Question

When crossing a true-breeding white wool sheep with a true-breeding black wool sheep, all of the offspring (F1 generation) have white wool. In the F1 generation, the allele for white wool would be found in:a. about 50% of the female gametes and 50% of the male gametes produced by the F1 sheepb. all of the female gametes and none of the male gametes produced by F1 sheepc. all of the male gametes and none of the female gametes produced by F1 sheepd. none of the male gametes or female gametes produced by F1 sheep

Answer 1

If one of the parents were homozygous for the white wool and the other is homozygous for the black wool, we can assume that the alleles for white wool are dominant (as the offspring presented only white wool). In that case the cross would be (white) WW x ww (black).

As we can see, all of the offspring would be heterozygous Ww, expressing the dominant trait (white).

As they are all Ww and the gametes will present only one of the alleles (because gamete cells has only half of the genetic material compared to other cells), the gametes will either present only W or w. Proportionally, it is expected that half of them will have the W allele (for white wool), regardless of being male or female gametes.

Therefore, the correct answer is a. about 50% of the female gametes and 50% of the male gametes produced by the F1 sheep.