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Biotechnology
Packet #26
Chapter #9
Introduction
 Since the 1970’s, humans have
been attempted to manipulate
and modify genes in a way that
was somewhat predictable.
 Biotechnology merges biological
information with computer
technology to advance research.
 Biotechnology involves
techniques that are used to make
or modify the products of living
organisms in order to improve
plants or animals, or to develop
useful microorganisms.
Key Terms & The Making
of a Transgenic Organism
Transgenic Organism
 A transgenic organism has
had a gene(s), from another
organism, inserted into its
genome.
 The inserted genes are then
expressed to display a
specific phenotype.
Necessities for Making a
Transgenic Organism
 In order to make a
transgenic organism the
following pieces are
necessary to be
used/produced:  Donor DNA
 Restriction Enzymes
 Fragments
 Vector DNA
 Recombinant DNA
The Process in a Nutshell I—
Prokaryotic Transgenic Organism
 There are variations,
depending on what a scientist
is trying to accomplish, in the
making of a transgenic
organism.
 Scientists select a gene, from
a donor, to be inserted into a
different organism.
 The gene of choice, found
within/on the DNA molecule,
would be cut out, using
restriction enzymes, to
produce a fragment.
The Process in a Nutshell II—
Prokaryotic Transgenic Organism
 The fragments are spliced
into vector DNA—producing
recombinant DNA.
 DNA ligase is used to join the
DNA fragment together with
the vector’s genome.
 Vector DNA is normally a
plasmid.
 The plasmid, now in the form
of recombinant ,is inserted
into bacterial cell.
 The bacterial cell is replicated
producing a transgenic
organism.
The Process in a Nutshell III—
Eukaryotic Transgenic Organisms
 One way of producing a
transgenic eukaryote would
involve:  Inserting bacteria, or viral,
organism, containing the
recombinant DNA, into the
organism into eukaryote.
 Waiting until the eukaryotes
genome has been changed
by the invading
bacteria/virus.
The Process in a Nutshell IV—
Eukaryotic Transgenic Organisms
 A second technique for
producing a transgenic
eukaryote would involve:  Isolating a gene
 Inserting the gene into a
totipotent stem cell.
 Placing the stem cell(s) into a
blastocyst.
 Blastocyst = ball of cells
during early stages of
embryonic development
 Placing the blastocyst, with
embryonic stem cell
containing inserted DNA
fragment, into uterus.
Purpose of Recombinant DNA
 Recombinant DNA
technology isolates and
amplifies specific
sequences.
 Amplification can be
accomplished by making
more of the transgenic
organisms.
 Accomplished via organism
reproduction
 Cloning.
The Importance of
Transgenic Organisms
The Importance of Transgenic
Organisms
 Transgenic organisms allow
gene targeting and
mutagenesis screening that
help identify the function of
a gene and its protein
product.
Cloning
Cloning
 Cloning is the generation of
genetically identical
organisms
Genomics & Genetic
Libraries
Genomic Library & cDNA Library
 Genomic Library
 DNA library containing an
organism’s complete genome
 In the form of thousands of
DNA fragments
 cDNA Library
 DNA library made up of “DNA
clones” reconstructed using
reverse transcriptase
 Must be made from mRNA
 Genomics
 Sub-discipline in genetics of
characterizing the entire
genomes of organisms.
Homework Assignment
 What are some of the advantages, and disadvantages, of
having a cDNA library?
Genetic Probes
Genetic Probes
 Genetic probes are
radioactively labeled DNA
or RNA sequence that
enables geneticists to
identify complementary
nucleic acid sequences.
 If used to identify a DNA
strand, the DNA molecule
will have to be separated
into into two strands via
artificial denaturation—
heat.
The Making of Genetic Probes
Southern Blot Technique
 DNA fragments, produced
using restriction enzymes,
are separated via gel
electrophoresis.
 Fragments are blotted onto
a nitrocellulose or nylon
membrane.
 The membrane is bathed in
a labeled probe for a specific
DNA fragment.
 The selected DNA fragments
are cut out of the gel
Homework Assignment
 Define Northern Blot.
 Define Western Blot.
Making Copies of DNA in
a Lab Setting
Introduction
 Once a sequence of DNA (DNA fragment) has been
isolated, it is sometimes necessary to make large amounts
of that sequence for study.
Polymerase Chain Reaction
 Allows rapid, efficient
amplification of DNA
sequences of interest.
 In vitro technique
 Researchers target a
particular DNA sequence, by
specific primers, and then
clone the DNA sequence by
heat resistant DNA
polymerase.
 Used to help amplify DNA
from crime scenes and
archaeological remains
Gene Therapy
Gene Therapy
 Simple idea—hard to
practice
 The use of sequencing,
cloning and vector insertion
techniques to
 Deliver working versions of
genes to individuals who are
born with deleterious
mutant versions of the gene.
 Germ Line Therapy
 Somatic Gene Therapy
Genetic Engineering &
Food
Genetic Engineering of Agricultural
Species
 Foreign genes, under study, for
insertion into commercial plant
species. Helps provide
 Selective herbicide resistance
 Increased yield
 Plant-grown vaccines and
pharmaceuticals
 Improved nutrient balance
 Problems?
 Human allergic reactions to
foreign proteins
 Increased use of herbicides
 “jumping” of plasmids from
commercial crops to weed species.
 Eco-mayhem!
Review