Final answer:
The genotypic ratio in the offspring would be 1 YY: 2 Yy: 1 yy. The phenotypic ratio would be 3 yellow: 1 green. In a two-locus cross (involving two gene loci), the phenotypic ratios of the offspring are determined by the combination of alleles inherited from each parent. Let's analyze the cross between ttYy (parent 1) and Ttyy (parent 2).
Step-by-step explanation:
A self-cross of one of the Yy heterozygous offspring can be represented in a 2 × 2 Punnett square because each parent can donate one of two different alleles. Therefore, the offspring can potentially have one of four allele combinations: YY, Yy, yy, or yy (Figure 12.4). Notice that there are two ways to obtain the Yy genotype: a Y from the egg and a y from the sperm, or a y from the egg and a y from the sperm. Both of these possibilities must be counted. Therefore, the genotypic ratio in the offspring would be 1 YY: 2 Yy: 1 yy.
Applying the sum rule of probability, assuming that fertilization is a random event, we expect the offspring to exhibit a phenotypic ratio of 3 yellow: 1 green. In a two-locus cross (involving two gene loci), the phenotypic ratios of the offspring are determined by the combination of alleles inherited from each parent. Let's analyze the cross between ttYy (parent 1) and Ttyy (parent 2). This is because both YY and Yy offspring have yellow seeds and are phenotypically identical.