You self-fertilize a pea plant and find that the resultant progeny plants all make only yellow seeds.

a) Was the original plant most likely a heterozygote or a homozygote for the seed color gene?

b) Is it possible for you to know, from this information alone, whether the yellow seed color allele is a dominant or recessive allele?

A) should be "Heterozygote" and B) should be "No"
However, I was thinking that if A) was a heterozygote, I thought 1/4 of progeny would show recessive trait (something other than yellow). This also led me to answer B) wrong, I thought it would be yes.

Any explanations would be much appreciated!

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Keith LeannonLv2

18 Sep 2018

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In peas, the dominant seed shape is round and the recessive iswrinkled(w). The dominant trait for pod color is green andrecessive is yellow (y). A plant with round seeds and green podsthat i heterozygous only for the color trait is crossed with aplant that has wrinkled seeds and yellow pods, and the resulting F1progeny are selfed(self fertilized).
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Thank you