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Complex Traits

Author(s): Nancy Moreno, PhD.

1. Bichon Frise

Procedure (cont.)

5. Tell students, Let’s figure out what the genotype of the dog must be, based on the traits that we have observed and recorded.

  • Since the Bichon has long hair, which combination of alleles is possible? [“ll” is the only possible genotype.]
  • We determined that the hair is curly. What genotypes are possible? [Since the Bichon is clearly “curly,” and not wavy or straight, the genotype is CC].
  • Since the dog has furnishing, what are the possible genotypes? [It is not possible to know if the individual pictured is homozygous, FF, or heterozygous, Ff. However, since the trait appears consistently within members of the breed, it is reasonable to assume that most individuals of this breed are homozygous for the furnishings allele, FF].

6. Let each group work through the remaining dog breeds. (Slides 33–40 contain enlarged images all eight dogs for use as needed.) Tell students to determine the phenotypes of all the dogs, before proceeding to the genotypes. If you have Internet access in your classroom, students may want to access additional photographs of the different breeds to look for characteristics, such as furnishings. 

7. Have the groups report on their conclusions regarding the genotype and phenotypes of each breed, by asking each group to present the findings for a different breed. Or, have each group submit a written explanation of the decisions they made regarding each breed. 

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