Chapter 7: DNA Profiling
Student Learning Objectives
Forensic Science: Fundamentals and Investigations, 2nd ed., Bertino & Bertino, 2015
At the conclusion of this chapter, the student should be able to do:
DNA Background
_____1. Write the full name of the DNA molecule
_____ 2. Describe the structure of a DNA molecule as proposed by Watson and
Crick in 1953.
_____3. List four nitrogenous bases found in a DNA molecule.
_____ 4. Explain the complementary base pairing of DNA.
_____ 5. State the function of a DNA molecule.
_____ 6. Compare the DNA sequences found in
a. Two unrelated individuals.
b. Two related individuals.
c. Identical twins.
_____ 7. Describe two different organelles within a cell where DNA can be found.
_____ 8. Compare and contrast nuclear DNA with mitochondrial DNA (mtDNA) in
regards to:
a. Quantity within the cell
b. Inheritance from the parents
c. Durability
d. Role of each in identification of persons
_____ 9. Discuss the relationship between DNA and chromosomes.
_____ 10. Discuss the relationship between genes and chromosomes.
_____ 11. What is the function of a gene?
_____12. Describe what is meant by the term human genome. Include
a. Number of genes
b. Location of the genes
_____ 13. Distinguish between an allele and a gene.
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_____ 14. Compare and contrast an intron and an exon.
a. Which one codes for a protein or function?
b. Describe the forensic significance of each.
c. Which one is more numerous within the human genome?
____15. Discuss karyotypes.
a. What is a karyotype?
b. How are chromosomes arranged in a karyotype?
c. How is the sex of a subject determined by viewing his or her karyotype?
_____16. Summarize the process for extracting DNA from cells.
Nuclear DNA and Mitochondrial DNA (mtDNA)
_____ 17. Compare and contrast mitochondria DNA (mtDNA) to nuclear DNA
a. Location
b. Source
c. Function
_____ 18. Explain why mtDNA is inherited only from the mother.
_____ 19. Discuss the advantage of using mtDNA instead of nuclear DNA in an attempt
to identify the remains of an individual. What is the disadvantage?
Y Chromosome
______20. Explain how the gender of a child is determined by the father.
______21. Discuss how paternal inheritance can be traced using the Y chromosome.
DNA Evidence
______22. List four different sources of DNA that can be collected from a suspect.
______23.Summarize how to properly collect and package DNA evidence.
______ 24. Classify nuclear DNA and mtDNA as individual, familial, or class evidence.
Cite evidence to support your claim.
______ 25. Describe the importance of a polymerase chain reaction (PCR) to DNA
profiling.
______ 26. Cite arguments to support the statement that forensic DNA analysis is
possible because of PCR reactions.
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______27. Support the statement that CODIS and technology have significantly
improved the ability to solve crimes with DNA evidence.
Include in your answer:
a. What is CODIS?
b. Whose DNA is entered into CODIS?
c. How do state laws influence whose DNA is entered into CODIS?
d. How has CODIS helped to identify repeat offenders?
e. How has CODIS improved communications between investigators?
_____28. List questions that would be asked of a DNA analysis expert in court about how
DNA evidence was handled and analyzed to ensure evidence reliability.
DNA Fingerprinting or Gel Electrophoresis
(Mastery of items 31–37 requires you to have taught the gel electrophoresis lesson on the
IRCD, Ch. 7 TN DNA Fingerprinting Using Gel Electrophoresis.)
_____ 29. Briefly describe how gel electrophoresis is used to separate DNA.
_____ 30. Discuss how restriction enzymes are used in DNA fingerprinting.
_____ 31. Given a picture of a DNA fingerprint, to be able to identify
a. The largest band.
b. The smallest band.
_____ 32. State the role of each of the following items in Gel Electrophoresis:
a. Gel
e. Power Source
b. Wells
f. Restriction Enzymes
c. Positive Electrode
g. Plastic combs
d. Negative Electrode
h. Gel Box
_____ 33. Explain how to load the digested DNA into a well using a pipette.
_____34. Distinguish between loading dye and stain.
_____ 35. Explain the role of the standard DNA in gel electrophoresis.
_____ 36. Describe the composition and role of radioactive probes and their use in DNA
fingerprinting.
_____ 37.Interpret a DNA profile produced by gel electrophoresis and determine if the
crime-scene DNA is consistent with the DNA of a suspect.
_____ 38. Compare and contrast DNA fingerprinting to regular fingerprinting:
a. What do they have in common?
b. Describe how they differ?
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c.
How are they each used in forensics?
STR Analysis
______39. Elaborate on STRs used in DNA analysis.
a. STR is an abbreviation for which words?
b. Where do you find STRs?
c. How many bases are usually found within an STR?
d. List several examples of STRs.
e. If two people have different forms of the same STR (different alleles
why is there no phenotypic difference between the persons?)
_____ 40. Distinguish between the terms homozygous and heterozygous STR genotypes.
______41. Model how STRs are inherited from parents to form different STR
combinations in their offspring.
_____ 42. Given the STR profiles of the crime-scene DNA and suspect’s DNA, be able
to include or exclude a suspect.
_____43. Describe how gene frequencies for different STRs are determined using
population databases.
_____44. Describe the role of each of the following in STR Typing.
a. Fluorescent primers
b. Capillary tubes
c. Prism
d. Electronic detector
_____ 45. Refer to Figure 7-8 "Steps in STR Typing." Using the image, describe how
DNA STR alleles are separated by size and color by this automated device.
_____46. Discuss why different STR frequency tables must be used when investigating
allele frequencies in different parts of the world.
_____47. Describe how to calculate the frequency of specific genotype combinations of
STRs given the alleles for a
a. homozygous genotype
b. heterozygous genotype
_____48. Given the individual allele frequencies for different STR alleles used in a DNA
profile, explain how to calculate the odds that another person could have the
same DNA combinations.
____ 49. Describe the role of Y-STR analysis and how it is used to identify a paternal
line of inheritance.
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____ 50. Argue why Y-STR analysis is not considered to be a form of individual
identification.
____51. Discuss how Y-STR analysis of a father or brother been used to help confirm the
identity of a suspect at-large for whom a DNA sample has been obtained.
____ 52. Debate whether taking familial DNA to identify an at-large suspect is a
violation of civil liberties.
____53. Debate the issue of entering arrestee DNA into CODIS (as opposed to only
entering convicted felons). Is this a way to solve more crimes, or is it a
violation of one's civil liberties?
Applications of DNA Profiling
_____ 54. Explain how DNA profiling is used to determine if specimens come from
related or unrelated individuals.
_____ 55. Apply your knowledge of DNA profiling to determine the paternity of a child
using the DNA profiles of the child, mother, and potential father.
_____ 56. Explain the role of DNA profiling in:
a. Individual identification from evidence DNA
b. Identification of missing persons
c. Determination of paternity
d. Gender determination
_____57. Discuss the Innocence Project
a. What are the goals of The Innocence Project?
b. Describe the success of The Innocence Project to date
c. Explain the role of proper evidence collection and storage of DNA in
the success of The Innocence Project
____58. Summarize how the skeletal remains of the Romanovs were identified using
STR analysis and mtDNA.
____59. Using the STR profiles of the Tsar and Tsarina of Russia and the STR profile of
Anna Anderson, determine if Anna Anderson was or was not their daughter,
Anastasia.
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