genetic technologies
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Genetic Technologies Chapter 8
Genetic Engineering Intent of altering human genome Introducing new genetic material into
genome Insulin
Recombinant DNA DNA that contains genes of two species How?
› Restriction enzymes – cut out desired gene› Occur naturally in prokaryotic cells › Recognize specific recognition sites – 4 to 8 base pairs› Recognition sites are palindromes › Cuts gene (digests) in one direction only› Creates restriction fragments
Process – Restriction Enzyme
Locates recognition site (Top Strand)
Cuts the DNA backbone
Locates recognition site (Bottom Strand)
Cuts the DNA backbone
DNA separates
Sticky Ends or Blunt Ends
Sticky ends – zigzag cuts in strand Blunt ends – straight cut across strand
Putting Fragments together DNA ligase – sticky ends T4 DNIA ligase – blunt ends
› forms phosphodiester bonds in DNA
Plasmids
Small circular pieces of DNA found in bacteria Used as vectors for recombinant DNA (artificial) Restriction enzymes used to isolate specific
gene are used to cut plasmids
Process Plasmids and DNA
fragments are placed in same solution
Anneal DNA ligase is used
to form phosphdiester bond
Recombinant DNA introduced into host cell
DNA is cloned
Restriction Maps Diagrams that show all recognition sites on
a specific plasmid and distances in base pairs
Shows which restriction enzyme should be used
Allow scientists to determine which plasmids will work the best for cloning experiments
Transformation Cells that receive foreign DNA Bacterial cells sometimes will not take up a plasmid Bacteria are placed in ice water bath containing
CaCl₂ Solution is heated and cooled repeatedly disrupting
plasma membrane of bacteria allowing plasmid to enter
Solution is kept at 37⁰C to stabilize and grow
Identifying Bacteria Clones with Target Genes
Hybridization – identify cells that contain recombinant DNA
Identified using a hybridization probe – short single stranded complementary DNA molecule
Once identified bacteria can be grown in huge quantities (commercial use)
PCR Polymerase Chain Reaction
› Increase number of DNA copies from a single biological sample in a few hours
› Only specific regions of a chromosome are replicated
Process› Denaturation› Annealing› Elongation
Taq polymerase is used to put strand together
Isolated from bacteria that live in hot springs
Gel Electrophoresis
Technique used to separate fragments of DNA (PCR)
Genetic Engineering Biopharming
› Pharmaceutical products produced on large scale › Organisms are genetically engineered to produce
a specific protein › Ability to make new protein is passed on to
offspring
Genetic Engineering
Transgenic Organism (genetically modified organism, GMO)› Organisms that contain one or more genes from
another organism
Why use Genetic Engineering? Cost Larger organisms can
produce larger molecules
Better versions of organisms
80% of Canadas Canola crop is GM
Knockout Mice
Concerns?
Gene Therapy Techniques used to replace, remove or
alter a defective gene before symptoms are expressed
Gene Therapy Germ-line gene
therapy› Genes introduced
in sperm or egg cells
› Passed on to future generations
Somatic gene therapy› Genes introduced
into body cells (not sperm or egg)
› Will not be passed on
Genetic Screening To detect any mutation in DNA that is
associated with a genetic disorder (huntingtons disease)
Aminocentesis› Prenatal screening
Cord Blood (CBE) Source of hematopoietic (blood forming)
stem cells Can be used to treat and cure disease and
other conditions
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