Download Reebops Lab

 Reebops Lab
Background:
As you create baby Reebops from
marshmallows and other objects, they
can help you see how the visible traits of a
baby are related to the combination of
genes that it inherited from its mom and
dad, and why all the kids in the family don’t
always look alike.
Each Reebop has 7 pairs of chromosomes for a total of 14 chromosomes.
Half of the chromosomes in a Reebop come from the father, and half come
from the mother. Reebops have only one or two genes in each chromosome
(humans on the other hand may have hundreds or thousands of genes on each
chromosome!) Genes are segments of a chromosome that code for a trait,
for example; in Reebops there is a gene for eye color. There can be more
than one allele at each gene; an allele is a version of the gene. There are two
alleles for eye color in Reebops, E is the allele for red eye and e is the allele
for green eyes. In this case E is dominant to e. The term genotype
describes the combination of alleles that an organism has. The term
phenotype describes what an organism looks like.
Purpose:
1. To understand the relationship between alleles, genes, and
chromosomes.
2. To understand how genes and traits are inherited.
3. To construct Punnett Squares
Materials: A set of 14 chromosomes (7 pink ones for the mother and 7 blue
ones for the father.) Materials to construct baby Reebops.
Procedure:
1. Look at the Mother and Father Reebops. Describe their traits, how
are they similar, how are they different?
2. Lay out the chromosomes upside down. Separate the chromosomes
into mother (pink) and father (blue) chromosomes. For each of the
colors, organize the chromosomes from longest to shortest. For each
parent there are two chromosomes of each length. Take ONE
chromosome of each length from each parent. You should have one
pink and one blue chromosomes of each length. These are now your
baby Reebop’s chromosomes.
3. Next, flip the chromosomes over so you can see the letter(s). Each
letter is an allele. Record these alleles in the table on the next page.
For each trait, the baby’s genotype is the allele from the mother plus
the allele from the father (one pink and one blue).
4. Use the baby’s genotype and the chart below to determine your baby
Reebop’s phenotype. Record these in the table on the next page also.
Phenotype Chart
Antenna
AA = 2 antennae
Aa = 1 antenna
aa = no antennae
Leg Color
LL = blue legs
Ll = blue legs
ll = red legs
Nose Color
NN = yellow nose
Nn = yellow nose
nn = green nose
Number of Humps
HH = 1 hump
Hh = 2 humps
hh = 3 humps
Body Segments
BB = 3 segments
Bb = 3 segments
bb = 2 segments
Tail
TT = curly tail
Tt = curly tail
tt = straight tail
Eye Color
EE = red eyes
Ee = red eyes
er = green eyes
Sex
XX = female
XY = male
YX = male
5. Draw your Reebop based on the phenotype. Remember to use color.
6. Next you get to construct your baby Reebop. Your teacher will provide
you with the materials.
Observations:
Mother’s Allele
Antenna
Baby’s Phenotype is:
Nose color
Baby’s Phenotype is:
Eyes
Baby’s Phenotype is:
Body Segments
Baby’s Phenotype is:
Humps
Baby’s Phenotype is:
Tail
Baby’s Phenotype is:
Leg color
Baby’s Phenotype is:
Sex
Baby’s Phenotype is:
Father’s Allele
When you are finished determining your baby’s phenotype draw and color
your baby Reebop in the space below:
Circle one: Male Female
Baby’s name
Baby’s Birth date
Analysis:
1. When every one is finished creating their Reebops, compare them. Do
they all look the same?
2. What are some differences? (Give at least 2 examples)
3. All of the baby Reebops came from the same two parents. The
parents are both heterozygous for all the traits except body
segments. Explain why the babies don’t all look the same? Use a
Punnett square to support your answer.
4. What is the probability that a baby Reebop will have red legs? Give
both the fraction and the percentage. Include a Punnett Square.
5. How is it possible for 2 babies to have different genotypes, but still
look the same?
6. Which two traits in Reebops are controlled by incomplete dominance?
How do you know?
7. Why are the only Reebops with 3 segments Boys?
8. If a Reebop female with a green nose and a Reebop male with a yellow
nose (heterozygous) marry and have children, what genotype and
phenotype for nose color will their children have? Include a Punnett
Square.
9. If a Reebop female with one antenna and a Reebop male with one
antenna marry and have children, what is the probability that they will
have a baby with no antenna? Include a Punnett Square.
10. If a Reebop baby has a straight tail, but both parents have a curly
tail, what are the genotypes of the two parents? Include a Punnett
Square