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In mice, the allele for black fur is dominant to the allele for brown fur.

If a male homozygous black mouse is crossed with a female brown mouse, what percentage of the F2 offspring do you predict will be homozygous?

User Zaboco
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1 Answer

4 votes

Answer:

50%

Step-by-step explanation:

The allele for black fur (B) is dominant to the allele for brown fur (b).

  • BB or Bb = black fur
  • bb = brown fur

A male homozygous black mouse (BB) is crossed with a female brown mouse (bb). The male parent only produces B gametes and the female parent only produces b gametes. The F1 offspring will be 100% heterozygous Bb.

The F1 individuals will produce B and b gametes. If we cross the F1 individuals to each other (Bb x Bb), we'll get the following F2 offspring:

  • 25% BB homozygous dominant
  • 50% Bb heterozygous
  • 25% bb homozygous recessive

So 50% of the F2 will be homozygous (BB or bb).

User Britto Thomas
by
7.6k points
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