Genetics
14a - recognize that offspring can resemble parents in inherited traits and learned behaviors (GPS)
14b - discuss what a gene is and the role genes play in the transfer of traits (GPS)
14c - explain the role of chromosomes in development
Background Information:
Cells make up the tissues in the human body. Inside each cell is a nucleus that controls the cell and
contains genetic information on structures called chromosomes. Humans have 46 chromosomes, or 23
pairs, in each of their body cells. The chromosomes are made of thousands of genes (over 60,000).
Each parent contributes half of each chromosome pair to their offspring. Genes give humans their
physical traits (Phenotype) and come in pairs (Genotype). Half of the pair comes from the mother,
while the other half comes from the father. Genes are inherited, and there are different forms called
alleles. Some genes are dominant or stronger and will appear more often. Others are recessive or
hidden and will appear less often. Dominant genes are always represented by a capital letter.
Recessive genes are always represented by a lower-case letter. If an organism has two copies of the
same allele, then the organism is homozygous (home-same, zygous-genes) for that trait (AA, aa). If an
organism has two different alleles (Bb), then it is heterozygous (hetero-different, zygous-genes).
Read The Very Ugly Bug by Liz Pichon. Discuss different traits of the bugs in the story. Create a chart
similar to the one below.
Bug types:
1.
2.
3.
4.
eyes
head
Ugly bug
Green skinny bug
Blue striped bug
Red polka dot bug
The genetics of different bugs in the story:
Genotype
Phenotype
EE or Ee
Tiny Eyes
ee
Big, Googly Eyes
HH or Hh
Smooth, Steady Head
hh
Lumpy, Wobbly Head
BB or Bb
No Hair, Smooth Back
bb
Hairy Back
LL or Ll
No Spotted Legs
ll
Spotted Legs
WW or Ww
No Wings
ww
Fluttery Wings
body
legs
Wings
Using the table above, identify the traits of The Very Ugly Bug.
Dominant Allele
Recessive Allele
Identify the characters’ traits:
Dominant
Character
Trait
Allele
Red Bug
Tiny eyes
Green Bug
Smooth back
Blue Bug
Fluttery wings
Recessive
Allele
Genotype (allele pair)
Genotype
Phenotype (physical trait)
Phenotype
Homozygous or
Heterozygous?
Create your own Very Ugly Bug using the alleles attached.
 Cut out all 28 chromosomes (2 sets of 14) on the lines and place each pair face down, hiding the
letters. These are the chromosomes from the parents.
 Group same size Chromosomes together – both pink and blue.
 Select one set of same size alleles together, one blue (father) and one pink (mother), face-down.
 Turn over the new blue/pink pairs to reveal the genotype and phenotype. These are the alleles
for your offspring. There should be 7 sets.
Using the table below as a guide, construct a species of a very ugly bug with a Styrofoam ball, colored
construction paper, chenille stems, pins, and glue. Your construction paper “baby” bug should
accurately portray your description.
Genotype
EE or Ee
ee
HH or Hh
hh
BB or Bb
bb
SS or Ss
ss
WW or Ww
ww
AA or Aa
aa
LL or Ll
ll
Phenotype
Tiny Eyes
Big, Googly Eyes
Smooth, Steady Head
Lumpy, Wobbly Head
No Hair, Smooth Back
Hairy Back
No Spotted Legs
Spotted Legs
No Wings
Fluttery Wings
Long Antennae
Short Antennae
Long Legs
Short Legs
Which of your “created” bug’s traits are heterozygous? Which are homozygous?
List the pairs of alleles below.
Heterozygous
Homozygous
Describe the genotype and phenotype of your “created” bug.
Genotype
Phenotype
Are there any baby bugs around the classroom that are identical?
Pretend all the baby bugs are set free into open land with plenty of food to eat. However, there are
predators that can see BIG eyes really well. Explain what you think might happen to the baby bugs with
BIG eyes?
Questions:
What is the Phenotype for Bb when b=hairy back and B=no hair on back?
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What is a phenotype? What is a genotype?
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When does a phenotype for a recessive trait appear in an organism?
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W=no wings and w=wings, what is the phenotype for Ww?
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W=no wings and w=wings, what is the phenotype for ww?
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W=no wings and w=wings, what is the phenotype for WW?
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L=long legs and l=short legs, what is the genotype for a bug with short legs?
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L=long legs and l=short legs, what is the genotype for a bug with long legs?
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A=long antennae and a=short antennae, what is the genotype for a homozygous bug with long
antennae?
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A=long antennae and a=short antennae, what is the genotype for a homozygous bug with short
antennae?
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A=long antennae and a=short antennae, what is the genotype for a heterozygous bug with short
antennae?
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Parent Chromosomes – Allele Pairs
Father – Blue
Mother - Pink
A a
B
b
E
e
H h
L
l
S
s
W w