1. Use a Punnett square to predict the offspring in a cross between a dwarf lemon tree (homozygous recessive) and a tall lemon tree (heterozygous).  What is the genotypic ratio of the offspring? What is the phenotypic ratio of the offspring?

Practice Problems, p. 158.
2. Color-blindness is an X-linked recessive disorder. Mike is color-blind. His wife, Meg, is homozygous for the normal color vision allele. Using Punnett squares, derive and compare the genotypic and phenotypic ratios for the offspring of this marriage.
a. What is Mikes's genotype?

b. What is Meg's genotype?

c. What is the genotypic ratio of offspring?

d. What is the phenotypic ratio of offspring?

e. If they have eight children, how many of them would you expect to be color-blind?

Please assist with the following. Please no hand-written work, but typed work and thorough explanations please including Punnett Squares. Please Ignore Sex, as these are not sex-linked traits

Dihybrid Testcrosses

In the following crosses, the wild trait is dominant and the brown trait for eye color and ebony trait for body color are both recessive. You will compare the offspring of homozygous wild flies to the offspring of heterozygous wild flies, when each is crossed with a recessive brown-eyed fly with an ebony body.

7. Perform a monohybrid cross between a wild-type female fly and a male fly with brown eyes and ebony body.
Show results for the F₁ offspring. (NOTE: You will use one of these F₁ flies in the next cross.)
ENTER DATA HERE:

PUNNETT SQUARE:

List the genotypes of the flies in this cross:

List the gametes produced by each fly in this cross:

Show the Punnett Square for the above cross.

Question: By examining the offspring, determine whether the wild-type female parent was homozygous or heterozygous for eye color and body color. How did you arrive at this conclusion?

Question: Are the F₁ offspring homozygous or heterozygous for eye color and body color? How did you arrive at this conclusion?

8. Now perform a cross between one wild-type F₁ offspring from the previous cross and a male fly with brown eyes and ebony body.
ENTER DATA HERE:

PUNNETT SQUARE:

List the genotypes of the flies in this cross:

List the gametes produced by each fly in this cross:

Show the Punnett Square for the above cross.

Question: Even though you already knew the genotype of the wild-type fly used in this cross, how can you tell by examining the offspring of this cross whether the wild-type fly in this cross was homozygous or heterozygous for eye color?

Question: What was the phenotypic ratio for the offspring resulting from this testcross?

1. Cross a homozygous purple Plant (PP) with a homozygous white plans (PP). This is called the P1 cross, and it will produce offspring called the F1 generation. You are given that purple color is dominant to white in this species.

a) What is the genotype of the purple plant?

b) What gametes can the purple plant make?

c) What is the genotype of the white plant?

d) What gametes can the white plant make?

e) Create a Punnett Square explaining this.

f) What is the genotypic Ratio?

g) What is the phenotypic ratio?

2. Cross a homozygous tall yellow seeded plant with a homozygous short green seeded plant. This is called the P1 cross, and it will produce offspring called the F1 generation. Tallness is dominant to shortness, so use a capital T to represent the tallness allele and lower case t to represent the shortness allele. Yellow seeds are dominant to green sees, so use a capital Y to represent the yellow seed allele and a lower case y to represent the green seed allele.

a) What is the genotype of the tall plant?

b) What gametes can the tall plant make?

c) What is the genotype of the short plant?

d) What gametes can the short plant make?

e) Create a punnett square explaining this

f) What is the genotypic ratio of the F1 plants?

g) What is the phenotypic ration of the F1 plants?