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DNA FINGERPRINTS

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Page 1: DNA FINGERPRINTS. A DNA fingerprint is a pattern of bands made from specific DNA fragments of an individual’s DNA

DNA FINGERPRINTS

Page 2: DNA FINGERPRINTS. A DNA fingerprint is a pattern of bands made from specific DNA fragments of an individual’s DNA

A DNA fingerprint is a pattern of bands made from specific DNA fragments of an individual’s DNA.

Page 3: DNA FINGERPRINTS. A DNA fingerprint is a pattern of bands made from specific DNA fragments of an individual’s DNA

DNA analysis can be used for the following:

1) The banding patterns of the DNA fragments from two different individuals may be compared to establish whether they are related. (…such as in establishing paternity).

Page 4: DNA FINGERPRINTS. A DNA fingerprint is a pattern of bands made from specific DNA fragments of an individual’s DNA
Page 5: DNA FINGERPRINTS. A DNA fingerprint is a pattern of bands made from specific DNA fragments of an individual’s DNA

2) DNA fingerprints of members of different species can be compared to determine how closely the species are related.(…such as in evolutionary biological studies)

Page 6: DNA FINGERPRINTS. A DNA fingerprint is a pattern of bands made from specific DNA fragments of an individual’s DNA

• DNA fingerprints can also be used for identification of organisms in an ecosystem, such as the salmon in a particular stream.

Page 7: DNA FINGERPRINTS. A DNA fingerprint is a pattern of bands made from specific DNA fragments of an individual’s DNA

3) Using DNA fingerprints to compare samples of blood or tissue found at a crime scene with a suspect’s blood sample may even help solve a crime (…such as in criminology & forensics)

Page 8: DNA FINGERPRINTS. A DNA fingerprint is a pattern of bands made from specific DNA fragments of an individual’s DNA

DNA samples from relatives helped confirm identity yesterday

• Yesterday morning, a test that compared the dead man’s DNA with samples collected from relatives, confirmed that the Al Qaeda leader had been killed, the official said on condition that he not be identified.

• Genetic material taken from siblings and other close relatives can be used to confirm a person’s identity because people who are related share genetic material. Siblings, for example, share on average half of their genes.

May 3, 2011

Page 9: DNA FINGERPRINTS. A DNA fingerprint is a pattern of bands made from specific DNA fragments of an individual’s DNA

• Dr. Frederick Bieber, a medical geneticist at Brigham and Women’s Hospital with expertise in using DNA for identification, said that such analysis is commonly used, for example to identify people’s remains after mass disasters, such as Hurricane Katrina.

• To do the testing, researchers extract DNA from a sample, then use a process called polymerase chain reaction to make many copies of specific sections of interest. Dyes are then added to allow comparisons of DNA fragments. Such work can be carried out rapidly — “in a hurry, overnight, in less than 24 hours,’’ Bieber said, in laboratories that exist in most developed countries.

Page 10: DNA FINGERPRINTS. A DNA fingerprint is a pattern of bands made from specific DNA fragments of an individual’s DNA

• If the relative is a brother, scientists may look at areas of the Y chromosome, which only men have.

• If the sample comes from a sibling who had the same mother, scientists might look at mitochondrial DNA, which is passed on by mothers to their children. A mathematical technique known as a kinship analysis is used to assess the likelihood the genetic material comes from people who are related.

Page 11: DNA FINGERPRINTS. A DNA fingerprint is a pattern of bands made from specific DNA fragments of an individual’s DNA

1) DNA must be extracted for analysis. (DNA may come from people or other organisms, as well as specimens such as blood or other tissue residues, possibly left at crime scenes or on victims of crimes)

Page 12: DNA FINGERPRINTS. A DNA fingerprint is a pattern of bands made from specific DNA fragments of an individual’s DNA

2) A DNA sample may be amplified. A small sample may be increased amount of DNA for testing through a procedure called polymerase chain reaction (PCR).

Page 13: DNA FINGERPRINTS. A DNA fingerprint is a pattern of bands made from specific DNA fragments of an individual’s DNA

3) Sample DNA is cut into fragments of different sizes by restriction enzymes.

DNA is prepared for fingerprinting by using a process called restriction fragment length polymorphism (RFLP) which cut the DNA at specific nucleotide sequences.

The number of fragments and the length of each fragment varies from person to person. (Specific polymorphic regions are targeted. These regions vary in people)

Page 14: DNA FINGERPRINTS. A DNA fingerprint is a pattern of bands made from specific DNA fragments of an individual’s DNA

4) The fragments of DNA are then separated using a technique called gel electrophoresis. It separates the fragments according to size and charge.

Page 15: DNA FINGERPRINTS. A DNA fingerprint is a pattern of bands made from specific DNA fragments of an individual’s DNA

• DNA fragments samples are placed in wells in the gel.

• An electric current is run through the gel. The negatively charged DNA fragments migrate towards the positive end of the gel.

Page 16: DNA FINGERPRINTS. A DNA fingerprint is a pattern of bands made from specific DNA fragments of an individual’s DNA
Page 17: DNA FINGERPRINTS. A DNA fingerprint is a pattern of bands made from specific DNA fragments of an individual’s DNA

5) DNA fragments are split. Radioactive probes bind to complimentary, single chain, fragments of the DNA in the samples, forming visible bands when exposed to photographic film.

Page 18: DNA FINGERPRINTS. A DNA fingerprint is a pattern of bands made from specific DNA fragments of an individual’s DNA

6) The exposed film is developed to reveal a DNA fingerprint. The bands can then be analyzed visually or with a computer.

Page 19: DNA FINGERPRINTS. A DNA fingerprint is a pattern of bands made from specific DNA fragments of an individual’s DNA

The DNA fingerprinting technology compares small segments of DNA that tend to vary the most from person to person.

These segments are “noncoding” regions where DNA repeats over and over again.

Page 20: DNA FINGERPRINTS. A DNA fingerprint is a pattern of bands made from specific DNA fragments of an individual’s DNA

The photograph shows 8 columns on a gel. Several of these columns contain DNA fingerprints of samples taken from a crime scene, a victim, and four suspects.

• Which suspect’s DNA fingerprint matches the blood found at the crime scene?

• How likely is it that blood found at the crime scene belongs to the suspect?

Page 21: DNA FINGERPRINTS. A DNA fingerprint is a pattern of bands made from specific DNA fragments of an individual’s DNA

Virtual DNA Lab

• http://www.scq.ubc.ca/dna-restriction-digest-and-gel-electrophoresis-a-virtual-lab/