Genetic Engineering, Part 1 6
Ed. pages 375-380; 383-385; also section on
agricultural applications - equivalent to 406-407 in 7
Ed. pages 384-389; 406-407.
Ed. pages 396-403; 421-423
Genetic engineering is the manipulation of genes for desired results.
learning how biological systems work (as we’ve done up until now in the course), we’ll now see
how we can use this information for our own purposes.
Other names referring to this branch of
biology are recombinant DNA technology, molecular biology, and gene cloning.
Gene cloning is
the production of many copies of a desired gene.
We’ll discuss 3 practical applications of genetic
One is to make useful products.
These include improved crops and livestock, and
also purified proteins, such as insulin for diabetics.
This is easier, cleaner, and cheaper than
purifying these proteins by conventional means.
Another application of genetic engineering is in
The information we are gaining about the function of the proteins in our bodies comes
from genetic engineering.
In addition to basic understanding of biology, research can lead to
important medical applications, including new drugs and gene therapy for genetic diseases.
of these potential applications have not yet been realized.
These are a challenge for the next
generation of biologists!
Finally, cloning genes (especially by PCR, as we'll see in the next lecture)
is useful in forensics.
Small amounts of tissue left by a criminal at a crime scene can be used to
identify the criminal.
Genetic engineering depends on bacteria
Instead of having to invent tools for genetic engineering
from scratch, we take advantage of several features of bacteria that have been perfected by billions
of years of evolution.
Bacteria are ideal for this purpose, as they are fast-growing and cheap.
can easily get bacteria to make many copies of any gene or other DNA fragment that we want.
There are 2 types of uses for these genes.
First, we can isolate these genes for further analysis.
instance, if we discover a new oncogene in a person, we may want to know what the mutation is
that makes it an oncogene.
We need many identical copies of the gene to determine its sequence
and identify the mutation.
Alternatively, we can have the bacteria express the gene and make the
An example is insulin, which people with one kind of diabetes must take daily.
having to isolate insulin from animal tissue (as was the case before genetic engineering), we can
express the human insulin gene in bacteria, have bacteria make the protein, and then purify it.
the next few paragraphs, we’ll use production of human insulin by bacteria as an example to
illustrate the steps required to get bacteria to produce a desired foreign protein.
Making recombinant insulin: the first steps