2. Role of bacteria in technology
• Advantage to using bacteria
– Possess plasmids
• Small extra loops of DNA
– Experience transformation
• Bacteria take up plasmids from surroundings
3. Role of bacteria in technology
• Advantage to using
bacteria:
– Scientists can
genetically engineer
plasmids by inserting
gene of interest into
bacterial plasmid.
4. Gene Cloning
• Definition: using bacteria to make multiple
identical copies of a single stretch of DNA.
• Useful in understanding eukaryotic genome.
• Cloning Vector:
– Any vehicle that inserts a fragment of foreign
DNA into the genome of a host cell.
– Example: virus or genetically engineered
plasmid.
– Used in gene therapy.
5. Genetic Engineering
• Definition: Ability to
precisely manipulate DNA
sequences from widely
different organisms.
• Process requires
– Ability to cut DNA
– To insert foreign DNA
segment
– “Glue” DNA sequences
together
8. Molecular Paste
• DNA Ligase:
– Form bonds between the sugar and phosphate
backbone of the DNA molecule.
• Restriction enzymes and DNA ligase make
possible the combination of DNA from
different organisms into one DNA molecule
– Called recombinant DNA
10. How do we know what size DNA
fragments we have?
• Agarose gel
electrophoresis:
– Allows separation of
DNA on the basis of
size.
– Can visualize DNA to
determine exactly how
large it is.
11.
12. Making a DNA library
• Need the following:
– A gene of interest
– Restriction enzymes
– Plasmids
– DNA ligase
• Can create a cloning vector using these
tools which can be inserted in a bacteria
• Allow bacteria to reproduce
• DNA library: entire collection of bacterial
cells which contain cloned gene
13.
14.
15. Screening a DNA Library
• Need to find the gene of interest in the
bacteria or bacterial cells that possess the
gene of interest.
• Use nucleic acid hybridization to find the
gene of interest.
16.
17. Nucleic Acid Hybridization
• Requires a molecular probe:
– Probe is made of a synthetic single-stranded
DNA whose sequence is complementary to the
gene of interest.
– Also has a built-in marker so scientists can find
it.
• When probe binds to denatured gene of
interest, a hybrid is formed.
18.
19. Polymerase Chain Reaction
• Allows scientists to make copies of a small
sample of DNA.
• Requires:
– Primers: two synthetic short strands of DNA
that are complementary to each of the two DNA
sequences that flank the gene or DNA to be
copied.
– Heat-resistant DNA polymerase
– Nucleotides
20.
21.
22. DNA Sequencing
• Determining the base-
by-base order of the
nucleotides in a stretch
of DNA.
• Can help us identify
regions of DNA that
contain genes.
23. DNA Sequencing
• Makes possible comparisons of DNA
sequences
– between individuals to teach us about our
susceptibility to disease.
– between species to teach us about how we
evolved.
• Also, DNA sequences teach us about the
regulation of gene expression.
24. Human Genome Project (HGP)
• Overall goal:
– decipher the full set
of genetic
instructions in
human DNA.
– Develop a set of
instructions as a
research tool for
scientists.
25. Human Genome Project (HGP)
• Several genomes of
model organisms
have been
sequenced as a part
of the project.
26. What We Have Learned From
Human Genome
• First lesson:Human DNA consists of 3
billion base pairs
– Contain 20,000-25,000 genes
• 2-3 times as many genes as a worm or fruit
fly.
• Approximately 3% of DNA contains the
information to make proteins.
27. What We Have Learned From
Human Genome
• Second lesson: a greater understanding of
genes themselves.
– Has important implications to understanding
human biology and what goes wrong in disease
states.
– Help us define disease states and predict
possible candidates who are likely to suffer
from a disease based on their nucleotide
sequences.
28. What We Have Learned From
Human Genome
• Third lesson: lessons about the human
family; both our diversity and evolution.
– Compare base-by-base sequences of DNA
• Any group of individuals have DNA sequences that
are 99.9% identical regardless or origin or ethnicity.
• Points in DNA sequence where the sequences are
not identical between two or more individuals are
called single nucleotide polymorphisms (SNPs)
29.
30. HPG has Raised Ethical, Social
and Legal Issues
• Who owns genetic
information?
• Should people be
tested for genetic
disorders if there is no
possibility of
treatment?
31. How Do We Use Biotechnology?
• Gene therapy:
treatment of a genetic
disease by alteration of
the affected person’s
genotype, or the
genotype of the
affected cells.
32. Stem Cells
• Definition: undifferentiated cells in either
an adult or embryo that can undergo
unlimited number of cell divisions.
– Are totipotent
• Could be used to produce complex human
tissues or replacement organs for people
suffering from disease.
33.
34. Designer Drugs
• Biotechnology has made it possible to predict the
precise shape of molecules.
– Makes it possible to develop drugs for
therapeutic use.
35. DNA in The Courtroom
• Can be use to determine paternity
• Identifying individuals in criminal and civil
proceedings.
• Use variable number tandem repeats (VNTR) as
markers.
37. Biotechnology on The Farm
• Goal: To increase the
world’s food
production while
decreasing the costs
and environmental
damage due to
insecticide and
pesticide use.
38. Biotechnology on The Farm
• Scientists have focused efforts on three areas:
– Developing crops capable of fending off insect
pests without the use of insecticides
– Engineering plants with a greater yield that grow
in a wider ranges of climates
– Make crops that are resistant to herbicides , so that
fields can be treated for weeds without damaging
crops
• Opponents wondering if we are disturbing
ecological balance in the environment
39. Can Biotechnology Save The
Environment?
• Bioremediation: Use
of microorganisms to
decompose toxic
pollutants into less
harmful compounds.
40. Risks of Biotechnology
• Two categories of
risks:
– Risks to human
health
– Risks to the
environment
41. Questioning The Ethics of
Biotechnology
• Privacy and ownership of genetic
information.
• Argue altering genes is unnatural.
– Breaches fundamental boundaries between
species.
• Are scientists interfering with the order of
life?
