Question

What is the Expected Phenotypic Ratio of a Cross Between an RrYy and an RRYY Individual?

Answer 1

Dihybrid cross:

1. It's a cross between two organisms where both individuals are heterozygous for two different traits and parents have a different pair of alleles for each trait.
2. The dihybrid cross between RrYy and RRYY will give the plants dominant traits. That is a Round shape and yellow seed color (RY)
3. The homozygous dominant RRYY will produce only one type of gametes which is RY.
4. The other parent is heterozygous containing both dominant and recessive alleles that will produce 4 types of gametes, they are RY, rY, Ry and ry
5. The Punnett square will give four types of genotype, viz., RRYY, RrYY, RRYy, and RrYy.
6. All the gametes have dominant traits because of the presence of R and Y dominant alleles.

Results of a cross between RrYy and RRYY

	RY	Ry	rY	ry
RY	RRYY	RRYy	RrYY	RrYy
RY	RRYY	RRYy	RrYY	RrYy
RY	RRYY	RRYy	RrYY	RrYy
RY	RRYY	RRYy	RrYY	RrYy

RRYY- Round shape and yellow color

RRYy- Round shape and yellow color

RrYY- Round shape and yellow color

RrYy- Round shape and yellow color

The dihybrid cross between RrYy and RRYY will give all the plants the phenotype of Round and yellow seed, i.e. all the plants will show the dominant trait, which is round shape and yellow color seed.