Biology 111 Exam 1 Key

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In mice, coat color (agouti (i.e tan), black, or albino (white)) is controlled through recessive epistasis. The two independently assorting genes are:

- D controls pigment color; D is agouti, d is black

- A controls use of pigment; A allows pigment use, a blocks pigment use.

Imagine two mice with the genotypes Aadd and aaDd that are crossed to produce offspring.

- What are the ratios of the offspring phenotypes that would be produced?

- All would be the same color

- Equal numbers of two phenotypes (1 : 1)

- Equal numbers of three phenotypes (1:1:1)

- 9:3:4

- 2:1:1

- What are the phenotypes of the parental individuals that were crossed in the experiment?

- One is black the other is albino

- One is agouti the other is albino

- One is black the other is agouti

- Both are agouti

- Both are black

- What possible colors off offspring would be produced?

- Just albino offspring

- Albino and agouti offspring

- Albino and black offspring

- Black and agouti offspring

- Black, agouti, and albino offspring

Use the following data to answer Questions 30 - 34:

A laboratory rodent is used in tests of two traits. Trait 1: Furry tail (Na+) is wild type and naked tail (Na) is mutant. Trait 2: Long whiskers (sh+) is wild type and short whiskers (sh) is mutant. A test cross is performed to test for linkage of these two traits.

P0: Na+ sh/Na+ sh X Na sh+/Na sh+

F1: see questions below

Test cross results:

Offspring types number

Furry tail/short whiskers 511

Furry tail/long whiskers 0

Naked tail/short whiskers 0

Naked tail/long whiskers 489

1000

- What is the map distance (in CentiMorgans) separating the genes encoding these traits?

- 5.11

- 2.2

- 48.9

- The genes are so far apart they can’t be accurately mapped

- The genes are so close they can’t accurately be mapped

- What are the phenotypes of the parental generation individuals?

- Na+ sh/Na+ sh is furry tail/short whiskers; Na sh+/Na sh+ is furry tail/long whiskers

- Na+ sh/Na+ sh is furry tail/long whiskers; Na sh+/Na sh+ is naked tail/short whiskers

- Na+ sh/Na+ sh is furry tail/short whiskers; Na sh+/Na sh+ is naked tail/long whiskers

- Na+ sh/Na+ sh is naked tail/short whiskers; Na sh+/Na sh+ is furry tail/long whiskers

- Na+ sh/Na+ sh is naked tail/long whiskers; Na sh+/Na sh+ is naked tail/short whiskers

- What is the genotype of the F1 generation individuals?

- Na+ sh+/Na sh

- Na+ sh/ Na sh+

- Na+ sh+/Na+ sh+

- Na sh/Na sh

- It is impossible to tell because of possible crossing over

- What is the phenotype of the F1 generation individuals?

- Naked tail and long whiskers

- Furry tail and long whiskers

- Naked tail and short whiskers

- Naked tail and long whiskers

- A mix of phenotypes, some parental type and some recombinant types because of crossing over

- How would you characterize the linkage of these traits?

- Completely linked

- Partially linked

- Independently assorting

- So closely linked they must be on different chromosomes

- Unable to answer the question since no parental data is provided

- What form of inheritance best describes the human disease depicted (with genotypes of generation 1 individuals) in the pedigree?

- Sex-linked dominant[pic 1]

- Sex-linked recessive

- Autosomal dominant

- Autosomal recessive

- Autosomal incomplete dominant