3: DNA Profiling
Students use blood typing agglutination tests, HLA genotyping, gel electrophoresis band patterns, and DNA fingerprinting techniques to solve paternity disputes and forensic identification problems.
LibreTexts reference: Chapter 3: DNA Profiling and Techniques 
True/False Statements About English Palindromes
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Blood Types from Agglutination Test Results
Click to show Blood Types from Agglutination Test Results example problem
During a blood typing test, anti-A, anti-B, and anti-D antibodies are added to a blood sample along with a control. A visible reaction indicates the presence or absence of the corresponding antigens.
What would the test results look like for someone with AB+ blood type?
Offspring HLA Genotypes (2 Markers, Black)
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HLA genotyping serves as a key component in the field of immunogenetics. It is used for understanding individual variations in immune responses. This molecular technique identifies unique alleles on paired chromosomes. It's particularly vital in organ transplantation for matching donors and recipients. Finding a correct match reduces the chance for graft rejection.
A mother has a HLA genotype of A2,B2 on one chromosome and A4,B5 on the other chromosome.
The father has a HLA genotype of A5,B6 on one chromosome and A6,B1 on the other chromosome.
Which one of the following combinations is a possible genotype for their offspring?
Offspring HLA Genotypes (2 Markers, Color)
Click to show Offspring HLA Genotypes (2 Markers, Color) example problem
HLA genotyping serves as a key component in the field of immunogenetics. It is used for understanding individual variations in immune responses. This molecular technique identifies unique alleles on paired chromosomes. It's particularly vital in organ transplantation for matching donors and recipients. Finding a correct match reduces the chance for graft rejection.
A mother has a HLA genotype of A3,B4 on one chromosome and A8,B9 on the other chromosome.
The father has a HLA genotype of A1,B6 on one chromosome and A6,B1 on the other chromosome.
Which one of the following combinations is a possible genotype for their offspring?
Offspring HLA Genotypes (3 Markers, Color)
Click to show Offspring HLA Genotypes (3 Markers, Color) example problem
HLA genotyping serves as a key component in the field of immunogenetics. It is used for understanding individual variations in immune responses. This molecular technique identifies unique alleles on paired chromosomes. It's particularly vital in organ transplantation for matching donors and recipients. Finding a correct match reduces the chance for graft rejection.
A mother has a HLA genotype of A4,B5,C6 on one chromosome and A2,B4,C2 on the other chromosome.
The father has a HLA genotype of A6,B7,C9 on one chromosome and A1,B1,C4 on the other chromosome.
Which one of the following combinations is a possible genotype for their offspring?
Restriction Enzyme DNA Strand Products (10 Length, 3 Sites)
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DNA Strand Question:
Examine the DNA strand shown below. The table highlights a specific portion of a much longer DNA molecule to focus on the region containing restriction sites.
| DpnI | BalI | DpnI | BalI | DpnI | |||||||||||||||||||
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | |||||||||||||
Two (2) distinct types of restriction enzyme recognition sites, DpnI and BalI, are labeled at the top of this DNA segment.
Note: The dashes at both ends of the strand indicate that the next restriction site is far away and outside the visible region. Because this segment is part of a much larger molecule, any uncut or very large fragments will not travel into the gel and will appear to be stuck in the well.
Determine the sizes of the DNA bands that would appear on an agarose gel after digestion with DpnI only.
Restriction Enzyme DNA Fragment Products (13 Length, 3 Sites)
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DNA Fragment Question: Shown below is a short DNA fragment that is only 13 kb in length. This fragment has been isolated for restriction enzyme analysis.
| PvuI | MroI | PvuI | MroI | PvuI | |||||||||||||||||||||||||
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | ||||||||||||||||
Two (2) distinct types of restriction enzyme recognition sites, PvuI and MroI, are labeled at the top of this DNA segment.
Determine the sizes of the DNA bands that would appear on an agarose gel after digestion with PvuI only.
Restriction Enzyme DNA Strand Products (16 Length, 4 Sites)
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DNA Strand Question:
Examine the DNA strand shown below. The table highlights a specific portion of a much longer DNA molecule to focus on the region containing restriction sites.
| KroI | SfuI | KroI | SfuI | KroI | SfuI | KroI | |||||||||||||||||||||||||||||
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | |||||||||||||||||||
Two (2) distinct types of restriction enzyme recognition sites, KroI and SfuI, are labeled at the top of this DNA segment.
Note: The dashes at both ends of the strand indicate that the next restriction site is far away and outside the visible region. Because this segment is part of a much larger molecule, any uncut or very large fragments will not travel into the gel and will appear to be stuck in the well.
Determine the sizes of the DNA bands that would appear on an agarose gel after digestion with KroI only.
Restriction Enzyme DNA Fragment Products (8 Length, 2 Sites)
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DNA Fragment Question: Shown below is a short DNA fragment that is only 8 kb in length. This fragment has been isolated for restriction enzyme analysis.
| SspI | MscI | SspI | |||||||||||||||||
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | |||||||||||
Two (2) distinct types of restriction enzyme recognition sites, SspI and MscI, are labeled at the top of this DNA segment.
Determine the sizes of the DNA bands that would appear on an agarose gel after digestion with SspI only.
Restriction Enzyme Overhang Sequences
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Restriction enzymes are proteins that cut DNA at specific sequences to produce fragments for further study. These enzymes are obtained from various types of bacteria and have the ability to recognize short nucleotide sequences within a larger DNA molecule.
The restriction enzyme we are focusing on is Ppu10I, which is derived from the bacterium Pseudomonas putida RFL10.Ppu10I cuts the DNA sequence as follows: 5'-A|TGCAT-3', where the '|' indicates the cleavage site.
Based on this information, which one of the following sequences below corresponds to the overhang region of the DNA after cleavage by the restriction enzyme Ppu10I?
Restriction Enzyme Cut Types (5', 3', or Blunt)
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Restriction enzymes are proteins that cut DNA at specific sequences to produce fragments for further study. These enzymes are obtained from various types of bacteria and have the ability to recognize short nucleotide sequences within a larger DNA molecule.
The restriction enzyme we are focusing on is HaeIII and is obtained from the bacteria Haemophilus aegyptius.HaeIII cuts the DNA sequence as follows: 5'-GG|CC-3' where the '|' indicates the cut location.
Based on this info, can you identify the type of cut this enzyme makes?
Restriction Enzyme Overhang Type from Cleavage Patterns
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Restriction enzymes are proteins that cut DNA at specific sequences to produce fragments for further study. These enzymes are obtained from various types of bacteria and have the ability to recognize short nucleotide sequences within a larger DNA molecule.
The restriction enzyme we are focusing on is SphI and is obtained from the bacteria Streptomyces phaeochromogenes.SphI cuts the DNA sequence as follows: 5'-GCATG|C-3' where the '|' indicates the cut location.
Based on this info, can you identify the type of cut this enzyme makes?
RFLP Paternity Testing (EASY, 3 Males)
Click to show RFLP Paternity Testing (EASY, 3 Males) example problem
The Question
Who is the father of the child?
| Mother | ||||||||||||||||||||||||||||||
| Child | ||||||||||||||||||||||||||||||
| Male 1 | ||||||||||||||||||||||||||||||
| Male 2 | ||||||||||||||||||||||||||||||
| Male 3 | ||||||||||||||||||||||||||||||
Background
Restriction Fragment Length Polymorphism (RFLP) is a molecular biology technique used to distinguish between closely related DNA samples. It's commonly employed in paternity tests, among other applications.
Disclaimer
In actual diagnostic processes, the results of RFLP for confirming paternity are often cited to provide a 99.9% accuracy level or higher. However, no test is foolproof. Legal confirmation may involve additional procedures and evaluations to ensure the integrity and admissibility of the test.
Instructions
Use the provided DNA gel profile to determine paternity. Each band in the gel corresponds to a DNA fragment. Fragments are inherited; thus, the child's DNA will have overlapping fragments with the true father.
RFLP Paternity Testing (HARD, 9 Males)
Click to show RFLP Paternity Testing (HARD, 9 Males) example problem
The Question
Who is the father of the child?
| Mother | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Child | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Male 1 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Male 2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Male 3 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Male 4 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Male 5 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Male 6 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Male 7 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Male 8 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Male 9 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Background
Restriction Fragment Length Polymorphism (RFLP) is a molecular biology technique used to distinguish between closely related DNA samples. It's commonly employed in paternity tests, among other applications.
Disclaimer
In actual diagnostic processes, the results of RFLP for confirming paternity are often cited to provide a 99.9% accuracy level or higher. However, no test is foolproof. Legal confirmation may involve additional procedures and evaluations to ensure the integrity and admissibility of the test.
Instructions
Use the provided DNA gel profile to determine paternity. Each band in the gel corresponds to a DNA fragment. Fragments are inherited; thus, the child's DNA will have overlapping fragments with the true father.
RFLP Paternity Testing (MEDIUM, 5 Males)
Click to show RFLP Paternity Testing (MEDIUM, 5 Males) example problem
The Question
Who is the father of the child?
| Mother | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Child | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Male 1 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Male 2 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Male 3 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Male 4 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Male 5 | ||||||||||||||||||||||||||||||||||||||||||||||||||
Background
Restriction Fragment Length Polymorphism (RFLP) is a molecular biology technique used to distinguish between closely related DNA samples. It's commonly employed in paternity tests, among other applications.
Disclaimer
In actual diagnostic processes, the results of RFLP for confirming paternity are often cited to provide a 99.9% accuracy level or higher. However, no test is foolproof. Legal confirmation may involve additional procedures and evaluations to ensure the integrity and admissibility of the test.
Instructions
Use the provided DNA gel profile to determine paternity. Each band in the gel corresponds to a DNA fragment. Fragments are inherited; thus, the child's DNA will have overlapping fragments with the true father.
RFLP Forensic DNA Analysis (EASY, 4 Suspects)
Click to show RFLP Forensic DNA Analysis (EASY, 4 Suspects) example problem
The Question
Which suspect left blood at the crime scene?
| Victim | ||||||||||||||||||||||||||||
| Blood | ||||||||||||||||||||||||||||
| Suspect #1 | ||||||||||||||||||||||||||||
| Suspect #2 | ||||||||||||||||||||||||||||
| Suspect #3 | ||||||||||||||||||||||||||||
| Suspect #4 | ||||||||||||||||||||||||||||
Background
Restriction Fragment Length Polymorphism (RFLP) is a molecular biology method used to differentiate between closely related DNA samples. It is often used in forensic investigations.
Disclaimer
In adherence to the principles of due process, all individuals in this exercise shall be presumed innocent until proven guilty beyond a reasonable doubt in a court of law.
Instructions
Examine the provided DNA gel profile to identify which suspect is responsible for leaving the blood sample. Each band in the gel signifies a DNA fragment. The killer's DNA will match with the blood sample found at the crime scene.
RFLP Forensic DNA Analysis (HARD, 9 Suspects)
Click to show RFLP Forensic DNA Analysis (HARD, 9 Suspects) example problem
The Question
Which suspect left blood at the crime scene?
| Victim | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Blood | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Suspect #1 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Suspect #2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Suspect #3 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Suspect #4 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Suspect #5 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Suspect #6 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Suspect #7 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Suspect #8 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Suspect #9 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Background
Restriction Fragment Length Polymorphism (RFLP) is a molecular biology method used to differentiate between closely related DNA samples. It is often used in forensic investigations.
Disclaimer
In adherence to the principles of due process, all individuals in this exercise shall be presumed innocent until proven guilty beyond a reasonable doubt in a court of law.
Instructions
Examine the provided DNA gel profile to identify which suspect is responsible for leaving the blood sample. Each band in the gel signifies a DNA fragment. The killer's DNA will match with the blood sample found at the crime scene.
RFLP Forensic DNA Analysis (MEDIUM, 5 Suspects)
Click to show RFLP Forensic DNA Analysis (MEDIUM, 5 Suspects) example problem
The Question
Which suspect left blood at the crime scene?
| Victim | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Blood | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Suspect #1 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Suspect #2 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Suspect #3 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Suspect #4 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Suspect #5 | ||||||||||||||||||||||||||||||||||||||||||||||||||
Background
Restriction Fragment Length Polymorphism (RFLP) is a molecular biology method used to differentiate between closely related DNA samples. It is often used in forensic investigations.
Disclaimer
In adherence to the principles of due process, all individuals in this exercise shall be presumed innocent until proven guilty beyond a reasonable doubt in a court of law.
Instructions
Examine the provided DNA gel profile to identify which suspect is responsible for leaving the blood sample. Each band in the gel signifies a DNA fragment. The killer's DNA will match with the blood sample found at the crime scene.