Objective: Determine the identity of the Mystery Donor
Snapshot of Procedure
1. Read the Summary of Evidence Report
2. Determine genotype of hand print left at the courthouse by
completing the ‘Differences in Similar Phenotypes’ HOT Lab.
3. Read ‘The Genetics of Eye Color’ article to determine the probable
eye color of mystery donor.
4. ‘Can Chromosomal Abnormalities Be Observed?’ – HOT lab (look
at Figures 1, 4 and 5)
5. Then complete the karyotype analysis of the mystery donor and
compare to the provided karyotypes.
6. Identify the donor with explanation on how you came to your
conclusion.
Summary of Evidence Report
Forensic Files
November 2, 2011
Generous Donor
Unusual Day at
Courthouse




Volume 1, Issue 1
Unknown donor
leaves winning
lottery ticket for
homeless animals.
Ticket invalid
without donor
signature.
Palm print found on
letter.
Blood droplet allows
karyotyping.
Inside this issue:

Custodian Does the
Right Thing
2

Karyotyping
The chatter in the courtroom
was constant.
Discussion
pursued,
offering
varying
hypotheses as to the identity
of the ticket owner. Just that
morning, the custodian had
found an envelope taped to
the door of the Port Jefferson
Court House. The letter inside
read,
“I have been given many
gifts in my life. But yesterday I
was given an unusual gift –
that of winning the lottery.
After many hours of
contemplation, I decided that I
did not want to keep
New York. As a courtesy, the
finder of this ticket should
receive a ‘finders-fee’ equal to
10% of proceeds.”
The problem was that by the
New York state law, there had
to be a signature or the letter
was not legal. The case was
put in front of the judge for
legal direction. She declared
that forensics could be used to
track down the donor.
2

The Genetics of Eye
Color
3
Palm Print May Lead to
Donor’s Identity
After hours of evidence
collection,
forensic
investigators finally released
the information on the
evidence collected.
A palm print was found on the
letter itself. It measured 20
cm. in length and 11.5 cm.
wide. It was found that the
donor has a combination of
bbGG alleles for eye color.
Additional information was
obtained from a drop of blood
found on the edge of the letter.
Tapes from the security
cameras are being reviewed.
Preliminary results show that
four people were on the
courthouse grounds between
12 midnight and 8:00 AM.
Officials would like to speak
with these individuals.
Differences in Similar Phenotypes
NGSSS:
SC.912.L.16.1 Use Mendel’s Laws of Segregation and Independent Assortment to analyze
patterns of inheritance. AA
SC.912.L.16.2 Discuss observed inheritance patterns caused by various modes of inheritance,
including dominant, recessive, co-dominant, sex-linked, polygenic, and multiple alleles.
Background:
Humans are classified as a separate species because of all the special characteristics that they
possess. These characteristics are controlled by strands of DNA located deep inside their cells.
This DNA contains the code for every protein that an organism has the ability to produce.
These proteins combine with other chemicals within the body to produce the cells, tissues,
organs, organ systems, and finally the organism itself. The appearance of these organs, such as
the shape of one’s nose, length of the fingers, or the color of the eyes is called the phenotype.
Even though humans contain hands with five fingers, two ears, or one nose, there are subtle
differences that separate these organs from one another. There are subtle differences in a
person’s genes that allows for these different phenotypes. In this lab, we are going to observe
some of these differences in phenotype and try to determine why they happened.
Problem Statement: Do all human hands measure the same?
Vocabulary: alleles, dominant, genotype, homozygous, heterozygous (hybrid), phenotype,
recessive
Materials (per group):
 Metric ruler
 Meter stick
Procedures:
Hand Measurement:
All human hands look pretty much alike. There are genes on your chromosomes that code for
the characteristics making up your hand. We are going to examine two of these characteristics:
hand width and hand length.
1. Choose a partner and, with a metric ruler, measure the length of their right hand in
centimeters, rounding off to the nearest whole centimeter. Measure from the tip of the
middle finger to the beginning of the wrist. Now have your partner do the same to you.
Record your measurements in Table 1.
2. Have your partner measure the width of your hand, straight across the palm, and record
the data in Table 1. Have your partner do the same to you.
Table 1 - Group Data on Right Hand Width and Length
Name:
____________________________
Name:
____________________________
Length of Hand
___________________cm.
Length of Hand
____________________cm.
Width of Hand
____________________cm.
Width of hand
_____________________cm.
Class Data: After the entire class has completed Table 1, have the students record their data on
the board in the front of the room. Use Table 2 below to record the data for your use. Extend
the table on another sheet of paper if needed.
Table 2 - Class Data on Right- Hand Width and Length
Student
Gender
M/F
Hand Length (cm)
Hand Width (cm)
M/F
M/F
M/F
M/F
M/F
M/F
M/F
M/F
M/F
M/F
M/F
Tabulate the results of your class measurements by totaling the number of males and females
with each hand length and width and entering these totals in the tables below.
Table 3 - Class Hand Length
Measurement of Hand
Length in cm.
# of Males
# of Females
Total No. of Males
and Females
Table 4 - Class Hand Width
Measurement of Hand
Length in cm.
# of Males
# of Females
Total No. of Males
and Females
In order to form a more accurate conclusion, the collection of additional data is necessary. The
teacher has the option to include the data from all the classes running this experiment. Below
find tables that will allow the tabulation of several classes of data.
Bar Graph the data from Tables 5 and 6, and then answer the questions that follow. Use the
measurements of the width and length as your independent variable and the number of times
that measurement appeared as your dependent variable.
Graph Title: ___________________________________________________________
Observations/Analysis:
1. Examine the graphs. What is the shape of the graph for hand length? What is the most
abundant measurement for hand length?
2. What is (are) the least abundant measurement(s)?
3. If we are to assign letters to represent the various lengths, what value(s) would we assign
to the dominant genotype (HH)? The recessive genotype (hh)? The heterozygous
genotype (Hh)?
4. What would be the phenotypic name for the (HH) genotype?
5. What would be the phenotypic name for the (Hh) genotype?
6. What would be the phenotypic name for the (hh) genotype?
7. What is the shape of the graph for hand width?
8. What is the most abundant measurement for hand width?
9. What is (are) the least abundant measurement(s)?
10. If we assign letters to represent the various widths, what value(s) would we assign to the
dominant genotype (WW)? The recessive genotype (ww)? The heterozygous genotype
(Ww)?
11. What would be the phenotypic name for the (WW) genotype?
12. What would be the phenotypic name for the (Ww) genotype?
13. What would be the phenotypic name for the (ww) genotype?
14. Are there any similarities in the graphs of the two characteristics? If so, what are they?
15. Are there any differences in the graphs of the two characteristics? If so, what are they?
16. Is there a difference in the length and width of the male and female hand? Does the
gender of a person have an effect on the phenotype of a trait? Explain:
Conclusion:
Develop a written report that summarizes the results of this investigation. Use the analysis
questions as a guide in developing your report. Make sure to give possible explanations for your
findings by making connections to the NGSSS found at the beginning of this lab hand-out. Also,
mention any recommendations for further study in this investigation.
The Genetics of Eye Color
The genetics of blood type is a relatively simple case of one
locus Mendelian genetics—albeit with three alleles segregating
instead of the usual two (Genetics of ABO Blood Types).
Eye color is more complicated because there's more than one
locus that contributes to the color of your eyes. In this posting
the description will entail the basic genetics of eye color based
on two different loci. This is a standard explanation of eye color but, as we'll see later on, it
doesn't explain the whole story. Let's just think of it as a convenient way to introduce the
concept of independent segregation at two loci. Variation in eye color is only significant in
people of European descent.
At one locus (site=gene) there are two different alleles segregating: the B allele confers brown
eye color and the recessive b allele gives rise to blue eye color. At the other locus (gene) there
are also two alleles: G for green or hazel eyes and g for lighter colored eyes.
The B allele will always make brown eyes regardless of what allele is present at the other locus.
In other words, B is dominant over G. In order to have true blue eyes your genotype must be
bbgg. If you are homozygous for the B alleles, your eyes will be darker than if you are
heterozygous and if you are homozygous for the G allele, in the absence of B, then your eyes
will be darker (more hazel) that if you have one one G allele.
Here's the Punnett Square matrix for a cross between two parents who are heterozygous at
both alleles. This covers all the possibilities. In two-factor crosses we need to distinguish
between the alleles at each locus so I've inserted a backslash (/) between the two genes to
make the distinction clear. The alleles at each locus are on separate chromosomes so they
segregate independently.
As with the ABO blood groups, the possibilities along the left-hand side and at the top represent
the genotypes of sperm and eggs. Each of these gamete cells will carry a single copy of the Bb
alleles on one chromosome and a single copy of the Gg alleles on another chromosome.
Since there are four possible genotypes at each locus, there are sixteen possible combinations
of alleles at the two loci combined. All possibilities are equally probable. The tricky part is
determining the phenotype (eye color) for each of the possibilities.
According to the standard explanation, the BBGG genotype will usually result in very dark brown
eyes and the bbgg genotype will usually result in very blue-gray eyes. The combination bbGG
will give rise to very green/hazel eyes. The exact color can vary so that sometimes bbGG
individuals may have brown eyes and sometimes their eyes may look quite blue. (Again, this is
according to the simple two-factor model.)
The relationship between genotype and phenotype is called penetrance. If the genotype always
predicts the exact phenotpye then the penetrance is high. In the case of eye color we see
incomplete penetrance because eye color can vary considerably for a given genotype. There
are two main causes of incomplete penetrance; genetic and environmental. Both of them are
playing a role in eye color. There are other genes that influence the phenotype and the final
color also depends on the environment. (Eye color can change during your lifetime.)
One of the most puzzling aspects of eye color genetics is accounting for the birth of brown-eyed
children to blue-eyed parents. This is a real phenomenon and not just a case of mistaken
fatherhood. Based on the simple two-factor model, we can guess that the parents in this case
are probably bbGg with a shift toward the lighter side of a light hazel eye color. The child is
bbGG where the presence of two G alleles will confer a brown eye color under some
circumstances.
Posted by Larry Moran at 11:30 AM
Labels: Biochemistry, Science Education
http://sandwalk.blogspot.com/2007/02/genetics-of-eye-color.html
Making Karyotypes
(Adapted from: Prentice Hall, Lab Manual A)
NGSSS:
SC.912.L.16.10 Evaluate the impact of biotechnology on the individual, society and the
environment, including medical and ethical issues. AA
HE.912.C.1.4 Analyze how heredity and family history can impact personal health.
(Also addresses SC.912.L.14.6)
Background:
Several human genetic disorders are caused by extra, missing, or damaged chromosomes. In
order to study these disorders, cells from a person are grown with a chemical that stops cell
division at the metaphase stage. During metaphase, a chromosome exists as two chromatids
attached at the centromere. The cells are stained to reveal banding patterns and placed on
glass slides. The chromosomes are observed under the microscope, where they are counted,
checked for abnormalities, and photographed. The photograph is then enlarged, and the images
of the chromosomes are individually cut out. The chromosomes are identified and arranged in
homologous pairs. The arrangement of homologous pairs is called a karyotype. In this
investigation, you will use a sketch of chromosomes to make a karyotype. You will also examine
the karyotype to determine the presence of any chromosomal abnormalities.
Problem Statement: Can chromosomal abnormalities be observed?
Safety: Be careful when handling scissors.
Vocabulary: centromere, chromosomes, chromatids, genes, homologous pairs, karyotype,
mutations, Trisomy 21- Down syndrome, Klinefelter syndrome, Turner syndrome
Materials (per individual):
 Scissors
 Glue or transparent tape
Procedures:
Part A. Analyzing a Karyotype
1. Make a hypothesis based on the problem statement above.
2. Observe the normal human karyotype in Figure 1. Notice that the two sex chromosomes,
pair number 23, do not look alike. They are different because this karyotype is of a male,
and a male has an X and a Y chromosome.
3. Identify the centromere in each pair of chromosomes. The centromere is the area where
each chromosome narrows.
4. Observe the karyotypes in Figures 4 and 5. Note the presence of any chromosomal
abnormalities.
5. Comparing and Contrasting: Of the three karyotypes that you observed, which was
normal? Which showed evidence of an extra chromosome? An absent chromosome?
6. Formulating Hypotheses: What chromosomal abnormality appears in the karyotype in
Figure 4? Can you tell from which parent this abnormality originated? Explain your
answer.
7. Inferring: Are chromosomal abnormalities such as the ones shown confined only to
certain parts of the body? Explain your answer.
8. Using the incomplete chromosomal analysis provided by the lab, determine the probable
identity of the mystery donor.
Incomplete Karyotype Analysis – provided by the Forensics Dept. Long Island, New York
Results/Conclusions:
1. Draw a data table in the space below in which to record your observations of the
karyotypes shown in Figures 1, 4, and 5. Record any evidence of chromosomal
abnormalities present in each karyotype. Record the genetic defect, if you know it,
associated with each type of chromosomal abnormality present.
2. Drawing Conclusions: Are genetic defects associated with abnormalities of autosomes or
of sex chromosomes? Explain your answer.
3. Posing Questions: Formulate a question that could be answered by observing
chromosomes of different species of animals.
Security Camera Footage from Courthouse
Subject
Disorder
Description
Hand Size (cm.) / Eye
Color
Ted: L 25 X W 17
Tonia: L 18 X W 13
Down
syndrome
Extra
chromosome
21
Ted: Brown
Tonia: Green
Brian: L 23 X W 16
Klinefelter
syndrome
Extra X in
male (XXY)
Brian: Green- Hazel
Anita: L 19 X W 12
Turner
syndrome
Single X in
female (XO)
Anita: Blue-green
Name: ______________________________________ Date: ________________________
Student Exploration: Human Karyotyping
Vocabulary:
 Autosome – a chromosome that is not a sex chromosome.
o Humans have 22 pairs of autosomes.

Chromosomal disorder – a type of genetic disorder that involves missing or extra copies
of chromosomes or a change in chromosome structure.
o Chromosomal disorders are typically caused when an error occurs during cell
division and the chromosomes do not separate properly.
o Down syndrome is one of the most common chromosomal disorders. It affects
approximately 1 out of every 800 babies.

Chromosome – a rod-shaped structure within a cell’s nucleus that is
composed of DNA and proteins.
o Chromosomes are passed from one generation to the next.
o All of the chromosomes in a human cell contain around 6 million
nucleotides and 30,000 genes.
o Chromosomes exist in duplicated or unduplicated forms. A duplicated
chromosome is shown at right. The Human Karyotyping Gizmo™
shows unduplicated chromosomes.

Karyotype – a picture of a cell’s complete set of chromosomes grouped together in pairs
and arranged in order of decreasing size.
o Karyotypes are used to detect chromosomal disorders and to study the
relationship between different species.

Sex chromosome – one of two chromosomes that determine an individual’s sex.
o In humans and most other mammals, the two sex chromosomes are the X
chromosome and the Y chromosome. Females have two X chromosomes (XX).
Males have one X chromosome and one Y chromosome (XY).
o Not all animals have the same sex chromosomes as humans. For example, the
sex chromosomes of birds and some lizards are the Z and W chromosomes.
Female birds are ZW, and male birds are ZZ.
Prior Knowledge Question (Do this BEFORE using the Gizmo.)
A chromosome is a rod-shaped structure made of coils of DNA. Most human cells have 23
pairs of chromosomes.
1. Why do you think humans have two sets of 23 chromosomes? (Hint: Where did each set
come from?) _______________________________________________________________
_________________________________________________________________________
2. How do you think different people’s chromosomes would compare? ___________________
_________________________________________________________________________
Gizmo Warm-up
Scientists use karyotypes to study the chromosomes in a cell. A
karyotype is a picture showing a cell’s chromosomes grouped
together in pairs.
In the Human Karyotyping Gizmo™, you will make karyotypes for five
individuals. Take a look at the SIMULATION pane. Use the arrows to
click through the numbered list of chromosomes at the bottom right of
the pane.
1. How does the appearance of the chromosomes change as you
move through the list? _________________________________
___________________________________________________
___________________________________________________
2. Examine the chromosomes labeled x and y. How do these two chromosomes compare?
______________________________________________________________________
______________________________________________________________________
Activity A:
Male and female
karyotypes
Get the Gizmo ready:
 Click Reset.
Question: How are male karyotypes different from female karyotypes?
1. Compare: In the SIMULATION pane, make sure Subject A is selected. Click on and drag
one of subject A’s chromosomes to the area labeled Identify. Use the arrows to compare the
chromosome you picked with chromosomes 1 through 22 and also with X and Y.
Which chromosome did you select? ____________________________________________
2. Create: Drag the chromosome to the appropriate position on the KARYOTYPING pane.
Then select another chromosome, identify it, and place it on the karyotype.
When you have identified and placed all of the chromosomes, click the camera ( ) to take
a snapshot of the karyotype. Paste the snapshot into a document, and label it “Subject A.”
3. Count: Chromosomes 1 through 22 are called autosomes. Examine the karyotype you have
created. How many total autosomes do human cells have? __________________________
4. Draw conclusions: Look at chromosome pair 23. These chromosomes are known as sex
chromosomes because they determine the sex of an individual. Females have two copies
of the X chromosome. Males have one X chromosome and one Y chromosome.
Examine the karyotype. Is subject A a male or female? _____________________________
How do you know? _________________________________________________________
Click the DIAGNOSIS tab to check your answer.
5. Analyze: Select Subject B from the SIMULATION pane. Complete subject B’s karyotype.
Take a snapshot of the completed karyotype, paste it into your document, and label it.
Examine the karyotype. Is Subject B a male or female? _____________________________
How do you know? _________________________________________________________
Click the DIAGNOSIS tab to check your answer.
6. Think and discuss: On the SIMULATION pane, compare the X and Y chromosomes. Which
chromosome do you think has more DNA? Explain. ________________________________
_________________________________________________________________________
Activity B:
Chromosomal
disorders
Get the Gizmo ready:
 Click Reset.
Question: How can you use a karyotype to diagnose a disease?
1. Compare: Select Subject C from the SIMULATION pane. Identify each of subject C’s
chromosomes, and place them on the KARYOTYPING pane. Once you have completed the
karyotype, take a snapshot of it. Paste the snapshot into a document. Label it “Subject C.”
How does subject C’s karyotype differ from a normal karyotype?
_________________________________________________________________________
2. Diagnose: A chromosomal disorder occurs when a person’s cells do not have the correct
number of chromosomes. The table below lists three common chromosomal disorders.
Disorder
Description
Down
syndrome
Extra
chromosome
21
Klinefelter
syndrome
Extra X in
male (XXY)
Turner
syndrome
Single X in
female (XO)
Subject
Symptoms
Use the table to determine which disorder subject C has. Record your diagnosis in the third
column of the table, and then click on the DIAGNOSIS tab to check your answer. Summarize
the information on the DIAGNOSIS tab in the fourth column of the table.
3. Repeat: Complete the karyotypes for Subject D and Subject E. Determine which disorder
each subject has, and use the information from the Gizmo’s DIAGNOSIS tab to complete the
table. Be sure to keep snapshots of both karyotypes.
4. Generalize: Another chromosomal disorder, called Edward’s syndrome, occurs when a
person’s cells have three copies of chromosome 18. People who have Edward’s syndrome
are severely mentally retarded and their skeletons are malformed. Most people with
Edward’s syndrome die in infancy.
Use the above information about Edward’s syndrome and the descriptions of Down
syndrome, Klinefelter syndrome, and Turner syndrome in the table on the previous page to
compare these four different chromosomal disorders.
A. Which type of chromosomal disorders seems to have the greatest affect on a person’s
health—disorders involving autosomes or sex chromosomes?
___________________________________________________________________
B. Why do you think this might be the case? __________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
5. Analyze: Examine the karyotype snapshot of the person you diagnosed with Down
syndrome.
What sex is this person? _____________________________________________________
In the United States, approximately 53% of infants born with Down syndrome are male.
6. Extend your thinking: Klinefelter syndrome only affects males, and Turner syndrome only
affects females. Examine the karyotypes of the subjects you diagnosed with Klinefelter
syndrome and Turner syndrome. How do you think sex is determined in a person with a
chromosomal disorder involving the sex chromosomes?
_________________________________________________________________________
_________________________________________________________________________
7. Apply: Trisomy X is a genetic disorder in which the individual has three X chromosomes.
Individuals with trisomy X are normal and do not show any particular symptoms.
What sex would a person with trisomy X be? Explain. ______________________________
_________________________________________________________________________
Refer to the following documents:


Topic 12 of the Biology Pacing Guide and page 62 of the Biology Item Specification
Guide.
Topic 13 of the Biology Pacing Guide and page 65 of the Biology Item Specification
Guide.