Cats and You: DNA Doubles?
Background: Students will discover the history of the mapping of the human genome
and the feline genome and will compare the number of chromosomes and the DNA for
each.
Goal: Students will discover that feline DNA has many similarities to human DNA.
Objectives: Students will
 Compare and contrast human and cat characteristics
 Read articles explaining the history of the human and feline genome mapping
and view charts comparing chromosomes numbers.
 Answer questions based on initial understanding and persuasive
comprehension
Materials (for a class of 30):
 Large Venn diagram (on white board or easel paper)
 Markers
 15 Copies of Chromosome Numbers Student Sheet
 15 Copies of Chromosome Numbers Chart
 Overhead transparency of Human and Cat Chromosome Comparison
 15 Copies of Human and Feline Genome Decoding Packet
 15 Copies of Cats and You data table and question
 Optional- Internet Access to view Human Chromosome Map and Chromosome
Comparison
http://www.ornl.gov/sci/techresources/Human_Genome/posters/chromosome/chooser.shtml
http://www.sciencemag.org/feature/data/genome99/text/cat.dtl
Time Required: 45 – 60 minute class period
Standards Met:
 Life Science Standards: Structure & function in living systems
 Life Science Standards: Diversity & adaptations of organisms
 Science and Technology Standards: Understanding about science & technology
Procedure:
 Begin by telling the students that you saw a cute cat mentioned in the classifieds
and you thought that it was a great tie in to yesterday’s lesson. Read them the
ad.
 Tell them that you called the number and that you received information about
the cat, Sparky and the shelter said they would fax it to you by tomorrow.
Copyright ©
2009 Pfizer Inc. All rights reserved.
2.1

Pondering Sparky got you to wondering what the genetic similarities might be
between humans and cats.
 Initiation: Ask the class if any students have cats as pets. Have them share
stories about these feline pets. Discuss if cats make good pets. (34% of the
American population has a pet cat)
 Ask the class to compare humans and cats. What are their similarities and
differences?
 As a class, create a Venn diagram comparing human and cat characteristics. (if
preferred, each student or student group could do this on their own and then
one large diagram could be created from their ideas)
 Pass out the Chromosome Number Student Sheet and give students time to
answer questions
 Give students Chromosome Number Chart. Have them complete and discuss
their answers to questions #6 and 7.
 Put transparency of Cat and Human Chromosome Comparisons on overhead.
Have students compare their answers to questions 1 and 2 to actuals.
DAY 2
 Pass out the History of Human and Cat Genome mapping sheets.
 Each student reads the Genome information and fills in their data table and
answers a persuasive question.
 Collect the papers to correct later (use rubric to score persuasive question)
 Review the answers with the class.
 If time permits, conduct a class debate involving the final question.
*If you have access to computers, simply have student complete the research on-line,
instead of making copies!
http://www.sciencemag.org/feature/data/genome99/text/cat.dtl (to see genome map
of cat and human)
http://www.ornl.gov/sci/techresources/Human_Genome/posters/chromosome/choose
r.shtml (to see human genome)
Assessment:
Participation in class discussion and completion of Venn diagram
 Completion of Chromosome Number Student Sheet
Completion of Genome data table
 Scoring of persuasive question
Copyright ©
2009 Pfizer Inc. All rights reserved.
2.2
Cats and You: DNA Doubles?
Chromosome Numbers Student Sheet
Directions: Work with a partner to hypothesize answers to the following questions:
1. How many chromosomes do humans have? _____________________
2. How many chromosomes do cats have? ______________________
3. How many chromosomes do algae have? _____________________
4. How many chromosomes do elephants have? __________________
5. Describe the relationship between the number of chromosomes an organism has
and its:

Size _____________________________________________________________

Intelligence _______________________________________________________

Lifespan _________________________________________________________
6. Looking at the Chromosome Numbers Chart, what surprises you about the numbers?
Do you notice any patterns about the various species?
7. Evaluate if you need to change your answers to questions #1-2. Give a 2 sentence
rationale explaining why you changed or kept your answers.
Copyright ©
2009 Pfizer Inc. All rights reserved.
2.3
Cats and You: DNA Doubles?
Chromosome Numbers Teacher Key
Directions: Work with a partner to hypothesize answers to the following questions:
1. How many chromosomes do humans have? 46
2. How many chromosomes do cats have? 38
3. How many chromosomes do algae have? 148
4. How many chromosomes do elephants have? 56
5. Describe the relationship between the number of chromosomes an organism has
and its:
(there is no relationship for the following factors)
 Size _____________________________________________________________

Intelligence _______________________________________________________

Lifespan _________________________________________________________
6. Looking at the Chromosome Numbers Chart, what surprises you about the numbers?
Do you notice any patterns about the various species?
Answers will vary, but could include:
A shrimp has 254 chromosomes and a wooly mammoth only has 58! Both insects on
the chart have fewer than 10 chromosomes. There doesn’t seem to be a relationship
between organism complexity and the number of chromosomes.
7. Evaluate if you need to change your answers to questions #1-2. Give a 2 sentence
rationale explaining why you changed or kept your answers.
Answers will vary, but could include:
A rabbit seems similar to a cat so I think a cat will have around 44 chromosomes.
A chimpanzee has 48, and my teacher tells me that chimps and humans are alike.
Copyright ©
2009 Pfizer Inc. All rights reserved.
2.4
Cats and You: DNA Doubles?
Chromosome Numbers Chart
Organism
Number of Chromosomes
Algae
148
Carp (fish)
104
Chicken
78
Chimpanzee
48
Cotton
26
Cow
60
Coyote
78
Drosophila melanogaster (fruit fly) 8
Duck-billed Platypus
52
Earthworm
36
Elephant
56
Giraffe
62
Gorilla
48
Horse
64
Kangaroo
12
Mango
40
Mosquito
6
Mouse
40
Orangutan
48
Pig
38
Pigeon
80
Potato
48
Rabbit
44
Raccoon
38
Rat
42
Sheep
54
Shrimp
254
Snail
24
Starfish
36
Tiger
38
Wheat
42
Copyright ©
2009 Pfizer Inc. All rights reserved.
2.5
Cats and You: DNA Doubles?
Cat and Human Chromosome Comparisons
CAT CHROMOSOMES
19
Copyright ©
2009 Pfizer Inc. All rights reserved.
2.6
Cats and You: DNA Doubles?
The Human Genome Project Completion:
On April 14, 2003 the National Human Genome Research Institute (NHGRI),
the Department of Energy (DOE) and their partners in the International
Human Genome Sequencing Consortium announced the successful
completion of the Human Genome Project.
What is a genome?
A genome is an organism's complete set of deoxyribonucleic acid (DNA), a chemical
compound that contains the genetic instructions needed to develop and direct the
activities of every organism. DNA molecules are made of two twisting, paired strands.
Each strand is made of four chemical units, called nucleotide bases. The bases are
adenine (A), thymine (T), guanine (G) and cytosine (C). Bases on opposite strands pair
specifically; an A always pairs with a T, and a C always with a G.
The human genome contains approximately 3 billion of these base pairs, which reside in
the 23 pairs of chromosomes within the nucleus of all our cells. Each chromosome
contains hundreds to thousands of genes, which carry the instructions for making
proteins. Each of the estimated 30,000 genes in the human genome makes an average
of three proteins.
What Does the Draft Human Genome Sequence Tell Us?
By the Numbers

The human genome contains 3.1647 billion bases

The average gene consists of 3000 bases, but sizes vary greatly.

The total number of genes is estimated at 30,000

Almost all (99.9%) bases are exactly the same in all people.

The functions are unknown for over 50% of discovered genes.
Copyright ©
2009 Pfizer Inc. All rights reserved.
2.7
Is the human genome completely sequenced?
Yes - within the limits of today's technology, the human genome is as complete as it can
be.
The gene-containing portion of the genome is complete in nearly every functional way
for the purposes of scientific research and is freely and publicly available. Even though
the Human Genome Project is now completed, scientists will continue to develop and
apply new technologies. For its part, NHGRI will continue to support a wide range of
research to develop new sequencing technologies, to interpret the human sequence
and to use the newfound understanding of the human genome to improve human
health.
Whose DNA was sequenced for the Human Genome Project?
This is intentionally not known to protect the volunteers who provided DNA samples for sequencing. The
sequence is derived from the DNA of several volunteers. To ensure that the identities of the volunteers
cannot be revealed, a careful process was developed to recruit the volunteers and to collect and maintain
the blood samples that were the source of the DNA.
Applications, Future Challenges
Deriving meaningful knowledge from the DNA sequence will define research through
the coming decades to inform our understanding of biological systems. This enormous
task will require the expertise and creativity of tens of thousands of scientists from
varied disciplines in both the public and private sectors worldwide.
The draft sequence already is having an impact on finding genes associated with
disease. A number of genes have been pinpointed and associated with breast cancer,
muscle disease, deafness, and blindness. Additionally, finding the DNA sequences
underlying such common diseases as cardiovascular disease, diabetes, arthritis, and
cancers is being aided by the human variation maps (SNPs) generated in the HGP in
cooperation with the private sector. These genes and SNPs provide focused targets for
the development of effective new therapies.
One of the greatest impacts of having the sequence may well be in enabling an entirely
new approach to biological research. In the past, researchers studied one or a few genes
at a time. With whole-genome sequences and new high-throughput technologies, they
can approach questions systematically and on a grand scale. They can study all the
genes in a genome, for example, or all the transcripts in a particular tissue or organ or
tumor, or how tens of thousands of genes and proteins work together in interconnected
networks to orchestrate the chemistry of life.
Copyright ©
2009 Pfizer Inc. All rights reserved.
2.8
Cats and You: DNA Doubles?
Domestic Cat Genome Sequenced
ScienceDaily (Nov. 1, 2007) —
Of all of the cats in the world, Cinnamon was
chosen to be the definitive genetic model for
all cats in a project called the feline genome
project. By donating a small vial of blood,
Cinnamon provided scientists the
wherewithal to map the feline genetic
structure, eventually allowing for each gene's
function to be noted and studied. (Credit:
University of Missouri College of Veterinary
Medicine)
The DNA of a 4-year-old Abyssinian cat named Cinnamon, whose well-documented
lineage can be traced back several generations to Sweden, has been sequenced.
Cinnamon is one of several mammals that are currently being analyzed using "light"
genome sequence coverage.
The similarity between the cat genome and six recently completed mammalian
genomes (human, chimpanzee, mouse, rat, dog, and cow) allowed the scientists to
identify 20,285 genes in the cat genome. The comparison also revealed hundreds of
chromosomal rearrangements that have occurred among the different lineages of
mammals since they diverged from ancestors that roamed the earth among the
dinosaurs some 100 million years ago.
The genome sequence analysis is certainly expected to lead to health benefits for
domestic cats, 90 million of which are owned by Americans alone, according to The
Humane Society. But the domestic cat also serves as an excellent model for human
disease, which is one reason why the National Human Genome Research Institute
(NHGRI) initially authorized the cat genome sequencing project three years ago.
Domestic cats possess over 250 naturally occurring hereditary disorders, many of which
are similar to genetic pathologies in humans. For example, Cinnamon's pedigree carries
a genetic mutation that causes retinitis pigmentosa, a degenerative eye disease that can
lead to blindness. In humans, retinitis pigmentosa affects 1 in 3,500 Americans. The
domestic cat also serves as an excellent model for human infectious diseases, including
Copyright ©
2009 Pfizer Inc. All rights reserved.
2.9
HIV/AIDS. Feline immunodeficiency virus (FIV) is a genetic relative of human
immunodeficiency virus (HIV), which causes AIDS.
Using the cat genome sequence data, the researchers identified several hundred
thousand genomic variants which can be used to determine the genetic basis for
common hereditary diseases. The scientists have already used these variants to identify
the causative gene for Cinnamon's retinitis pigmentosa. These variants will also be
useful for parentage testing, forensic analysis, and studies of evolution, including the
reconstruction of domestication processes, fancy breed development, and ecological
adaptation among the great roaring cats.
About Cinnamon
Cinnamon is a shy cat. While the other cats in Dr. Kristina Narfstrom's ophthalmology
research center at the University of Missouri College of Veterinary Medicine vie for the
attention of veterinary medical students and technicians, Cinnamon is more reticent,
preferring to sit quietly and watch the other cats play and carouse.
Future research
Dr. Narfstrom predicts that the feline genome will rapidly shed new research light on a
number of cat and human medical problems including virus-mediated diseases,
respiratory problems, cancers, AIDS, immunity problems, muscular dystrophy, polycystic
kidney disorder, and Dr. Narfstrom's research specialty, retinal eye diseases. Cats and
humans share about 250 genetic diseases.
The Cat Genome Project is based at the National Cancer Institute (Frederick, Md.).
Cinnamon lives in a cat colony maintained at the University of Missouri-Columbia. The
sequencing data were generated by Agencourt Bioscience Corporation (Beverly, Mass.).
A report that appears in the scientific journal Genome Research details the first
assembly, annotation, and comparative analysis of the domestic cat genome (Felis
catus).
Adapted from materials provided by Cold Spring Harbor Laboratory, via EurekAlert!, a service of AAAS.
Copyright ©
2009 Pfizer Inc. All rights reserved.
2.10
Cats and You: DNA Doubles?
Question
Human
Cat
How many chromosomes
does each mammal have?
How many genes does each
mammal have?
What year was the genome
sequenced?
Where did the DNA sample
come from?
What is a benefit to
sequencing this animals
DNA?
Decoding the DNA sequence of domestic cats cost an estimated $2.4 million. Was the
expense worth it? Do you think scientists should continue to research the cat DNA?
Why or why not? Support your opinion with facts from the articles and your
knowledge of genetics.
Copyright ©
2009 Pfizer Inc. All rights reserved.
2.11
Cats and You: DNA Doubles?
Vocabulary
Word
Definition
chromosome
A DNA molecule which is
curled around a protein
molecule
genome
An organism’s complete set
of DNA
DNA
(deoxyribonucleic acid)
Drawing
The chemical compounds
that have the genetic codes
for an organism (these
chemicals make you a
human and not a cat!)
gene
An inherited instruction for
a particular characteristic;
it’s a section of DNA
bases
A type of chemical found in
genetic material; there are
4 bases that combine in
millions of ways to make
genes
Copyright ©
2009 Pfizer Inc. All rights reserved.
2.12