DNA Technology

2. DNA TECHNOLOGY
Technology used to help with genetic
engineering  helps us:
1. identify genes for specific traits
2. transfer genes for a specific trait from one
organism to another
3. cure disease
4. treat genetic disorders
5. improve food crops

3. HOW CAN YOU GET A DESIRED TRAIT WITHOUT
DIRECTLY MANIPULATING THE ORGANISMS
DNA?
1. HYBRIDIZATION; crossing organisms of
different traits to produce a hardier product ex:
mule
2. INBREEDING/SELECTIVE BREEDING; maintain
the present genes by breeding only within the
population ex: pedigree animals
3. INDUCING MUTATIONS; radiation, chemicals 
polyploidy (3N or 4N) plants resulted  larger
and hardier

4. NOW LET US MANIPULATE THE GENES BY
ALTERING THE ORGANISMS DNA
a) DNA Technology: sci. involved in the ability to
manipulate genes/DNA
a) Cure disease
b) treat genetic disorders
c) Improve crops

5. TOOLS:
1. DNA extraction
2. Restriction enzymes
3. Gel electrophoresis
4. DNA ligase
5. Polymerase chain rxn. (PCR)

6. METHOD: (5 STEPS)
1.Extract gene  insulin
2.Cut insulin producing gene out using “restriction enzymes”
1.Sticky ends  create overhang
2.Blunts no overhangs
3.Cutting clone vector cut plasmid with same restriction
enzyme
4.Ligation: donor gene is spliced into plasmid DNA, DNA
ligase glues it
(this forms recombinant DNA = plasmid DNA + new piece of
DNA)
5.Plasmid returned to bacterium & reproduces using donor
gene in it (this is transgenic organism = organism with foreign
DNA incorporated in it’s genome)
6.*reproduce*

7. RESTRICTION ENZYMES
BACTERIAL ENZYMES are used to
cut DNA molecule into more
manageable pieces
They recognize certain sequences
Creating “single-chain” tails in DNA
 called STICKY ENDS

8. STICKY ENDS
Readily bind to complimentary chains
of DNA therefore pieces of DNA that
have been cut with the same
restriction enzyme can bind
together to form a new sequence of
nucleotides
Recognizes  CTTAAG

9. *

10. *

11. CLONING VECTORS
Cloning vector is a carrier that is used to clone a
gene and transfer it from one organism to
another.
Many bacteria contain a cloning vector called a
PLASMID.
PLASMID  is a ring of DNA found in a bacterium
in addition to its main chromosome.

12. PROCEDURE
To be used as a cloning vector in gene
transfer experiments a plasmid is
isolated from a bacterium.
Using restriction enzymes the plasmid is
then cut and a DONOR GENE (specific
gene isolated from another organism is
spliced into it)
Then the plasmid is returned to the
bacterium, where it is replicated as the
bacterium divides, making copies of the
donor gene.
Plasmid now contains a GENE CLONE

13. *

14. CLONING VECTORS
!

15. PLASMID
*

16. TRANSPLANTING GENES
In some cases, plasmids are used to transfer a
gene to bacteria so that the bacteria will
produce a specific protein
Ex: INSULIN = protein that controls sugar
metabolism
Bacteria that receives the gene for insulin will
produce insulin as long as the gene is not turned off

17. STEPS:
1. ISOLATING A GENE – isolate the DNA from
human cells and plasmids from the bacteria
Use restriction enzyme
Splice human DNA into plasmids to create a
genomic library (set of thousands of DNA pieces
from a genome that have been inserted into a
cloning vector)

18. Steps cont…
2. PRODUCING RECOMBINANT DNA =
combination of DNA from 2 or more sources
Inserting a donor gene such as human gene for
insulin, into a cloning vector, such as bacterial
plasmid results in a recombinant DNA molecule!

19. Steps cont…
3. CLONING DNA – the plasmid containing recomb.
DNA is inserted into a host bacterium (called
transgenic organism
The trans. Bact. Is placed in a nutrient medium
where it can grow and reproduce.

20. *

21. *

22. EXPRESSION OF CLONED GENES
Sometimes PROMOTERS
must also be transferred so
the genes will be turned on.
Genes are often turned off
until the proteins they code
for are needed.

23. PRACTICAL USES OF DNA TECHNOLOGY
1. Pharmaceutical products: insulin, HBCF (human blood clotting factor)
2. Genetically engineered vaccines
3. Increased agriculteral yields
4. Improving quality of produce
1.Slow down ripening
2.Enhance color
3.Reduce fuzz
4.Increase flavor
5.Frost resistance

24. NEGATIVES
Allergies
Label’s don’t include all information
May create “super weeds”

25. GENE THERAPY
Treatment of genetic disorders
Ex: cystic fibrosis

26. DNA TECHNOLOGY TECHNIQUES
I. DNA Fingerprints  pattern of bands made up of
specific fragments from an individual’s DNA
USED FOR:
DETECTION OF A RELATIVE
SIMILARITIES BETWEEN SPECIES

27. HOW DO YOU MAKE DNA
FINGERPRINTS?
RFLP (restriction fragment length polymorphism)
analysis
1. extract DNA from specimen using restriction
enzymes
2. separate fragments of DNA using
electrophoresis (separates DNA according to size
and charge)
3. placed in wells made on gel
4. electric current run through gel

28. Continue…
5. negative fragments migrate to
positive charged end of gel but not all
at same rate
6. pores in gel allow smaller
fragments to migrate faster 
separating fragments by size.
7. blotted onto filter paper.

29. CAN YOU TELL IF THIS COULD BE
THE FATHER?

30. ACCURACY OF DNA FINGERPRINTS
DNA fingerprints are very accurate
However, genetic tests can only
absolutely disprove, not prove,
relationship!
Courts accept 99.5% accuracy as
proof of alleged paternity

31. POLYMERASE CHAIN REACTION (PCR)
Used when you only have a TINY
piece of DNA
PCR can be used to quickly make
many copies of selected segments
of the available DNA
Use a PRIMER to initiate replication
DNA doubles every 5 minutes

32. PCR IS USED FOR:
1. crimes
2. diagnosing genetic
disorders from embryonic
cells
3. studying ancient
fragments of DNA (tiny
amounts)

33. HUMAN GENOME PROJECT
2 GOALS:
1. determine nucleotide sequence
of entire human genome (aprox 3
billion nucleotide pairs or about
100,000 genes
2. map the location of every gene
on each chromosome

34. 1996
1 % of 3 billion nucleotide pairs
of DNA human genomes were
analyzed
This allows for us to identify and
determine the function of
16,000 genes!

35. GENE THERAPY
Treating a genetic disorder by
introducing a gene into a cell or by
correcting a gene defect in a cell’s
genome.
Ex: Cyctic fibrosis cause one
defective gene  malfunction of
one protein

36. GENE THERAPY FOR CYCTIC
FIBROSIS
Nasal spray carrying normal
cyctic fibrosis gene to cells in
nose and lungs
Must repeat treatment
periodically

37. ETHICAL ISSUES
Many people worry about how personal genetic information will be used:
Insurance???
Employment????
Human Genome Project will
undoubtedly involve ethical decisions
about how society should use the
information! WHAT DO YOU THINK??

38. PRACTICAL USES OF DNA
TECHNOLOGY
1. produce perscription drugs
Vaccine (harmless version of a virus or a bacterium)
Pathogen (disease causing agent) treated
chemically or physically so that they can no longer
cause disease.
Pathogen (Ag)  Antibody (Ab)
DNA tech. may produce vaccines safer than
traditional ones!

39. INCREASING AGRICULTURAL YIELDS
DNA Tech.  used to
develop new strains of
plants
Ex: scientists can make
tomato plants toxic to
hornworms and effectively
protect the plant from these
pests.

40. SEE THE HORNWORM
BEGINNING TO FORM AT THE
LEAVES!

41. THIS HORNWORM EATS AND
DESTROYS THE TOMATO PLANT!

42. HORNWORMS ATTACK TOMATO PLANTS

43. CROPS THAT DO NOT NEED
FERTILIZER
Plants require NITROGEN to
make proteins and nucleic
acids
Most plants get their N from the
soil
TRANSGENIC FOOD CROPS 
contain genes for nitrogen
fixation so they can grow in
nitrogen POOR soil.

44. GENETICALLY ENGINEERED FOODS
Foods may have toxic proteins or
substances  causing
ALLERGIES
Ex: changing the gene that codes
for an enzyme to ripening in
tomatoes they are able to make
tomatoes ripen without becoming
SOFT!!

45. GENETICALLY ENGINEERED CROPS
Some are concerned that
genetically engineered crops
could spread into the wild and
wipe out native plant species.
SUPERWEEDS!!!!!!!!