Genetics of the Baxter Slug
Name____________________
Learning Targets
I can relate genotypes to phenotypes
I can show how Meiosis selects alleles for sperm and egg cells
I can explain how genes and traits are passed from parents to offspring
Introduction
Baxter Slugs reproduces sexually, just like humans. These traits are controlled by their genes (found on
chromosomes) and have two different alleles each:
Trait
Eye Shape
Body Pattern
Teeth
Gender
Phenotype
Round
Draw Phenotype
Symbol for Allele
R
Star
r
Polka-Dotted
D
Striped
d
Buck-Teeth
B
Fangs
b
Male
Y
Female
X
In this activity, you will analyze the genotypes and phenotypes of two parent slugs. You will then simulate
Meiosis in both parents to produce sperm and egg cells. Finally, you will produce an offspring slug and
analyze its genotypes and phenotypes.
Procedure & Results
1. Obtain a set of chromosomes for Daddy Slug ( white).
2. Record the genotypes and phenotypes of Daddy Slug in your table
3. Draw a sketch of Daddy Slug based on his phenotypes (NOTE: when sketching, give females eyelashes
and give males no eyelashes).
4.Cut out Daddy Slug’s chromosomes and simulate meiosis by duplicating the chromosomes, and then
randomly separating the chromosomes into 4 “sperm cells.” (each cell gets 1 of each chromosome)
5.Check your sperm cells with your teacher, and then randomly choose one sperm cell to work with and
discard the other one. Enter the alleles in the Daddy Slug sperm into the table.
Table 1: Daddy Slug Genotypes and Phenotypes
3. Sketch of Daddy:
Trait
2.Genotype 2.Phenotype
Eye Shape
Body Pattern
Teeth
Gender
5. Daddy
sperm Cell
Alleles
6. Obtain a set of chromosomes (orange) for Mama Slug.
7. Record the genotypes and phenotypes of Mama Slug in your table
8. Draw a sketch of Mama Slug based on her phenotypes.
9. 4.Cut out Mamma Slug’s chromosomes and simulate meiosis by duplicating the chromosomes, and then
randomly separating the chromosomes into 4 “egg cells.” (each cell gets 1 of each chromosome)
10. Randomly choose one egg cell to work with and discard the other one.
11. Write the alleles in the Mama Slug egg into the table.
Table 2: Mama Slug Genotypes and Phenotypes
8. Sketch of Mama:
Trait
7. Genotype
7. Phenotype
11. Mama
Egg Cell
Allele
Eye Shape
Body Pattern
Teeth
Gender
12. Time for the slugs to reproduce! Have the sperm cell fertilize the egg cell by put the chromosomes
from the sperm and egg cells together.
13. Record the genotypes( alleles) and phenotypes of Baby Slug in your table
14. Draw a sketch of Baby Slug based on his/her phenotypes.
Table 3: Baby Slug Genotypes and Phenotypes
13.
13.
Trait
Allele
Allele 13.
13.
from
from
Genotype Phenotype
Daddy Mama
Eye Shape
14. Sketch of Baby:
Body Pattern
Teeth
Gender
Analysis Questions
Please answer these questions fully and thoughtfully after completing the activity.
1. How many copies of each chromosomes does Daddy Slug have?_____
2. How many copies of each chromosome are in a sperm cell?_____
3. How it is possible for two Round-Eyed parent slugs to have a Star-Eyed baby? Explain using parental
genotypes in your answer.
4. If these slugs had another baby, it would look different. Explain why.
7. In this activity, you used a simplified version of Meiosis. Describe two ways in which the real process of
Meiosis is different from the one you used here.