Download Rebop Lab 2007 rebop_lab_2007

Reebops!
Materials:
Big white marshmallows – for body
Little colored marshmallows - for humps and noses
Colored Tooth picks - for legs and antenna
Unbent small paper clips or pipe cleaners - for tails
Thumbtacks or push pins - for eyes
--Plain toothpicks hold the head on, and the body together
Reebops (Reebopins minimus) are small organisms that live in empty pop cans. Chances are you have
never seen one as they are extremely fast little organisms! Chromosomal analysis has revealed that
each Reebop has 8 pairs of chromosomes for a total of 16 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 on
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 a gene. There are
two alleles for number of eyes in Reebops, E is the allele for two eyes and e is the allele for three 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.
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 2 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 page 2. 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 page 2.
Phenotype
1 antenna
2 antenna
No antenna
Red nose
Orange nose
Yellow nose
2 eyes
3 eyes
3 body segments
2 body segments
1 green hump
2 green humps
3 green humps
Curly tail
Zig-Zag tail
Straight tail
Blue legs
Purple Legs
red legs
Female
Male
Genotype
AA
Aa
aa
QQ
Qq
qq
EE or Ee
ee
DD or Dd
dd
MM
Mm
mm
TT
Tt
tt
LL
Ll
ll
XX
XY
Reebop Breeding Day!
Name________
Antenna
_______ Date __________ Period _____
Mother’s Allele
______________
Father’s Allele
_____________
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:________________________
Your Baby’s Name
_________________________
Your Baby’s Birth date
___________
_
Remember that the genotype is represented by letters and the Phenotype is
what it looks like (eg. Red nose).
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, why don’t they all look the same?
4. What is the probability that a baby Reebop will have red legs? Give both the fraction and the
percentage. Hint: Do a punnet square.
5. What is the probability that a baby Reebop will have a curly tail? Give both the fraction and the
percentage.
6. How is it possible for 2 babies to have different genotypes, but still look the same?
7. Which two traits in Reebops are controlled by incomplete dominance? (You will not be able to
tell by looking for 2 different letters for the same trait.) How do you know?