, allowing them to apply their newly acquired knowledge. Instructors are encouraged to read the Journal of College Science Teaching article, particularly for the discussion of how this activity has been used to, "...promote an in-class discussion and higher-order thinking skills."
Associated Files and Links:
Journal of College Science Teaching Article
Original Primary Research Article
Biology 1113 Learning Outcomes Addressed:
- Apply Mendelian genetics to solve monohybrid and dihybrid crosses.
- Describe the nature and expression of heritable information at the molecular level
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