In a cross between a true-breeding plant bearing smooth, yellow seeds and a true-breeding plant with wrinkled, green seeds, the offspring were all smooth and yellow. What is the genotype of the F₁ plants?
A) SSYY
B) ssyy
C) SsYy
D) ssYY
E) SSyy

Question

Quizplus · Accepted Answer

This is an example of a monohybrid cross, where only one trait (seed texture and color) is studied. In this case, the parental plants are true-breeding, so they can be represented by homozygous genotypes: SSYY for the smooth yellow-seeded plant and syy for the wrinkled green-seeded plant. The F1 generation shows a dominant phenotype: all plants are smooth and yellow. This means that the allele for smooth texture (S) and the allele for yellow color (Y) are dominant over the alleles for wrinkled texture (s) and green color (y), respectively. Therefore, the genotype of the F1 plants must be heterozygous for both traits: SsYy.

In a Cross Between a True-Breeding Plant Bearing Smooth, Yellow