The Teosinte Hypothesis
In this activity, students further explore the short film Popped Secret: The Mysterious Origin of Corn, by working through the mathematical concepts behind George Beadle’s claim that teosinte is the wild ancestor of maize.
George Beadle was the first to propose that teosinte is the wild ancestor of maize. At first, few scientists agreed with this hypothesis because there did not seem to be enough supporting evidence. Later in his career, Dr. Beadle undertook a huge genetic experiment to find more evidence.
Students will use Punnett squares to model crosses if one, two, or three genes are involved in determining the differences between teosinte and maize. Then, they develop a mathematical model to make further predictions, and use those to explain the main conclusion of Dr. Beadle’s research and how it supports his hypothesis about maize’s origins.
Student Learning Targets
- Calculate and predict the probability of offspring genotypes and phenotypes based on genetic crosses.
- Compare different methods of modeling genetic predictions.
allele, genotype, maize, phenotype, Punnett square, teosinte
Doebley, J. “The Genetics of Maize Evolution.” Annual Review of Genetics 38, 1 (2004): 37–59. https://doi.org/10.1146/annurev.genet.38.072902.092425.
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HS-LS3-3, HS-LS4-3; SEP2, SEP4, SEP5
3.A.3; SP1, SP2, SP5
Math.A-CED.1, Math.S-IC.2; MP1, MP4, MP8
CC3; DP2, DP3