Download LEQ: How do we splice new genes into DNA?

LEQ: HOW DOES
DNA PROFILING
WORK?
12.8 to 12.12
NUCLEIC ACID PROBES
 Short single strands of DNA w/ specific nucleotide
sequences are created using radioactive isotope or dye
 These probes are used to find a specific gene or nucleotide
sequence – the probe hydrogen bonds to gene of interest
DNA MICROARRAY
DNA MICROARRAY TEST FOR GENE ACTIVITY
 mRNA that produces protein of interest is isolated, reverse
transcriptase & fluorescent nucleotides are added
 cDNA is made from RNA
 cDNA is applied to well that contain DNA from a cell;
cDNA will bind to DNA that is complementary in the wells
 Rinse unbound cDNA – fluorescent spots show DNA that
is being expressed by the cell; no glow = unexpressed DNA
 Enables a researcher to determine what genes are turned
on or off in a cell
Gel Electrophoresis
Negatively charged DNA is placed into the wells at the negative
end of the gel; apply current; negative DNA is pulled to the
positive end; smaller pieces travel farther faster; DNA fragments
are separated based on the size of the fragment (# of base pairs).
RESTRICTION FRAGMENT LENGTH
POLYMORPHISMS (RFLP’S)
 (rif′-lips) The differences in homologous DNA
sequences that are reflected in different
lengths of restriction fragments produced
when the DNA is cut up with restriction
enzymes
 Here you are looking at homologous
chromosome segments – one from a crime
scene and the other from the suspect; when
you cut both with the same restriction
enzyme, they produce different banding
patterns – This tells you the crime scene
DNA did not come from the suspect
RFLIP’s used to ID Harmful
alleles
Compare individual that has a
disease/harmful allele to others. Digest
DNA from all individuals using same
restriction enzyme. Run gel electrophoresis.
Blot DNA (pick up DNA using special filter
paper). Apply radioactive probe designed to
detect (bind to) harmful allele / gene of
interest. Unattached probes are rinsed off.
Photographic film used to form a image that
compares individuals. In this picture I had
the harmful allele. If any individual matches
the banding pattern of I, then they also have
the harmful allele. Individual II – has the
harmful allele but III doesn’t.
DNA Fingerprinting
A procedure that analyzes an
individual’s unique collection of DNA
restriction fragments, detected by
electrophoresis and nucleic acid
probes. DNA fingerprinting can be
used to determine whether two
samples of genetic material are from
the same individual.
Used to convict criminals, determine
paternity, exonerate innocent
individuals, etc…