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Name:
Last 4 digits of student ID:
Lab section:ETZ6AB
Instructor name: Elaine Palucki
Lab 6: Genetic Crosses

Read Chapter 7 and print out the sample genetic cross to use as a guide.
Below is a list of the Phenotypes used in this lab. These are all single gene traits that
show complete dominance
Trait
Flower color
Plant Height
Seed Shape
Seed Color

Dominant phenotype
Purple flowers
Tall plants
Round seeds
Yellow seeds

Recessive Phenotype
White flowers
Short Plants
Wrinkled seeds
Green seeds

Part I: Symbols and definitions:
1. Please define each of these words (1 pt)
Allele: An allele is an alternative form of a gene (one member of a pair) that is located at a
specific position on a specific chromosome.
Homozygous: an individual (or a condition in a cell or an organism) containing two copies of the
same allele for a particular trait located at similar positions on paired chromosomes; Having two
identical alleles that code for the same trait.
Herterozygous: an individual (or a condition in a cell or an organism) containing two different
alleles for a particular trait; Having dissimilar alleles that code for the same gene or trait.
Gentoype: The entire set of genes in an organism; A set of alleles that determines the expression
of a particular characteristic or trait (phenotype)

2. For each trait indicate the genotypes that are possible. Use the first letter of the dominant trait
to indicate the trait. (2pts)
Trait
Flower color
Plant Height
Seed Shape
Seed Color

Dominant genotype(s)
Purple =
Tall =
Round =
Yellow =

Recessive genotype(s)
White =
Short =
Wrinkled =
Green

Pick three of the crosses to complete using any 3 of the last 4 digits of your student ID.
Circle the numbers of the crosses you are doing in column 1 below.
Cross
Number
0
1
2
3
4
5
6
7
8
9

Male parent traits

Female parent traits

Heterozygous for flower color
Homozygous dominant for height
Heterozygous for flower color
Heterozygous for height
Heterozgyous for flower color
Heterozygous for seed color
Homozygous recessive for flower color
Heterozygous for seed color
Homozygous recessive for seed shape
Homozygous recessive for height
Heterozygous for seed shape
Heterozygous for height
Homozygous dominant for flower color
Homozygous recessive for seed shape
Heterozygous for flower color
Homozygous recessive for seed shape
Heterozygous for seed shape
Homozygous recessive for seed color
Heterozygous for seed shape
Heterozygous for seed color

Heterozygous for flower color
Homozygous dominant for height
Homozygous dominant for flower color
Heterozygous for height
Heterozgyous for flower color
Heterozygous for seed color
Homozygous dominant for flower color
Heterozygous for seed color
Heterozygous for seed shape
Heterozygous for height
Heterozygous for seed shape
Homozygous recessive for height
Homozygous recessive for flower color
Homozygous dominant for seed shape
Heterozygous for flower color
Homozygous recessive for seed shape
Homozygous recessive for seed shape
Homozygous recessive for seed color
Homozygous recessive for seed shape
Homozygous dominant for seed color

Now you can use the charts and Punnett squares on each of the following pages to complete
your crosses.

Cross 1: Please write the number of the cross you are performing: ______________
Then fill in the genotype and phenotype for each parent below. Use the sample problem for a
guide.
Sex
Male
Female

Genotype

Phenotype

Step 1: Determine the different gamete combinations that each parent can contribute to the
offspring. Check the hint from the sample problem when you are doing this.

Sex
Male
Female

Gamete 1

Gamete 2

Gamete 3

Gamete 4

Step 2: Fill in the Punnett Square below
Male gametes
place across ?
Female Gametes:
Place below: ?

Step 3: Find the Phenotype of each of the 16 combinations in your Punnett Square page.
Phenotype you’ve found in offspring

Number of offspring with this phenotype

Cross 2: Please write the number of the cross you are performing: ______________
Then fill in the genotype and phenotype for each parent below.
Sex
Male
Female

Genotype

Phenotype

Step 1: Determine the different gamete combinations that each parent can contribute to the
offspring.
Sex
Male
Female

Gamete 1

Gamete 2

Gamete 3

Gamete 4

Step 2: Fill in the Punnett Square below
Male gametes
place across ?
Female Gametes:
Place below: ?

Step 3: Find the Phenotype of each of the 16 combinations in your Punnett Square page.
Phenotype you’ve found in offspring

Number of offspring with this phenotype

Cross 3: Please write the number of the cross you are performing: ______________
Then fill in the genotype and phenotype for each parent below.
Sex
Male
Female

Genotype

Phenotype

Step 1: Determine the different gamete combinations that each parent can contribute to the
offspring.
Sex
Male
Female

Gamete 1

Gamete 2

Gamete 3

Gamete 4

Step 2: Fill in the Punnett Square below
Male gametes
place across ?
Female Gametes:
Place below: ?

Step 3: Find the Phenotype of each of the 16 combinations in your Punnett Square page.
Phenotype you’ve found in offspring

Number of offspring with this phenotype

Questions:
1. Are gametes haploid or diploid? What about the offspring, are they haploid or diploid? (1pt)

2. A) Can two Tall and Purple flowered parents produce offspring that are Short and have White
seeds?
Explain using a Punnett square why you think this outcome is possible or not. (1pt)

B) Can two short and green seeded parents produce offspring that are tall and have yellow
seeds?
Explain using a Punnett square why you think this outcome is possible or not. (1pt)