1. Paw color in Space Foxes is complicated but controlled by a single gene. Many paw colors are present in a
Space Fox: blue, black, white, green, gray and each of the preceding colors are present individually with black
patch variants except white or gray- there are no white with black patches or gray with black patches.
Also since black is black, you can’t discern a black patch on black. [The goal of this question is to see
where the data and your understanding of Mendelian inheritance takes you, even if the underlying mechanism
is fanciful or hard to understand on a molecular level].
True breeding white x true breeding blue Space Foxes give all blue F1. In F2, there are 3:1 Blue:White.
True breeding blue x true breeding green give all blue F1. In F2, there are 3:1 Blue: Green.
True breeding green and white give all green F1. In F2, there are 3:1 Green to White.
True breeding black x true breeding white gives all gray F1. In F2 there are 1:2:1 Black:Gray:White.
True breeding black x true breeding blue gives all blue F1. In F2, there are 3:1 Blue:Black.
True breeding black x true breeding green gives all green F1. In F2, there are 3:1 Green to Black
Use this genotype key for the above colors
True breeding color Genotype keyBlack fBlackBlue fBlueWhite fWGreen fG14A. What are the dominance relationships between the alleles noted above that you would guess from the
above information? Use > for dominant, = for codominant, ? for partial dominance. (1 point).
You decide to do some crosses with individuals from the colony to figure out how black patching works. You
get the following results. Use fBP or FBP to represent black patches.
Cross 1: Blue with black patches crossed with true breeding green you get:1/2 green with black patches and 1/2 blue.Cross 1A: When you cross the green with black patches with each other, they always give 2/3 green
with black patches and 1/3 green. Cross 1B: When you cross the F1 blue foxes with each other, you
get 3:1 blue to green.
Cross 2: Green with black patches crossed with true breeding blue you get:
1/2 blue with black patches and 1/2 just blue.
Cross 2A: When you cross the blue with black patches with each other, they always give 2/3 blue with
black patches and 1/3 blue. Cross 2B: When you cross the F1 blue foxes with each other, you get 3:1
blue to green.
Designate genotypes for this cross and explain the genotype of the blue (or green) with black patched
individuals (3 points).
Example answer in box (x/y and a/b = relevant fractions.x:y:z = relevant proportions)
1B. Cross 1, 1A, 1B Genotypes (Pheno)(0.5 points) 1C. Cross 2, 2A, 2B Genotypes (Pheno) (0.5 points)
1D Explanation (1 points)
You find when you cross black pawed foxes with each other, some lines appear to breed true. However, you
get the following scenarios when you cross some black pawed foxes to true breeding white:
Scenario 1: Some black pawed foxes crossed by white give: all gray F1, 1:2:1 black:gray:white in F2.
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