You paid $1,000,000 to purchase a black Angus bull named Maxwell that was advertised as a "pure-breeding" black Angus cow (BB; B = black and b = brown; B is dominant to b)
You mated Maxwell with Bessie, who also was advertised as a pure-breeding black Angus cow (BB); as you expected, all of their offspring were black. Several years later, you mated a pair of these offspring several times (F1 × F1) and found that approximately 25% of the F2 progeny were brown instead of black. What were the actual genotypes of the original cross (Maxwell × Bessie)?
A) BB × BB
B) Bb × BB
C) Bb × Bb
D) BB × bb
E) bb × bb
Answer: B
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