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Interactive Powerpoint Forensic Genetics

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									Topics in Forensic
      By Kristen E. Rombola

  What is Forensic Genetics?

   The use of inheritable information within your cells that
    helps solve crimes, identify remains, or answer other
    questions of interest to a legal system

…Back                                                 Continue…
  Forensic Genetics Menu

   Blood Typing

   DNA Typing

   Real-Life Applications

   Blood Typing…Terms
    Antigen  a molecule recognized by the Immune System

    Heredity  genetic information that is passed from parents to
         Genotype : the specific allele makeup of a cell
         Phenotype: observable trait ( i.e. brown hair)

    ABO System
      Identifies antigens that humans have in their blood – important in
       blood transfusions
      For more info…Click Here

…Back                                                               …Next Slide
   ABO System
    Blood Type A (this is the phenotype):
      Could be AO (this is a possible genotype)
           Note: the O inherited from the one of the parents acts like its
             invisible – the child has Type A (even though the O is present)
         Could be AA (this is a possible genotype)

    Blood Type B (this is the phenotype):
      Could be BO (this is a possible genotype)
           Note: again, the O acts like its invisible
         Could be BB (this is a possible genotype)

   Click picture to enlarge
…Back                                                                   …Next Slide
   ABO System

    Blood Type AB (this is the phenotype):
      Can only be AB (this is the ONLY genotype)

    Blood Type O (this is the phenotype):
      Can only be OO (this is the ONLY genotype)


    If a father has type AB and the mother has type BO, what are the
        possible blood types of their children?
         Answer: possible genotypes AB, BB, AO, or BO
              Final Answer: Possible Blood Types are AB, B, and A

    Forget Punnett Squares? Click Here for a refresher!
…Back                                                                …Next Slide
   Uses in Forensics

    Quickly Include or Exclude Suspects by comparing
        evidence left at a a crime scene and suspect/victim’s blood
         If evidence is blood type O, and suspect is AB – it is not
          suspect’s blood!

    Settle Paternity Disputes

…Back                                                       …Test Your Knowledge
   Question 1

    If a child of blood type O has a mother
        of blood type A, can Frank (blood type
        B) be the father?

                HECK           NO
               YEAH!!!        WAY!!!

You’re right…He COULD BE the father

Frank (blood type B) could have a genotype of BO. If the mother
(blood type A) has a genotype of AO, their children could have
genotypes of AB, BO, AO, or OO
     genotype OO = Blood Type O
                           A                   O

        B                  AB                 BO

        O                  AO                 OO

                                                    …Back to MENU
Review and Try Again!!!

 Review
    DNA Typing

     DNA  deoxyribonucleic acid – our genetic material!
       A code for everything in our body
       For a refresher on DNA: CLICK HERE

     DNA Typing  technique used in forensics (and other
       fields) to identify specific sequences of DNA – like a
       person’s FINGERPRINT (unique to that individual)
     Polymorphic Genes  genes that have many phenotypes
       (i.e. the many colors of jaguars)
        The important thing about highly polymorphic genes is
           that two unrelated strangers are not likely to have the
…Back to   same piece of DNA – making people UNIQUE!!
Menu                                                          …Next Slide
   Polymerase Chain Reaction

    Uses enzymes and heat
        to AMPLIFY small
        amounts of DNA into
        large amounts of DNA

    Importance: Trace
        amount of DNA from a
        crime scene can be
        amplified and and to
        identify the culprit

    Click video to begin

…Back                          …Next Slide
   STR Analysis

    A type of DNA fingerprinting

    STR (short tandem repeats): pieces of DNA where short
        sequences repeat at different places in the genome


   CAGCAGCAGCAGCAGCAG ** 6 Repeats of CAG **

    These repeats are HIGHLY POLYMORPHIC – meaning that,
        unless you are an identical twin, your STRs are UNIQUE TO
        YOU (though you will have some similarities to your
        parents and siblings)!!!
…Back                                                        …Next Slide
   STR Analysis

    The most powerful thing about STR Analysis is its

    When looking at 3 STR Loci (a location in the genome), the
        chances that two strangers will have the same STR profile

                          1 in a Quintillion (1 x 1018)

                          ~Click for more information~

…Back                                                       …Next Slide
   DNA Profiling Example

…Back                      …Next Slide
                                         Back to Question 2
                                         Back to Question 3

    Gel Electrophoresis
   Gel Electrophoresis is a technique
     that uses electricity to move DNA
     down a gel

   Restriction enzymes cut the DNA
     and then the DNA separates by
     size on the gel.

   The resulting gel is a DNA
     fingerprint – different for
     different people

   DNA fingerprints from gel
    electrophoresis can be used to
    determine paternity as well. You
    will share HALF of your genetic
    material with each of your
…Back                                            …Next Slide
   Question 2
   DNA evidence was recovered from a sexual
   assault (middle). Which of the two suspects
   is guilty, Chris Reesh (left) or Randall Jones

   Note: this is a DNA fingerprint derived from
   gel electrophoresis

        Chris                  Randal
        Reesh                  Jones

                    Great Job!
 You’re right, Randal Jones is the culprit. His DNA
  fingerprint matched exactly. You’re ready for CSI !

                                                        …Back to Menu
Not Quite…Review and Try Again

 Review
   Violent Crimes

    Use DNA
      fingerprinting to
      match crime scene
      evidence to a
    The Statistical
       Discrimination of
       fingerprinting is
       its greatest
…Back to Menu              …Next Slide
 Forensic Genetics was heavily used in the
   identification of many 9/11 victims

 Victims DNA (gathered from previously
   stored medical specimens) were analyzed and
   catalogued in a database

 Another database was collected with the
   DNA fingerprints from victims at Ground
   Zero. These two databases were compared
   for identification of victims’ bodies.

 1585 of the 2792 people known to have died
   were identified before the search was called
   off in 2005.

 In 2007 the search was started again as
   continuing advances in technology provided
   increasingly innovative DNA fingerprinting
   techniques from even smaller DNA samples.

…Back                                             …Next Slide
   The Holocaust

   The DNA Shoah Project

    Actively building a database of
        genetic material from Holocaust
        survivors and their immediate

    The Purpose: “The Project aims to
        match displaced relatives, provide
        Shoah orphans and lost children
        with information about their
        biological families and, eventually,    Above: Modern day
        assist in the forensic identification   Auschwitz
        of Holocaust-era remains.”

    For more information Click Here
…Back                                                     …Test Your Knowledge
Question 3
 From the choices below, which is not a practical
 application of DNA Fingerprinting?
                    Diagnose Inheritable Diseases

                          Paternity Testing

      Map Human Movement Out of Africa From Prehistoric Times
                       to the Present

       Determine Why Certain People Are More Susceptible to the
                           Common Cold
Not Quite…

 DNA Fingerprinting can
  lead to the diagnosis of
  inheritable diseases by
  comparing known
  disease-causing genes
  between parents and
  their offspring.

 Review!
Oops…Not Quite Right:

 Blood Typing isn’t the only
  way to help determine

 DNA fingerprinting can
  help determine paternity
  since each parent
  contributes 50% of your
  genetic material.

 Review!
      Try Again…
 Though not discussed directly in
     this presentation, DNA
     fingerprinting can map humans’
     migration out of Africa in
     prehistoric times. This field is
     broadly known as Population
 This is done by analyzing DNA
     fingerprints and changes in
     Fingerprints through time to see
     how humans moved across the

 Learn More Here


 Review
   Excellent Thinking!
 DNA fingerprinting will not prove
  why certain people are more
  susceptible to the common cold
 Also, the “common cold” is a
  general term for many different
  viruses – each one unique from the
  next – making it difficult to find an
  underlying genetic vulnerability in
 Most importantly…Someone’s
  susceptibility to the cold is dynamic
  – always changing

                                          …Back to Menu

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