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Stalking the Genetic Basis of a Trait

Illustration of a teosinte plant next to a corn plant

Topic

  • Genetics
  • Gene Expression & Regulation
  • Anatomy & Physiology
  • Plant Anatomy & Physiology
  • Evolution
  • Artificial Selection
  • Math & Computational Skills
  • Data Analysis

Resource Type

  • Activities
  • Lessons

Level

High School — AP/IBCollege
Used In
1 BioInteractive Playlists
Saved By
13 Users
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Description

This activity supports the film Popped Secret: The Mysterious Origin of Corn. Students analyze data on the expression of the tb1 gene to explain how variations in this gene played a role in the evolution of corn.

The activity starts with students watching the film, which describes how corn evolved through artificial selection from a central American grass called teosinte. Researcher John Doebley discovered that the differences between corn and teosinte are largely the result of variations in just a handful of genes.

In this activity, students learn that one of those genes is called teosinte branched 1, or tb1. They then analyze differences in both the coding and regulatory regions of the tb1 gene in corn and teosinte and make claims about the effects of those differences on the expression of the tb1 gene, on the TB1 protein, on the expression of other genes, and on the phenotype of the plants.

Student Learning Targets

  • Analyze amino acid and DNA sequences to determine that differences in the coding region of tb1 are not the cause of phenotypic differences between corn and teosinte but are evidence of a close evolutionary relationship.

  • Construct an explanation based on evidence for how the structure of DNA in a regulatory region determines the expression of proteins that further affect the expression of other genes.

Estimated Time

One to two 50-minute class periods.

Key Terms

corn, gene expression, gene regulation, Hopscotch insertion, maize, mutation, phenotype, regulatory region, tb1 gene, teosinte

Primary Literature

Studer, Anthony, Qiong Zhao, Jeffrey Ross-Ibarra, and John Doebley. “Identification of a functional transposon insertion in the maize domestication gene tb1.” Nature Genetics 43, 11, (2011): 1160–1163. https://doi.org/10.1038/ng.942.

Studer, Anthony J., Huai Wang, and John F. Doebley. “Selection during maize domestication targeted a gene network controlling plant and inflorescence architecture.” Genetics 207, 2 (2017): 755–765. https://doi.org/10.1534/genetics.117.300071.  

Terms of Use

The resource is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International license. No rights are granted to use HHMI’s or BioInteractive’s names or logos independent from this Resource or in any derivative works.

Accessibility Level (WCAG compliance)

PDF files meet criteria.

Version History

Date Published 11.08.17
Date Updated 07.30.19

NGSS (2013)

HS-LS1-1, HS-LS3-1, HS-LS4-1; SEP1, SEP4, SEP6

AP Biology (2019)

EVO-1.N, IST-1.J, IST-1.K, IST-1.N, IST-1.P, IST-2.A, IST-2.B, IST-2.C, IST-2.D, IST-4.B; SP1, SP3, SP4, SP6

IB Biology (2016)

3.1, 3.4, 7.2

IB Environmental Systems and Societies (2017)

3.2

Common Core (2010)

ELA.RST.9–12.7, ELA.WHST.9–12.1

Vision and Change (2009)

CC1, CC3; DP1

Materials

Educator Materials (PDF) 443 KB
Student Handout (PDF) 584 KB

Use This Resource With

Video Resource
Popped Secret: The Mysterious Origin of Corn

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Interactive Videos
Interactive Assessment for Popped Secret: The Mysterious Origin of Corn
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This Resource Appears in the Following Playlists

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