Ch 20. Biotechnology Guided Notes
Terms to Know:
1. Genetic engineering: process of manipulating genes and genomes
2. Biotechnology: process of manipulating organisms or their components for the purpose of making useful products.
3. Recombinant DNA: Recombinant DNA: DNA that has been artificially made, using DNA from different sources. eg.
Human gene inserted into E.coli
4. Gene cloning: process by which scientists can product multiple copies of specific segments of DNA that they can then
work with in the lab
5. Restriction enzymes
6. Sticky ends
7. DNA ligase
8. Cloning vector
9. Nucleic acid hybridization
10. Genomic library
11. cDNA library
12. PCR
13. Gel electrophoresis
14. Southern blotting
15. DNA microarray assays
16. SNPs
17. RFLPs
18. Stem cells
19. Gene therapy
20. GMO (genetically modified organism)
What you Must Know:
 The terminology of biotechnology.
 The steps in gene cloning with special attention to the
biotechnology tools that make cloning possible.
 The key ideas that make PCR possible.
 How gel electrophoresis can be used to separate DNA
fragments or protein molecules.
1. Tools of Genetic Engineering
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
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Restriction enzymes (restriction endonucleases): used to
cut strands of DNA at specific locations (restriction sites)
o Restriction Fragments: have at least 1 sticky
end (single-stranded end)
o Using a restriction enzyme (RE) and DNA ligase to
make recombinant DNA
DNA ligase: joins DNA fragments
Cloning vector: carries the DNA sequence to be cloned
(eg. bacterial plasmid)
2. Gene Cloning and Application
3. Techniques of Genetic Engineering
 Transformation: bacteria takes up plasmid (w/gene of interest)
 Nucleic acid hybridization: used to track gene of interest



PCR (Polymerase Chain Reaction): amplify (copy)
piece of DNA without use of cells
Gel electrophoresis: used to separate DNA
molecules on basis of size and charge using an
electrical current (DNA  + pole)
Southern blotting: used to find a specific human
gene
 DNA microarray assays: study many genes at
same time
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
Cloning Organisms
Nuclear transplantation: nucleus of egg is
removed and replaced with nucleus of body cell
4. Problems with Reproductive Cloning
 Cloned embryos exhibited various defects
 DNA of fully differentiated cell have epigenetic changes
5. Stem Cells
 Stem cells: can reproduce itself indefinitely and
produce other specialized cells
 Zygote = totipotent (any type of cell)
 Embryonic stem cells = pluripotent (many cell
types)
 Adult stem cells = multipotent (a few cell
types) or induced pluripotent, iPS (forced to
be pluripotent)
6. Applications of DNA Technology
 Diagnosis of disease – identify alleles, viral
DNA
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
Gene therapy – alter afflicted genes
Production of pharmaceuticals
o Pharm” animal: produce human
protein secreted in milk for medical use
 Forensic applications – DNA profiling
 Environmental cleanup – use
microorganisms
 Agricultural applications – GMOs
7. RFLPs (“rif-lips”)
 Restriction Fragment Length Polymorphism
 Cut DNA with different restriction enzymes
 Each person has different #s of DNA fragments created
 Analyze DNA samples on a gel for disease diagnosis
 Outdated method of DNA profiling (required a quarter-sized sample of blood)
8. STR Analysis
 STR = Short Tandem
Repeats
 Non-coding DNA has
regions with sequences
(2-5 base length) that
are repeated
 Each person has different
# of repeats at different
locations (loci)
 Current method of DNA
fingerprinting used –
only need 20 cells for
analysis
Ch. 21 Genomes and Their Evolution
What you Need to Know:
•
•
•
•
•
The major goals of the Human Genome
Project
How prokaryotic genomes compare to
eukaryotic genomes.
The activity and role of transposable
elements and retrotransposons.
How evo-devo relates to our
understanding of the evolution of
genomes.
The role of homeotic genes and
homeoboxes.
1. Human Genome Project
 Purpose: to sequence the entire human
genome
 Completed in 2003
 >1,200 genomes sequenced now (1000
bacteria, 80 archaea, & 124 eukaryotic
species)
2. Human DNA
• 3 billion base pairs
• ~20,000 genes
• Only 1.5% codes for proteins (or RNA)
• Repetitive DNA: sequences present in
multiple copies
3. Transposable Elements
 Make up 75% of repetitive
DNA
 Can be moved from one
location to another in
genome
 Discovered by Barbara
McClintock – corn breeding
experiments
 2 Types:
 Transposons
 Retrotransposons
4. Transposons
 Moves within genome via DNA
intermediate
 “cut & paste” or “copy &
paste” mechanisms
 Requires enzyme transposase
5.
Retrotransposons

Move by means of RNA
intermediate

Leaves copy at original site

Involves enzyme reverse
transcriptase
6.
Genome Evolution
 Duplication  genes with related
functions
 Genes diverge by accumulating
mutations
 Some become nonfunctional
pseudogenes
 Eventually, new genes with new
functions can occur
7. Multigene Families
 Collections of 2 or more identical or very
similar genes
 Eg. hemoglobin: -globin and -globin
gene families
8. Illustrative Example: Antifreeze Gene in fish
 Antifreeze proteins (AFP): produced by vertebrates, plants, fungi, bacteria to aid survival in sub-zero environments
 Function: bind to ice crystals and prevent growth
 Antarctic fish: old protein gene transformed into a new gene with new structure/function
 Gene mutates  duplicated  divergent evolution
9. Transpositions  Chromosomal Rearrangements
10.
Transposable Elements Contribute to Evolution
 Promote recombination, disrupt genes or control
elements, & carry genes to new locations
 May be harmful or lethal, but can also have small
beneficial effects
 Provides raw material for natural selection
11.
Evolutionary Development (Evo-devo)
• Compares developmental processes to understand how
changes can lead to evolution of organisms
12. Homeotic Genes
 Homeotic genes: master regulatory genes
o

Control placement and spatial
organization of body parts
Homeobox: widely conserved 180nucleotide sequence within homeotic (Hox)
genes
o
o
Found in many groups (fungi, animals,
plants)
Hints at relatedness between all life
forms