Name:____________________________
Date:_____________________
Period:_________
Inquiry Lab: DNA Sequencing and Your Traits KEY
Part I – “Decoding Your DNA”
Directions: Read the Science World article titled “Decoding Your DNA.” Decide
who will read each section aloud and write his/her name on the line. Answer
the questions after each section.
Name of Reader: ____________________ Read aloud the INTRODUCTION
1. How is the human genome like a personal instruction manual?
The genome carries the directions for everything about you (eye color, blood type, etc.)
Name of Reader: ____________________ Read aloud the section “Cracking the Code”
2. How do nitrogen bases pair together?
Adenine (A)-- Thymine (T)
Guanine (G)—Cytosine(C)
3. What does it mean to SEQUENCE a person’s genetic code?
Sequencing means to figure out the order of the 3 billion bases along one of the strands.
4. Write the meaning of each word based on what you just read.
a. Gene – A DNA sequence that carries the directions to make proteins
b. Protein – help a cell function and determine a person’s traits
c. Mutation – a mistake or “error” in the DNA sequence
5. Analyze the picture textbox “Genes and Diseases.” What are “spelling mistakes” and how
can they affect a person?
“Spelling mistakes” are errors/mutations in a DNA sequence. These can lead to diseases in
human. Scientists have already discovered 6,000 diseases caused by these mistakes.
6. Analyze the picture on page 21. How are chromosomes, DNA, and genes RELATED?
Chromosomes are made of tightly coiled DNA. On this DNA are important sequences called
genes. These genes code for proteins.
Lab
Name:____________________________
Date:_____________________
Period:_________
Name of Reader: ____________________ Read aloud the section “Cheaper and Faster”
7. How much would it cost to have your genome sequenced? $1000
Name of Reader: ____________________ Read aloud the section “How Sequencing Works”
8. How is the method of sequencing DNA similar to doing a giant jigsaw puzzle?
To sequence DNA, scientists must separate the strands and then cut them into pieces
(fragments). After a microchip and computer figure out the order of the bases, the pieces
must be put back together like a puzzle.
Name of Reader: ____________________ Read aloud the section “Tailored Medicine”
9. How can DNA sequencing help a person? Give 3 reasons from the article.
a. Doctors could learn what diseases a patient might get ahead of time.
b. Doctors could screen patients and let them know what diseases they could pass to
their children.
c. Doctors could figure out the best prescriptions to give a patient (tailored medicine)
d. of Reader: ____________________ Read aloud the section “Risks vs. Benefits”
Name
10. How could a person’s genetic information be used against him or her? Explain.
A person might be denied health insurance or be fired from a job. These companies see the
person as a health risk because their DNA shows potential disease genes.
11. OPINION – Would you have your DNA sequenced? Why or why not?
Answers will vary.
Name of Reader: ____________________ Analyze the Graph in the box titled “Size Comparison”
12. How many bases is each organism’s genome?
a. Human- 3 billion
b. Chicken – a little over 1 billion c. Fruit fly – 0.25 billion
Lab
Name:____________________________
Date:_____________________
Period:_________
Part II– Simulate Sequencing and Analysis of Genes (READ & HIGHLIGHT)
Three sisters want to have their DNA sequenced because there is a strong history of breast cancer in the family.
Therefore, the women would like to know their risk of developing this disease.
Upon entering the office, the genetic counselor explains that DNA will be taken from cheek cells and sequenced
using a high-tech sequencer like the one discussed in the article above. Afterwards, a small segment of DNA will
be analyzed. He calls this small segment of DNA which codes for an observable trait a GENE. He explains that
there are 3 possible GENES that that can be inherited:

AATTCCGGCCGGATATCAGA - NORMAL/HEALTHY GENE

AATTCCGGCCGGTATTGACA -BRCA1 GENE Having this sequence increases a female’s chance of
developing breast cancer but does NOT make it certain

AATTCCGGCCCCCCTCAGAA – BRCA2 GENE Having this sequence increases a female’s chance of
developing breast cancer but does NOT make it certain.
Directions:
1. For each sister, only ONE side of her DNA ladder is shown. Using the base pairing rule fill in
the sequence on the other side of the ladder(A with T; G with C).
2. Analyze the sequence you just wrote. Match this order with one of the genes listed above.
Sister #1
TTAAGGCCGGCCATAACTGT
What gene does sister #1 have?
AATTCCGGCCGGTATTGACA
BRCA 1 gene
Sister #2
TTAAGGCCGGCCTATAGTCT
What gene does sister #2 have?
AATTCCGGCCGGATATCAGA
Normal/Healthy Gene
Sister #3
TTAAGGCCGGGGGGAGTCTT
What gene does sister #3 have?
AATTCCGGCCCCCCTCAGAA
BRCA 2 gene
3. Compare the sequence of the NORMAL gene to that of each breast cancer gene. How many
“spelling mistakes” or base differences are there for each gene?
a. Figure out how many “spelling mistakes” are in the BRCA1 gene. 5
b. Figure out how many “spelling mistakes” are in the BRCA2 gene. 9
See your teacher for an answer key.
Lab
Name:____________________________
Date:_____________________
Period:_________
Part III– From Genes to Traits (READ & HIGHLIGHT)
Humans are not the only organisms that can have their DNA sequenced. Any living thing can have their DNA
sequenced. Even your dog can have his/her DNA sequenced! In this part of the lab you will examine the DNA
sequence of 3 dogs. You job is to analyze the genes of the dogs and determine what traits the organism has.
Below are the DNA molecules of three dogs. Each DNA molecule has 4 genes separated by bold-faced lines.
Remember each GENE is a WORD that the ribosome can read! The ribosome reads this word and creates a
protein.
Directions:
1. One person should act as the ribosome and read each gene sequence ALOUD.
2. A second person should use the chart on the next page to determine what protein is made.
3. All group members should write the protein on the line underneath the DNA sequence.
4. After you are done, draw the dog with its traits coloring only where needed.
DOG #1
A C C G G T T A T
|
Brown fur
A G G G G A G G G
|
Short, droopy ears
T T T G G G A A A
|
Small, black spots
G G A C G C C G A
|
Long, curly tail
DOG #2
A C C G G T C C C
|
Golden fur
A G C C G A G G G
|
Long, droopy ears
T T T A A C A A A
|
Big, black spots
G G A C A A A G A
|
Long, wavy tail
DOG #3
A A C G G T T A T
Black fur
DOG #1
|
A G C C G A C C C
Pointy ears
|
T T T A A C T T T
|
No spots
DOG #2
See your teacher for an answer key.
G G T A C C C G A
|
Long, straight tail
DOG #3
Lab
Name:____________________________
Date:_____________________
Period:_________
DNA AND TRAITS CHART
DNA sequence
Protein Made
GENE 1
A C C G G T T A T
Protein for brown fur
A A C G G T T A T
Protein for black fur
A C C G G T C C C
Protein for golden fur
GENE 2
A G C C G A G G G
Protein for long, droopy ears
A G G G G A G G G
Protein for short, droopy ears
A G C C G A C C C
Protein for pointy ears (upright)
GENE 3
T T T G G G A A A
Protein for SMALL black spots
T T T A A C A A A
Protein for BIG black spots
T T T A A C T T T
Protein for NO spots
GENE 4
G G T A C C C G A
Protein for long, straight Tail
G G A C G C C G A
Protein for long, curly Tail
G G A C A A A G A
Protein for long, wavy tail
Part IV– Wrapping it up with a Quick Assessment!
Directions: Read each statement and fill in the correct word.
1. DNA is made up of 4 BASES. These include: adenine, thymine, guanine, and cytosine.
2. When these bases are in a certain order, they create a “word” which scientists call a GENE.
3. These genes are read by the RIBOSOME to create a protein.
4. The protein will give an organism an observable characteristic known as a TRAIT.
5. Look at the picture to the right.
a. Which label is indicating a gene? Label B
A
b. Which label is indicating a chromosome? Label A
See your teacher for an answer key.
Lab
B