
Process of manipulating genes for
practical purposes.

Process in which biologists make
changes in the DNA code of a living
organism.

A technology in which the genome of a
living cell is modified for medical or
industrial use.

Genetic engineering can involve
building recombinant DNA.

DNA molecules that are artificially made
from two or more different organisms.
Steps in a genetic engineering
experiment
 Please
look over the 4 steps in a
genetic engineering experiment
on page 229.

DNA from the organism containing the gene
of interest is cut by
are enzymes that destroys
foreign DNA molecules by cutting them at
specific sites.
are bacterial enzymes
that recognize and bind to specific short
sequences of DNA, and then cut the DNA
between specific nucleotides within the
sequence.

The DNA from a vector is also cut.

Vector – is an agent that is used to carry the
gene of interest into another cell.
› Commonly used vectors include:
 Viruses
 Yeast
 Plasmids – from bacterial cells
Plasmid are circular DNA molecules that can
replicate independently of the main chromosomes
of bacteria

The DNA fragments from the organism
containing the gene of interest are
combined with the DNA fragments from
the vector.

The host cells then take up the
recombinant DNA.

Gene Cloning – many copies of the
gene of interest are made each time the
host cell reproduces

Remember that bacteria reproduce
asexually by binary fission so it produces
identically offspring.

Cells that received the particular gene
of interest are distinguished, or
separated, from the cells that did not
take up the gene of interest.

The cells can transcribe and translate the
gene of interest to make the protein
coded for in the gene.
 Gel
electrophoresis
 RFLP
 PCR
Analysis
– Polymerase Chain
Reaction

Technique that uses an electric field within a gel to
separate DNA molecules by their size.

DNA fragments are placed at one end of a porous
gel and an electric voltage is applied to the gel.
Restriction enzymes
cut DNA into
fragments
The DNA fragments
are poured into wells
on a gel.
The electric voltage is
applied to the gel.
The smaller the DNA
fragment, the faster
and farther it will move
across the gel.
 The
polymerase chain
reaction (PCR) is a scientific
technique in molecular
biology to amplify a single or a few
copies of a piece of DNA across
several orders of magnitude,
generating thousands to millions of
copies of a DNA .

A method of making many copies of a
piece of DNA

Restriction fragment length
polymorphism or RFLP analysis is used to
identify a change in the genetic
sequence that occurs at a site where a
restriction enzyme cuts.

RFLPs can be used to trace inheritance
patterns, identify specific mutations, and
for other molecular genetic techniques.
Forensics
Gene therapy:
the insertion, alteration, or removal of genes
within an individual's cells and biological
tissues to treat disease.
Vaccines
Through the recombinant-DNA
procedure, it is now possible to transfer
the genes that stimulate antibody
formation to a harmless microorganism
and use it as a vaccine against the
particular disease. Vaccines have been
successfully created using the harmless
cowpox virus, the herpes simplex type I
virus (cold sores), the influenza virus, and
the hepatitis B virus through gene
splicing.
Genetically
Modified Crops
Cloning
A clone is a member of
a population of
genetically identical
cells produced from a
single cell.
In 1997, Ian Wilmut cloned a
sheep called Dolly.
Transgenic Organisms
 An organism described as transgenic, contains
genes from other species.
Transgenic Microorganisms
 Transgenic bacteria produce
important substances useful for
health and industry. Transgenic
bacteria have been used to
produce:
 insulin
 growth hormone
 clotting factor
Transgenic Plants
 Transgenic plants are now an
important part of our food supply.
 Many of these plants contain a
gene that produces a natural
insecticide, so plants don’t have to
be sprayed with pesticides.
Transgenic Animals
 Transgenic animals have been used to study
genes and to improve the food supply.
 Mice have been produced with human
genes that make their immune systems act
similarly to those of humans. This allows
scientists to study the effects of diseases on
the human immune system.
 Researchers are trying to produce transgenic
chickens that will be resistant to the bacterial
infections that can cause food poisoning.