Dihybrid Cross Practice Problems

In a fish, gold skin color (G) is dominant to black skin color (g) and split tail fin (S) is dominant to single tail fin (s). A breeder crosses a male fish having GgSs genotype with a female fish having ggSs genotype. Determine the expected phenotypic ratio of the progeny.

In a fish, gold skin color (G) is dominant to black skin color (g) and split tail fin (S) is dominant to single tail fin (s). Breeding between two fish of unknown genotypes results in the following phenotypic ratios in the progeny: 1/4 gold, split tail fin; 1/4 gold, single tail fin; 1/4 black, split tail fin, and 1/4 black, single tail fin. What are the genotypes of the two fish used for breeding?

A cross was performed between individuals with the AABB and aabb genotypes. The F₁ progeny of this cross were then self-fertilized. What is the probability that the F₂ progeny will have the same phenotype as their parents?

Assuming simple dominance and independent assortment, the genotypic ratio of the AaBb x AaBb cross will be:

A cross is performed between individuals with the AaBb and AaBB genotypes. What is the phenotypic ratio expected for this cross?

Which of the following sentences regarding dihybrid cross is false?

If a tall (TT) green (GG) pea plant is crossed with a short (tt) white (gg) pea plant, all its offspring will be:

Gregor Mendel was able to develop his law of independent assortment through dihybrid cross-pollination experiments. According to this law, alleles separate during _____, creating gametes with one allele each for a single trait.

Blue eyes with black coats are not often seen on wolves. Assume that normal coat color (N) dominates over black (n) and that brown eyes (B) dominate over blue (b). An alpha male is mated with an alpha female. What will be the probability of a wolf's offspring having blue eyes and a black coat if both parents are heterozygous for eye and coat color? (Note: the alleles for coat color and eye color are not linked.)

A punnet square is formed by using the following data:

 1. Dominant allele for purple flower = P 

2. Recessive allele for white flower = p 

3. Dominant allele for tall plant = T 

4. Recessive allele for short plant = t 

From the punnet square below, identify the probability of plants being homozygous for tall and purple flowers.

True-breeder round and yellow-seeded pea plants were crossed with a true-breeder wrinkled and green-seeded pea plant to raise F₁ offspring. What is true for the F₁ generation of this cross? (Note: The allele "Y", which produces the yellow color of the seed in the pea plant, is completely dominant over "y", which makes the seed green. The allele for the round (R) shape is completely dominant over the wrinkled shape (r).

Alleles "A" and "B" are completely dominant over "a" and "b", respectively. Following the independent assortment of genes, what percentage of offspring will be heterozygous (AaBb) for both gene pairs as a result of a cross between two parents with the genotypes AaBB and Aabb?

The genes for wing color and size in beetles assort independently. The red color allele (R) of the wing is dominant over the white color allele (r), whereas the normal wing allele (L) is dominant over the short wing allele (l). Determine the phenotypic ratio of red to white-winged offspring produced when a beetle with normal red wings (heterozygous for both traits) is mated with a beetle having short white wings.

Hemophilia is an X-linked recessive disorder because the abnormal gene that causes it is located on the X-chromosome. The eye color gene, on the other hand, is located on chromosome 15. Determine the expected ratios of hemophilic and brown-eyed female and male offspring of the F₂ generation if a normal female with homozygous blue eyes marries a hemophilic man with homozygous brown eyes. (Remember that brown eye color is dominant over blue eye color).

In doing a test cross, the genotype in question is crossed with a _______ genotype.

In crossing a black and short guinea pig (Bbss) with a white and long (bbSs) guinea pig, what is the phenotypic ratio of black to white offspring phenotypes?

The tall (B) and purple flower (C) pea plants are dominant over the short (b) and white flower (c) pea plants. If a tall and purple flower pea plant with genotype BbCc is allowed to self-fertilize, which of the following genotypes can produce short purple flowers?

Alleles "A" and "B" are completely dominant over "a" and "b," respectively. Consider the independent assortment of genes and predict the probability of having the AaBb genotype in a cross between AABB and aabb.

The allele "Y," which produces the yellow color of the seed in the pea plant, is completely dominant over "y," which makes the seed green. The allele for the round shape (R) is completely dominant over the wrinkled shape (r). What will be the phenotypic ratio of a cross between RrYy and RrYy?

A tall pea plant with purple flowers (BbCc) is crossed with another tall pea plant with purple flowers of the same genotype. What is the probability of producing short and purple flower offspring?

A tall pea plant with purple flowers (BbCc) is crossed with another tall pea plant with purple flowers of the same genotype. Identify which genotype has a 1/16 chance of appearing in the F1 generation.

If yellow and round seed is dominant over green and wrinkled seed, the following are the possible genotypes of yellow and round seeds except:

If a black and short guinea pig (Bbss) is crossed with a white and long (bbSs) guinea pig, what is the probability of producing a white and short guinea pig in the F1 generation?

If a yellow and round pea (GgWw)  is crossed with a green and round pea (ggWw), using the Punnet square, what is the probability of producing a yellow and wrinkled pea in the F1 generation?