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Probing Question
• Throughout history humans were not always able to extract DNA and physically manipulate it. How did people in past overcome this obstacle?
Biotechnology
• Application of biological science to solving practical problems
• Two Methods:I. Breeding Strategies A. Selective Breeding/Artificial Selection
- indirect manipulation of DNA- select parents with desirable traits
- goal-directed: create “better” individual- oldest way to improve a species- breed
The Evolution of Corn
• 10,000 years ago ancient farmers in Mexico choose which kernels (seeds) to plant
• Noted not all plants were the same- size, taste of kernels, ease to grind
• Over time Maize cobs became larger, more rows of kernels
Maize cobs uncovered by archaeologists show the evolution of modern maize over thousands of years of selective breeding. Even the oldest archaeological samples bear an unmistakable resemblance to modern maize.
Photo © Robert S. Peabody Museum of Archaeology, Phillips Academy, Andover, Massachusetts. All Rights Reserved.
Genetic Archaeology
• Corn’s wild ancestor is a grass called teosinte
Types of Selective Breeding1. Inbreeding
- to maintain traits in a population
- mate parents with similar genomes
- keeps desirable traits, but increases risks for undesirable mutations
2. Outbreeding (Hybridization)
- crossing of distantly related organisms
- offspring often sterile but hardier (hybrid vigor)
- in nature hybrids can often survive where parents cannot; they find a different niche
Mule
Male lion and tigress = ligerMale tiger and lioness = tiglon
Sea Life Park Hawaii RECOMMEND
A wholphin (dolphin-false killer whale) named Kekaimalu.
A Fullblood Beefalo is an animal containing 3/8 American Bison and 5/8 domestic cattle. This combination produces a fertile animal which develops rapidly and provides excellent table meat.American Beefalo cattle combine the hardiness of the Bison with the temperament of bovine breeds. The bovine bloodlines can be of any breed enabling a Beefalo breeder to select the bovine genetics best fitted to his individual program.
Broccoflower
Killed by a hunter last month in the Canadian Arctic, this male bear was confirmed via DNA analysis last week to be half grizzly, half polar bear. John Roach for National Geographic News
May 16, 2006
Photograph from Canadian Wildlife Service/AP
“Some biologists estimate that as many as 10 percent of animal species andup to 25 percent of plant species may occasionally breed with another species.” NYT 9.14.10
What is the biological species concept?If hybrid is fertile and survives…
B. Other “Breeding” Options1. Use of Mutagens (Mutagenesis)- radiations or chemicals to cause mutations- used in bacteria2. Induced Polyploidy- chemical which causes cells to have extra set of
chromosomes- fruits, flowers, and plants larger- *some cases such as plants and lower animals natural occurrence - lethal for human zygote
II. Genetic Engineering- direct manipulation of DNA- cutting and pasting of genes- design organisms or create transgenic organisms- transgenic organism- organism with foreign DNA or rDNA- recombinant DNA (rDNA)- DNA molecule made of DNA fragments from two different species (ex. Bacteria and human)
- vector- agent/vehicle used to transport rDNA or gene of interest into organisms
Using recombinant DNA technology we can make
transgenic…
• Bacteria
• Plants
• Animals
How do you feel about genetically altering a species from its normal state?What useful applications of this biotechnology exist?
Which transgenic species will prevail as the leader in biosteel production?
SPIDERGOAT?
STEELYSILKWORM?
Steps involved in creating spider-goats:
1. Identify the genes associated with “silk”production.
2. Genetically engineer (clone) the genes
3. Implant genes into embryo of the goat
Figure 6.28Microinjection of DNACloned plasmid DNA is being microinjected into the male pronucleus of a fertilized mouse egg.From: Section 6.3, Manipulating the Genes of Eukaryotes
A DNA construct can be injected into 0.5-day-old fertilized embryos to produce transgenic mice containing the DNA in every cell. The DNA construct typically consists of a gene of interest that is expressed in a certain range of tissues. The resulting mice are mated and the DNA construct is then transmitted to offspring.
Rat Growth Hormone-Metallothionein Gene Construct. The gene for rat growth hormone (shown in yellow) was inserted into a plasmid next to the metallothionein promoter, which is activated by the addition of heavy metals, such as cadmium ion.
http://www.ncbi.nlm.nih.gov/books/NBK22390/
Spider-goats continued…
4. Lactation
5. Distillation
6. Purification
7. Spinning
8. Stretch the fiber
In groups…
• Discuss questions and record your answers your notebook.
• Add the following question, “Is silk production in goats an acceptable use of biotechnology?”
As you watch each of the following record your thoughts
and/or questions.
Human anti-clotting Protein produced in the goat’s milk
Engineered mice with green fluorescent protein
Engineering rainbow trout to increase their muscle mass
Are these instances acceptable uses of biotechnology?
Biomimicry- the study of genetically manipulating one species to have a specific
trait of another species.• What are the various uses for goat silk that were
described in the video? Explain how the silk would be effective for each use?
• Why is it not practical to use spider farms to harvest the silk fibers?
• Is silk production in goats an acceptable use of biotechnology?
• Has your opinion of genetically altering a species changed?
What information needs to be known up front?
Transgenic Animals
Recombinant DNA can be introduced by:
1.DNA microinjection
2.Retrovirus mediated gene transfer
Steps to Make a Transgenic Bacterium
1. DNA Extraction- get genome from organism containing gene of interest
2. Splice gene of interest from genome using a restriction enzyme(RE)
- RE, chemical that cuts DNA at a recognition site(short sequence of bases)
3. Splice bacterial plasmid using same RE
- plasmid: circular piece of DNA in bacteria video clip
Plasmid may not
be exactly circular
http://www.ncbi.nlm.nih.gov/books/NBK22390/
Making recombinant plasmid(DNA)
Red= bacteria DNABlue= human insulin gene
- Details making recombinant plasmid (DNA)
a. Due to sticky ends, gene can be spliced in
b. DNA ligase help nuclotides bond
c. Combined DNA called rDNA or chimera
d. Put rDNA back into bacteria and grow in culture
Insertion of Gene of Interest into Plasmid
Using rDNA plasmid to create a transgenic plant
A virus is another biological vector also used to deliver genes
IF you had to genetically engineer a bacteria to to transport a gene into a tobacco plant, which
would you choose?
Mechanical Vectors:
1. Gene Gun
2. Pipette
http://www.agriculture.purdue.edu/agbiotech/images/Genegun1.html
Transgenic Organisms
GOAT GOODS. A transgenic goat named Artemis produces in her milk a human-breast–milk compound called lysozyme. Lysozyme destroys bacteria by drilling through their cell walls.E. Scharfen
3. Gel Electrophoresisa. Method of separating DNA fragments according to their size
b. DNA slightly (-) charge, will run towards (+) charge
c. Shorter DNA fragments will move farthest
d. Check to see if DNA was cut by RE
