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C13 Genetic Engineering
C13 Genetic Engineering
DNA:
Extraction of DNA is done by rupturing the cells and adding a
precipitating reagent such as ethanol. Then DNA can be spooled
onto a glass rod or removed with a pipette.
Cutting DNA into pieces is done with restriction enzymes. Each
one cuts DNA at a specific sequence of nucleotides.
Separating DNA can be achieved by using gel electrophoresis. In
DNA electrophoresis, the DNA cut with restriction enzymes is put into
the well at one end (negative end – black) of the gel. DNA molecules
are negatively charged and will travel to the positive end when
current is applied. The smaller fragments travel faster. We can
use this to get the DNA fingerprint or to isolate a gene we want for
further study.
Transgenic organisms are organisms with foreign DNA.
E.coli is used daily as a transgenic organism to produce human
drugs, ex. human insulin and TPA (clot buster for heart attacks).
Bacteria make great transgenic organisms because they have a tiny
circular DNA, called a plasmid, that we can remove and add back
C13 Genetic Engineering
with our gene in it. Animals also being used, like the cow that makes
milk with a human protein. Plants are important transgenic
organisms. In the year 2000, 52% of soybeans, and 25% of corn
grown in the US were transgenic (or genetically modified). Most were
modified for pesticide resistance.
Bacterial transformation steps:
1. Insertion of a gene into a bacterial plasmid
2. Getting bacteria to take in the plasmid
3. Selecting the transformed bacteria
4. Producing the product (gene to protein).
5.
Cloning – making a genetically identical organism from a single cell.
In 1997, Ian Wilmut cloned, the now deceased, Dolly from the
mammary cell of a sheep.
C13 Genetic Engineering
Stem cells – unspecialized cells (not differentiated). Remember all
body cells have all the DNA, but only use the genes to make the
proteins needed for that cell type once it becomes specialized.
Gene therapy – using genes to treat diseases, such as cystic fibrosis.
Genetically modified organisms (food) – altered so less pesticides are
needed.