DNA profiling

• What is DNA profiling primarily used for?

  Forensic analysis
• What does STR stand for in DNA analysis?

  Short Tandem Repeat
• Why are restriction enzymes used in DNA analysis?


  They break DNA into smaller fragments for easier study
• What is the role of restriction enzymes in DNA analysis?


  They cut DNA at specific sequences
• How does the restriction enzyme EcoR1 function?


  It recognizes the sequence GAATTC and cuts between G and A
• What is the significance of restriction fragments in DNA analysis?

  They are easier to analyze than whole DNA molecules
• What is gel electrophoresis used for?


  To separate DNA fragments by size
• What are restriction fragments?


  Fragments of DNA cut by restriction enzymes
• What is an STR?

  A pattern of two or more nucleotides repeated adjacent to each other
• Where do STRs typically occur in the genome?

  In non-coding intron regions
• How can STRs create a unique genetic profile?

  By counting the number of repeats at a specific locus
• What percentage of DNA does not carry nucleotide triplets that code for proteins?

  90% or more
• Why is the number of STR repeats variable among individuals?

  It varies from one individual to the next
• How many published STR sequences are there in the human genome?

  Over 10,000
• What is the primary application of STR analysis?

  Determining genetic profiles in forensic cases
• What is the first step in DNA identification?

  Isolate DNA and make copies using PCR
• What does PCR stand for?

  Polymerase Chain Reaction
• What is the purpose of PCR?


  To produce many copies of a specific target segment of DNA
• What happens during the three-step cycle of PCR?

  Heating, cooling, and replication occur to amplify DNA
• How are DNA fragments separated in gel electrophoresis?


  By applying a voltage across a gel
• Why do shorter DNA fragments travel faster in gel electrophoresis?

  Because they can move through the gel more easily
• What is a genetic fingerprint?

  The pattern of bands produced in gel electrophoresis
• How can a genetic fingerprint be used in forensic analysis?

  If it matches a suspect's fingerprint, it can be used as evidence
• What types of samples can be used to obtain DNA from a suspect?

  Blood, cheek epithelial cells, or hair root cells
• What is the probability of all four bands matching in any person other than the suspect?

  $\frac{1}{60000}$
• What are the odds that two individuals will have the same 13-loci DNA profile?

  More than one in a billion
• What are the steps in DNA identification?

  1. Isolate DNA and make copies (PCR)
  2. Cut the DNA into shorter fragments that contain STRs (using restriction enzymes)
  3. Sort the DNA by size (gel electrophoresis)
  4. Compare samples to identify a person

  
• What are the applications of STR analysis?

  • Forensics
  • Crime investigation
  • Mass disasters
  • Paternity testing
  • Military DNA "dog tag"
  • Convicted criminal DNA databases
  • Bone marrow transplant follow-up

  
• What are the steps of PCR?

  1. Heating
  2. Cooling
  3. Replication
• What is gel electrophoresis?


  • A method to separate DNA fragments by size
  • Uses a jelly-like substance (gel)
  • DNA moves towards the positive end due to its negative charge
• What is the significance of genetic fingerprinting?

  • Matches DNA samples to suspects
  • Can be used as evidence in criminal cases
  • Helps establish parentage and relationships

  
• What is the process of obtaining DNA from a suspect?

  • Collect samples such as blood, cheek cells, or hair root cells
  • Analyze the samples for genetic fingerprinting