Transcript DNA TECHNOLOGY - Mount Mansfield Union High School

DNA TECHNOLOGY
Developments and Applications
Genetic Engineering
• Modifying an organism’s genotype by
introducing genes that have never been
present in the chromosomes of that
particular species.
HISTORY
• 1952- Birth of a calf by artificial insemination (AI)
• 1953- Watson & Crick’s model of DNA
• late 1960s- Restriction enzymes in E. coli were
discovered to 'cut' DNA at specific sites.
• 1969- Harvard Medical team first to separate a gene
from DNA
• 1972- First animal born from frozen embryo
• 1973- First use of restriction enzymes to insert DNA
into a plasmid and make many copies of the DNA.
• 1977-Walter Gilbert and Frederick Sanger worked
out methods to determine the sequence of bases in
DNA
History (cont.)
• 1978- Birth of Louise Brown-- the first 'test-tube'
baby born from in vitro fertilization (IVF)
• 1979- First production of insulin through genetic
engineering.
• 1980- First transgenic (genetically modified) mouse.
• 1982- Giant mouse produced by transferring growth
hormone genes from a rat
• 1983- First transgenic plant (tobacco)
• 1984-Birth of a baby from an embryo which had been
stored frozen and development of DNA fingerprint.
• 1988- First transgenic plant producing a
pharmaceutical & first animal patented (oncomouse)
by Harvard Univ.
Transgenic OrganismAn organism
whose genome
has been
modified by
introduction of
novel DNA
Transgenic Plants
“Glowing” Transgenic Plants
This "autoluminograph" of a glowing transgenic tobacco plant
bearing the luciferase gene of a firefly was first done in 1986
More History
• 1990- Human Genome Project started
• 1991- first gene therapy trials on humans
• 1992- US military begins collects blood samples of all
soldier to serve as genetic “dog tags”
• 1994- first transgenic tomatoes sold in stores (with
softening inhibition gene)
• 1997- Dolly was born (first animal cloned by nuclear
transfer using a mammary cell from an adult sheep as
nucleus donor and an enucleate ovum as recipient).
 1998 - Researchers first extract stem cells from human
embryos
• 1999- First publicly reported human death from gene
therapy.
2000’s
• 2000- Human genome draft completed
• 2001
– Birth of first genetically modified primate, a rhesus monkey
named ANDi (inserted DNA backwards) and containing a
fluorescent marker gene from a jellyfish, at Oregon Regional
Primate Research Centre, USA
– Publication in the journals Nature and Science of the first draft of
the human genome estimated to be between 26,000 and 40,000
genes.
– President Bush restricts federal funding for embryonic stem-cell
research
• 2002- First cloned cat (cc)
• 2003- Dolly is euthanized after developing lung disease
• 2004– South Koreans claim first cloned human
– Harvard researchers grow stem cells from embryos w/ private $
• 2005- South Koreans exposed for lying about human clone
• 2009- Obama overturns stem cell ban, but opposes human cloning
timeline
Recent News
• In 2006, a team of scientists found a way to extract embryonic stem
cells without destroying the actual embryo.1
–
This would enable scientists to work with new lines of embryonic stem cells derived using public
funding.
• In 2007, two research teams announced a similar breakthrough with
ordinary human skin cells that were transformed into cells that look
and act like embryonic stem cells. 2
–
However, the genes used to reprogram the skin cells were added by the use of
retroviruses that can cause mutations and possibly lead to the risk cancers.4
• In 2007 a research team at the Whitehead Institute claimed to cure
mice of sickle cell anemia. 3
• In 2008, a California based company, Stemagen, announced that they
had created the first mature cloned human embryos from single skin
cells taken from adults.5
1.
Klimanskaya I, Chung Y, Becker S, Lu SJ, Lanza R. (2006). "Human embryonic stem cell lines derived from single blastomeres.". Nature
444 (7118): 481-5. PMID 16929302. 2 "Embryonic stem cells made without embryos", Reuters, November 21, 2007.
3 Rick Weiss. "Scientists Cure Mice Of Sickle Cell Using Stem Cell Technique: New Approach Is From Skin, Not Embryos", Washington Post,
December 7, 2007, pp. A02.
4 "Researchers get closer to safe stem cell treatments", AFP, February 14, 2008.
5 Helen Briggs. "US team makes embryo clone of men", BBC, January 17, 2008, pp. A01.
More Recent News
• January 23, 2009-- National Geographic reported the use of
frozen skin in 2003 to clone a Pyrenean ibex, a subspecies of
Spanish ibex that went extinct in 2000.
– Real-life Jurassic Park?
– "The public should not leap to the conclusion that we are on the edge of cloning
woolly mammoths or dinosaurs," he said. "Even if such embryos could be
constructed, there are no appropriate surrogate mothers for long-dead species."
• March 9, 2009-- Obama Says Government Will Not Open the
Door for Human Cloning
– President Obama says the government will not open the door for human
cloning, as he signed an order lifting restrictions on federal funding for
embryonic stem cell research.
• November 22, 2010: Advanced Cell Technology Wins FDA Approval
To Test Stem Cell Therapy For Degenerative Eye Disease
– Regenerative medicine company received federal approval from the US
FDA to begin a multi-centre clinical trial that tests human embryonic stem
cell treatment on patients with Stargardt’s Macular Dystrophy,
What’s new in applied genetics?
•
*Video “President Obama on Stem Cell
Research”
ViaGen: Preserving your Pets Service
RECOMBINANT DNA
• molecules that contain DNA sequences derived
from different biological sources that have been
joined together in the laboratory.
Genetically engineered food:
•Insecticide sweet corn- Scientists have genetically modified
sweet corn so that it produces a poison which kills harmful
insects.
•Golden rice – large amounts of vitamin A from gene in carrots
adds nutrients to rice.
•Frostban strawberries- protects strawberries from natural
bacteria that cause frost to form
•Pesitcide resistant plants- When the farmer sprays his
genetically modified crop with pesticides, he or she can destroy
most of the pests without killing the plants
Genetically engineered
animals:
• Mice with human proteins- like
oncomouse (has a gene for cancer)
• Pharming- livestock have been
produced that express foreign proteins
in their milk (like Factor IX or insulin).
– A pig expressing human protein C (a clot-busting drug) in
its milk is worth about $1,000,000 per year.*
• AquaAdvantage© Salmon – grow from
egg to market size in half the time
*”Pig-napping may become a more common crime, as the pharming
develops”
from http://www.escience.ws/b572/L21/L21.htm
VOCAB to KNOW for this Unit
TRANGENIC- an organism that carries a foreign gene that has been
deliberately inserted into its genome.
SPLICING– inserting the gene in question into a larger molecule of DNA
•VECTORtransport vehicle which
carries the desired gene
into the host cell.
•PLASMIDa small circular DNA molecule
found in bacteria (separate from
the main bacterial
chromosome).
More Vocab
• RESTRICTION ENZYME- - a
special DNA-cutting enzyme
that is found in bacteria
• DNase- eukaryotic DNAdigesting enzymes
• DNA LIGASE- an enzyme that
seals the gaps in the DNA
• DNA CLONING- making many
copies of DNA (amplification)
through the use of a host
bacterial cell
And still some more Vocab……
• RESTRICTION FRAGMENTS- Pieces of DNA of varying
lengths
•GEL ELECTROPHORESIS- DNA fragments move through
a porous gel in response to an electric current (small = fast)
•DNA PROBE- a single-stranded DNA fragment that
possesses a particular sequence which is complementary
to the fragment being sought. Sort of like a guided missile.
POLYMERASE CHAIN REACTION (PCR)- a way of
amplifying a single region of DNA using DNA polymerase
and heat.