Mitochondrial DNA Homework: Review and Activities
1. Give yourself an online Review of mtDNA. Go to:
http://www.geneticorigins.org/mito/mitoframeset.htm Select “Media/Animation.” Under the
Theory heading, select “Evolution of the Mitochondrial Genome.” Review all the slides.
2. Test your understanding by completing “Solving the Mystery of the Romanovs.” From
http://www.geneticorigins.org/mito/mitoframeset.htm, again select Media/Animation. You’ll
find the Romanov’s under Problems.
3. You can find more details about the Romanov family at http://www.dnai.org/d/index.html.
Select “Recovering the Romanovs”. Then select “The Romanov Family”. Click on slides 1 –
10 and read them. Select “The mystery of Anna Anderson” and read slides 1 - 6.
Mitochondrial DNA Homework: Review and Activities
4. Give yourself an online Review of mtDNA. Go to:
http://www.geneticorigins.org/mito/mitoframeset.htm Select “Media/Animation.” Under the
Theory heading, select “Evolution of the Mitochondrial Genome.” Review all the slides.
5. Test your understanding by completing “Solving the Mystery of the Romanovs.” From
http://www.geneticorigins.org/mito/mitoframeset.htm, again select Media/Animation. You’ll
find the Romanov’s under Problems.
6. You can find more details about the Romanov family at http://www.dnai.org/d/index.html.
Select “Recovering the Romanovs”. Then select “The Romanov Family”. Click on slides 1 –
10 and read them. Select “The mystery of Anna Anderson” and read slides 1 - 6.
Mitochondrial DNA Homework: Review and Activities
7. Give yourself an online Review of mtDNA. Go to:
http://www.geneticorigins.org/mito/mitoframeset.htm Select “Media/Animation.” Under the
Theory heading, select “Evolution of the Mitochondrial Genome.” Review all the slides.
8. Test your understanding by completing “Solving the Mystery of the Romanovs.” From
http://www.geneticorigins.org/mito/mitoframeset.htm, again select Media/Animation. You’ll
find the Romanov’s under Problems.
9. You can find more details about the Romanov family at http://www.dnai.org/d/index.html.
Select “Recovering the Romanovs”. Then select “The Romanov Family”. Click on slides 1 –
10 and read them. Select “The mystery of Anna Anderson” and read slides 1 - 6.
1
The Hunt for mtDNA
You are a forensic scientist recruited to help solve a long-standing "missing persons" case.
Mitochondrial DNA, or mtDNA for short, is the key to your success.
Procedure
1. Read the Guidelines for mtDNA Inheritance in the box at the bottom of this page.
2. A body has been found in a field in Paradise, PA. The bones are so weathered that
mtDNA is all that can be recovered. The Stoltzfus family claims the body is their long-lost
relative George. Identify which family members in the Who’s Related by mtDNA pedigree
should be chosen to donate their mtDNA for comparison with the mtDNA from the
bones? (George Stoltzfus is marked in the pedigree with a question mark.) All deceased
individuals have been cremated and cannot be sampled for mtDNA.
3. Connect individuals who share mtDNA from the great-great grandmother by darkening
the lines that link them to one another.
4. Of the individuals connected by dark lines, circle the living relatives who are eligible to be
tested for mtDNA.
Guidelines for mtDNA Inheritance
Mitochondrial DNA (mtDNA) is found in each cell's mitochondria,
structures that produce ATP, the cell's main energy source. Here are
some guidelines about how mtDNA is inherited:
 mtDNA can only be inherited from a woman.
 A man can inherit mtDNA from a woman.
 A man cannot pass mtDNA on to any children.
Who's Related by mtDNA?
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Questions
1. How many living relatives could provide mtDNA to test against the mtDNA of the
discovered remains that are believed to belong to the missing person shown by a
question mark in the pedigree chart?
2. Describe the inheritance pattern of mtDNA.
3. If two brothers died in a crash, could you use mtDNA to distinguish their remains one
from the other? Why or why not?
4. How far back could you trace a lineage of mtDNA?
Several other families have now come forward to claim the Mystery Man’s body. In addition to
the Stoltzfus family, the Martin family and the Weaver family also think he’s a long-lost relative.
Mitochondrial sequencing of the Mystery Man’s mtDNA shows a few differences from the
reference sequence. (Differences are marked with bold, capital letters. The rest of the
sequence is identical.)
Mystery Man’s Sequence
16251 caaagccacT cctcacccac taggatacca acaaacctac ccacccttaa cagtacatag
16311 tacataaagc catttaccgt acatagcaca ttacagtcaa atcccCtctc
Reference Sequence
16251 caaagccacC cctcacccac taggatacca acaaacctac ccacccttaa cagtacatag
16311 tacataaagc catttaccgt acatagcaca ttacagtcaa atcccTtctc
What is the Mystery Man’s Haplotype?
5. Where does the Mystery Man’s mitochondrial sequence differ from the reference
sequence?
6. Determine the Mystery Man’s haplotype using the same notation from class today and
from the “Local Mennonite and Amish Mitochondrial Haplotypes” handout.
Which is his family?
Mitochondrial analysis of carefully selected members of the Martin, Stoltzfus and Weaver
families give the haplotypes shown in the table below.
Haplotype
T16362C
C16260T, T16356C
C16294T, T16304C
Family
Martin
Stoltzfus
Weaver
7. Which family does the Mystery Man belong to?
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8. Use the the “Local Mennonite and Amish Mitochondrial Haplotypes” handout to
determine whether he is likely to be Groffdale Mennonite, Weaverland Mennonite,
Lancaster Amish, or Juniata/Mifflin Amish? Explain why.
Local Mennonite and Amish Mitochondrial Haplotypes
Groffdale
Weaverland Lancaster Juniata/Mifflin
Haplotype
Mennonite
Mennonite
Amish
Amish
T16298C_T16311C
17
2
0
0
C16069T_T16126C_C16261T
11
7
0
0
T16304C
6
2
0
2
T16093C_T16304C
5
4
0
0
T16362C
4
0
0
0
T16126C_C16294T_C16296T
3
3
0
0
A16051G_T16092C_G16129C_
3
0
10
0
A16183C_ T16189C_T16362C
C16294T_T16304C
2
4
1
1
T16189C
2
0
0
0
G16274A
1
0
0
0
T16093C
1
0
0
0
C16239T
0
2
0
0
T16224C
0
1
0
0
C16260T_T16356C
0
0
14
0
G16129A_C16264T_T16311C
0
0
6
1
T16124C_T16189C_T16356A
0
0
2
4
C16085T
0
0
1
0
T16093C_C16221T
0
0
1
1
T16298C
0
0
1
0
T16356C
0
0
1
0
9. If his haplotype was C16294T, T16304C, could you determine his family? Could you
determine whether he is likely to be Groffdale Mennonite, Weaverland Mennonite,
Lancaster Amish, or Juniata/Mifflin Amish?
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Explanation of pedigree and mtDNA
Everyone carries two types of DNA: nuclear DNA, found in the nucleus of each body cell, and mitochondrial DNA
(mtDNA), found in the mitochondria located in the cell's cytoplasm outside the nucleus. Nuclear DNA codes for
most proteins made by the cell and is responsible for the inheritance of physical traits, such as hair color or whether
a person has dimples, as well as inherited genetic disorders, such as sickle cell anemia or Tay-Sachs disease.
Mitochondrial DNA codes for its own proteins and for ribosomal and transfer RNAs.
During reproduction, the father's sperm cell—which contains both nuclear DNA and mtDNA—donates only its
nuclear DNA to the zygote that results from the fusion of the sperm with an egg cell. (Some researchers argue that
a fragment of the father's mtDNA is in fact passed on, though it represents much less than 1 percent of the total.)
Therefore, all the DNA in a person's mitochondria comes from his or her mother. This means that each new
generation has only the mtDNA of the mother, who has only the mtDNA of her mother, and so on. (Males have only
the mtDNA of their mothers as well but do not pass it on.) As a result, mtDNA samples can be used to identify any
maternally related individuals.
The people related to the missing person's maternal grandmother (who are the candidates for getting mtDNA to
compare to that of the missing person), are connected with heavy lines in the pedigree chart below. The 10 living
relatives eligible for testing are shaded.
Who's Related by mtDNA?
Mitochondrial DNA could be used to confirm that two brothers with the same mother who died in a crash were
related, but not to distinguish the brothers' remains from each other in the way that nuclear DNA could. In theory,
mtDNA could be traced back to the first "mitochondrial Eve," a woman whom scientists have tried to pinpoint.
However, controversy exists regarding the usefulness and accuracy of molecular clocks used to date when a
mitochondrial Eve might have lived. (Molecular clocks are based on assumptions about how regularly DNA
mutations occur.)
Answers to Questions:
1. There are 10 living relatives who could provide mtDNA to test against the missing person’s.
2. Mitochondrial DNA is transferred from mother to children.
3. Two brothers would share the same mother and therefore have identical mtDNA. mtDNA could not be used to
distinguish between two brothers.
4. Theoretically, mtDNA could be used to track back to the “mitochondrial eve”, but there is debate about the
accuracy.
5. At base 16260 he has a T instead of a C and at base 16356 a C instead of a T.
6. C16260T, T16356C
7. His haplotype matches that of the Stoltzfus family.
8. His haplotype is found only in the Lancaster Amish.
9. You could determine that his family is the Weaver family. You could not determine the group because the
same haplotype occurs in all four groups. Given the Weaver surname, Weaverland is a strong possibility.
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