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Complex Traits

Author(s): Nancy Moreno, PhD.

Dachshunds: Predict the Puppies

Procedure (cont.)

5. Divide students into groups and have them work through the examples on the “Dachshund Predict the Puppies” student sheet. Or, work through most of the questions with the class as a group and assign question “7” as homework or as an exercise for students to conduct in small groups.

Complete instructions from the student sheet.

1. Take a careful look at the two parent dachshund dogs in the photos above. Which dog has the mutation that leads to long hair? Does the dog you identified have one or two copies of the mutation? Explain your answer.

2. Look at the other dog. Can you tell whether this dog also has the mutation for long hair? Explain your answer.

3. Which term refers to the appearance of each of the dogs; for example, the presence of long or short hair (phenotype or genotype)? Which term refers to the DNA variations that are present in each of the dogs (phenotype or genotype)?

4. Just like they use letters to refer to nucleotides (A,C,T,G), biologists also assign letters to specific characters and traits that they observe. For example, the letter “L” can stand for hair length. However, an upper-case “L” is used when only one copy of an allele enables the trait to be seen. A lower-case “l” is used when two copies of an allele are necessary for the trait to be present. Based on this information, how would you write the possible genotype or genotypes of Fido? How would you write the possible genotype or genotypes of Fluffy?

5. If you know the genotype of each parent, is it possible to predict the genotypes and phenotypes (appearance) of each of the offspring? Explain your answer.

Continued on the next slide.

Funded by the following grant(s)

Science Education Partnership Award, NIH

Gene U: Inquiry-based Genomics Learning Experiences for Teachers and Students
Grant Number: 5R25OD011134

Robert Wood Johnson Foundation

Using Learning Technology to Build Human Capital
Grant Number: 57363