|
Summary |
|
Questions |
|
Media
Resources |
|
19.1 The ability to
manipulate DNA has led to a new genetics.
|
|
• Genetic
engineering involves the isolation of specific genes and their transfer
to new genomes.
• An important component of genetic engineering technology
is a special class of enzymes called restriction endonucleases, which
cleave DNA molecules into fragments.
• The first such recombinant DNA was made by Cohen and
Boyer in 1973, when they inserted a frog ribosomal RNA gene into a bacterial
plasmid.
|
|
1. Why
do the ends of the DNA fragments created by restriction endonucleases
enable fragments from different genomes to be spliced together?
|
|
|
|
19.2 Genetic engineering
involves easily understood procedures.
|
|
• Genetic
engineering experiments consist of four stages: isolation of DNA, production
of recombinant DNA, cloning, and screening for the gene(s) of interest.
• Preliminary screening can be accomplished by making
the desired clones resistant to an antibiotic; hybridization can then
be employed to identify the gene of interest.
• Gene technologies, including PCR, Southern blotting,
and RFLP analysis, enable researchers to isolate genes and produce them
in large quantities.
|
|
2. Describe
the procedure used to eliminate clones that have not incorporated a vector
in a genetic engineering experiment.
3. What is used as a probe in a Southern blot? With what
does the probe hybridize? How are the regions of hybridization visualized?
|
|
|
|
19.3 Biotechnology
is producing a scientific revolution.
|
|
• Extensive
research on the human genome has yielded important information about the
location of genes and the comparisons of the human genome with other organisms.
·Biochip technology, also called gene microarray, will expand the
analysis of DNA.
· Gene splicing holds great promise as a clinical tool, particularly
in the prevention of disease with bioengineered vaccines.
· A major focus of genetic engineering activity has been agriculture,
where genes conferring resistance to herbicides or insect pests have been
incorporated into crop plants.
· Recent experiments open the way for cloning of genetically altered
animals and suggest that human cloning is feasible.
· The impact of genetic engineering has skyrocketed over the past
decade, providing many useful innovations for society; its moral and ethical
aspects still provide a topic for heated debates.
|
|
4. What is
the primary vector used to introduce genes into plant cells? What types
of plants are generally infected by this vector? Describe three examples
of how this vector has been used for genetic engineering, and explain
the agricultural significance of each example.
5. How is the genetic engineering of bovine somatotropin (BST)
used to increase milk production in the dairy industry? What effect would
BST in milk have on persons who drink it?
|
|
|
