Can you determine which statements are correct regarding a dihybrid cross between SsYy X SsYy?

The distribution of the two alleles in each parent plant's gametes will be 50% of gametes are sy; 50% of gametes are SY.

A phenotype ratio of 9:3:3:1 in the offspring of a mating of two organisms heterozygous for two traits is expected when the gene pairs assort independently during meiosis.

Following a SsYy x SsYy cross, 3/4 of the offspring will be heterozygous for both traits.

The gametes of a plant of genotype SsYy should have the genotypes SY, Sy, sY, and sy.

In a dihybrid cross, 1/16 of the offspring will be homozygous for both recessive traits.

A phenotype ratio of 9:3:3:1 in the offspring of a mating of two organisms heterozygous for two traits is expected when the gene pairs assort independently during meiosis.

The gametes of a plant of genotype SsYy should have the genotypes SY, Sy, sY, and sy

In a dihybrid cross, 1/16 of the offspring will be homozygous for both recessive traits.

Explanation:

This is is a typical dihybrid cross involving two distinct genes. One gene has alleles S and s, while the other has alleles Y and y.

In a cross between two dihybrids i.e. SsYy × SsYy, each parent will produce gametes with the following possible allelic combinations: SY, Sy, sY and sy.

Using these gametes in a punnet square (see attached image), 16 possible offsprings will be produced when the alleles of each gene assort independently of one another. The phenotypic ratio will be 9:3:3:1, where;

9/16 will be dominant for both genes

3/16 will be dominant for S gene and recessive for gene Y

3/16 will be dominant for Y gene and recessive for gene S

1/16 will be recessive for both genes.

Oseni Oseni · Answer 2 · 2020-05-11T03:30:35+02:00

Answer:

A phenotype ratio of 9:3:3:1 in the offspring of a mating of two organisms heterozygous for two traits is expected when the gene pairs assort independently during meiosis.

The gametes of a plant of genotype SsYy should have the genotypes SY, Sy, sY, and sy.

In a dihybrid cross, 1/16 of the offspring will be homozygous for both recessive traits.

Explanation:

First, let us look at the cross between SsYy and SsYy.

Each genotype will segregate to give SY, Sy, sY, and sy gametes. These gametes can then be placed in a Punnet's square to give offspring with the following genotypes:

1 SSYY

2 SSYy

2 SsYY

4 SsYy

1 SSyy

1 ssYY

2 Ssyy

2 ssYy

1 ssyy

Assuming the genes assort independently, all S_Y_ genotypes will result in the same phenotypes, all ssY_ will result in the same phenotypes, and all S_yy will result in the same phenotype. Hence, a phenotypic ratio of 9:3:3:1 will result.

Also, from the cross, it can be deduced that 1/16 of the offspring is homozygous for both recessive traits.

Only 1/4 (and not 3/4) are heterozygous for both traits (SsYy).