Lecture No. 12 Topic: Expressivity, Penetrance, and Multiple Alleles

Announcements:

• The first of two 50 min-exams is scheduled for Monday, Oct 19. The materials to be examined on will cover from Lecture 1 to this Friday, Oct 16.

• Review in Pierce on pages 129-30, Questions 13, 17, and 22 that relate to multiple alleles.

Pertinent Web Resources:

Example of penetrance

Coat Color in Labrador Retrievers (This site provides good examples of multiple alleles.)

Multiple alleles in Australian shepherd dogs

Pictoral examples of mulitiple alleles

This site provides further information regarding feline polydactyly if interested.

Rules for Nomenclature of Genes, Genetic Markers, Alleles, and Mutations in Mouse and Rat

Notes:

• Questions for you to think about:

  1. .Refer to this hyper-linkedweb site that describes the C locus for coat color in the rabbit. At the C locus there are 5 possible alleles that can occupy this locus. Answers below

  • First how would you list or rank these five alleles in order of dominance (most to least)?
  • What coat color (phenotype) would you expect if animals contained the following genotypes?

    • 1. C C =
    • 2. c^chd c =
    • 3. c^chl c^chd =
    • 4. C c =
    • 5. c^h c^chl =
    • 6. c C =
    • 7. c c^{h =}

 Posted: Oct. 26, 12:10 PM

Answers: C > c ^chd > c ^chl > c^h > c

1. colored; 2. Chinchilla, 3. Chinchilla, 4. Colored, 5. Sable and smoked pearl, 6. Colored, 7.Colored

8. Himilayan