High School

We appreciate your visit to MONOHYBRID INHERITANCE Crosses of this type involve only a single pair of alleles 1 In fruit flies Drosophila melanogaster red eye is dominant to pink. This page offers clear insights and highlights the essential aspects of the topic. Our goal is to provide a helpful and engaging learning experience. Explore the content and find the answers you need!

**MONOHYBRID INHERITANCE:** Crosses of this type involve only a single pair of alleles.

1. In fruit flies (*Drosophila melanogaster*), red-eye is dominant to pink-eye. By crossing a homozygous pink-eyed male fly to a heterozygous red-eyed female fly, 60 offspring were produced. How many would you expect to be red-eyed and how many pink-eyed?

2. Albinism, a recessive trait, commonly occurs in animals. Seven brown and six albino mice were born to parents who were likewise brown and albino. What is the genotype of the brown parent?

3. Supposing brown eyes in people (B) is dominant to blue (b):

A. Could a marriage between two brown-eyed people produce a blue-eyed child?

B. Could a marriage between two blue-eyed people produce a brown-eyed child?

C. Could a marriage between a homozygous brown-eyed person and a blue-eyed person result in blue-eyed children?

Explain all of your answers by supplying the proper symbols. Brown eye = B, blue eye = b.

4. Woodrats are medium-sized rodents with lots of interesting behaviors. You may know them as packrats. Let’s assume that the trait of bringing home shiny objects (H) is controlled by a single gene and is dominant to the trait of carrying home only dull objects (h). If two heterozygous individuals are crossed, what are the potential genotypes of their offspring?

**DIHYBRID INHERITANCE:** In these crosses, two pairs of alleles are involved.

5. Wolves are sometimes observed to have black coats and blue eyes. Assume that normal grey coat color (G) is dominant to black (g) and brown eyes (B) are dominant to blue (b). Suppose an alpha male who is black with blue eyes mates with the alpha female who is heterozygous for grey color and brown eyes. Out of 16 offspring, how many would be expected to have grey coat color with brown eyes? Black coat color with blue eyes?

- G = dominant grey coat
- g = recessive black coat
- B = dominant brown eye
- b = recessive blue eye

Answer :

Final Answer:

1. You would expect 2 red-eyed and 2 pink-eyed offspring.

2. The brown parent must be heterozygous (Aa).

3. a. Yes, this is possible if both parents are heterozygous carriers of the blue-eyed allele (Bb).

b. No, this is not possible. Both blue-eyed individuals would need to have two copies of the blue-eyed allele (bb), so they can only pass on blue-eyed alleles to their children.

c. No, it's not possible. The homozygous brown-eyed person (BB) can only pass on brown-eyed alleles (B) to their offspring.

4. Potential genotypes of their offspring: HH, Hh, Hh, hh

5. You would expect 9 offspring with grey coat and brown eyes, and 1 offspring with black coat and blue eyes.

Explanation:

#1: In fruit flies (Drosophila melanogaster)

Red-eye (R) is dominant to pink-eye (r).

Cross between a homozygous pink-eyed male (rr) and a heterozygous red-eyed female (Rr).

60 offspring produced.

You can use a Punnett square to determine the expected offspring:

Parental genotypes: Male (rr) × Female (Rr)

Rr (Red-eyed) rr (Pink-eyed)

Rr Rr (Red-eyed) rr (Pink-eyed)

Rr Rr (Red-eyed) rr (Pink-eyed)

Out of the four possible combinations, 2 would result in red-eyed (Rr) offspring and 2 would result in pink-eyed (rr) offspring.

So, you would expect 2 red-eyed and 2 pink-eyed offspring.

#2: Albinism in mice

Albinism (aa) is recessive, brown (AA or Aa) is dominant.

Parents: 7 brown (Aa or AA) and 6 albino (aa) mice.

Since all albino mice are homozygous recessive (aa), the brown parent must be heterozygous (Aa) because it's producing both brown (dominant) and albino (recessive) offspring.

#3: Brown and blue eye inheritance in humans

Yes, this is possible if both parents are heterozygous carriers of the blue-eyed allele (Bb).

No, this is not possible. Both blue-eyed individuals would need to have two copies of the blue-eyed allele (bb), so they can only pass on blue-eyed alleles to their children.

No, it's not possible. The homozygous brown-eyed person (BB) can only pass on brown-eyed alleles (B) to their offspring.

#4: Woodrats and shiny objects

Shiny objects (H) are dominant to dull objects (h).

Cross between two heterozygous individuals (Hh).

Potential genotypes of their offspring: HH, Hh, Hh, hh

#5: Wolves coat color and eye color

Grey coat (G) is dominant to black coat (g).

Brown eyes (B) are dominant to blue eyes (b).

Alpha male (ggBB) mates with heterozygous alpha female (GgBb).

16 offspring.

You can use a Punnett square to determine the expected offspring:

Parental genotypes: Male (ggBB) × Female (GgBb)

Out of the sixteen possible combinations, 9 would result in grey coat with brown eyes, 3 would result in grey coat with blue eyes, 3 would result in black coat with brown eyes, and 1 would result in black coat with blue eyes.

So, you would expect 9 offspring with grey coat and brown eyes, and 1 offspring with black coat and blue eyes.


Learn more about genotype at https://brainly.com/question/33247754

#SPJ11

Thanks for taking the time to read MONOHYBRID INHERITANCE Crosses of this type involve only a single pair of alleles 1 In fruit flies Drosophila melanogaster red eye is dominant to pink. We hope the insights shared have been valuable and enhanced your understanding of the topic. Don�t hesitate to browse our website for more informative and engaging content!

Rewritten by : Barada