Biotechnology and Genetic Engineering

- What is it?- electrophoresis- PCR- the Human Genome Project

DNA sequencing-Cloning (genes),

chapter 9

What is it?

biotechnologynoun: “the use of living organisms or other biological systems in the manufacture of drugs or other products or for environmental management, as in waste recycling: includes the use of bioreactors in manufacturing, microorganisms to degrade oil slicks or organic waste, genetically engineered bacteria to produce human hormones, and monoclonal antibodies to identify antigens.”

Random House Unabridged Dictionary

There is WAY more included than the examples listed here.

1.

genetic engineering1. the development and application of scientific methods, procedures, and technologies that permit direct manipulation of genetic material in order to alter the hereditary traits of a cell, organism, or population.

2. a technique that produces unlimited amounts of otherwise unavailable or scarce biological product by introducing DNA isolated from animals or plants into bacteria and then harvesting the product from a bacterial colony, as human insulin produced in bacteria by the human insulin gene.

Electrophoresis

- restriction endonucleases recognize specific sequences

-The digests are run on a gel: electrical current pulls fragments smaller pieces go further

- May be used fordiagnosis,paternity testing,criminal forensics,to purify a section of DNA needed for further study.

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- Can be used (with different matrices) to separate proteins and other molecules as well as DNA. →

application: DNA fingerprinting (Here, paternity testing)

http://www.thetech.org/genetics/ask.php?id=20

A selected segment of (usually)“junk” DNA is isolated ←RFLP: restriction fragment length polymorphism (“riflips”), usually due to variable STR: short tandem repeats

←The RFLP patternis established forthe persons ofinterest….and compared to the child’s pattern:He had to get thoserestriction sitesfrom his parents. →

Consequences of DNA fingerprinting (DNA profile):What are the implications for paternity testing?

There are historical applications, too.How might it be medically important?

In forensics,the evidence is much stronger than eye witnesses, cold cases are often resolved in the alleged perp’s favor…

CODIS (Combined DNA Index System) files: pros and cons… as it were.(in 1999 180,000 rape kits were unprocessed.*)

* for more info, NIJ report 7/2002:http://www.ncjrs.gov/pdffiles1/nij/194197.pdf

PCR: polymerase chain reaction-used to amplify DNA samples for fingerprinting, sequencing,or further genetic manipulation.

- isolate segment of interest- warm to denature- cool to anneal primer- allow polymerase to proceed- Each cycle doubles the DNA.

DNA from as few as 20 cells can be enough to use PCR and catch a criminal.

This technology was anessential starting point for ….

the Human Genome Project

Started in 1990, finished in 2003 (way ahead of schedule, due to technology and competition issues),

for disease diagnosis, genetic research, evolution studies, possible drug therapies, identify the 20,000- 30,000 genes…

It was a publicly funded effort of global cooperation betweencompanies, universities, and nations.

From the start a portion of the funds went to ethical research. Why?

Since then many other organisms’ genomes have been sequenced.

genetic engineering

Genes can be transferred from one organism to another, and the gene products produced

even if the organisms are very different,because of the universality of the genetic code.

(Prokaryotes have the same genetic language as do you.)

We will discuss some of what can be done,and what is being pursued.

Whether things should be done is an ethical issue:Is it OK to change the genome of a corn plant?

Of a human?What if it alleviates suffering?

What is the risk of genetically engineering cows? - risk to cows, cows’ neighbors, cows’ consumers? (Science)Is it justified by the possible benefit? (Ethics)

Cloning genestransgenic technology- Subject gene isolated restriction digest, electrophoresis,- amplified PCR,- inserted into plasmid restriction enzymes, DNA ligase, transformation,

and used to either generate the subject gene’s product

(right), or to alter a new host’s genome (left).

(E. coli is most commonhost, but yeasts or other cell types work.)

Recall that prokaryotes don’t have mRNA processing like eukaryotes:

In order to get a useful product, human (e.g.) DNA is transcribed, pre- mRNA is processed, mRNA is isolated,and viral reverse transcriptase is used to make a cDNA (copy DNA), and then a complementary strand is built.(Sticky ends can be added for direct insertion)

NOW it is ready for the snipping, sorting,

and inserting on the previous slide, so the bacterium can generate the protein.

The cloned gene is not of much useuntil you can screen for/select which bacteria have picked up the plasmid.

Gene therapy

Somatic cell line therapy: changes made in the DNA of somatic cells.This can be done in adults,

but has to be redone periodically.

e.g. SCID is the lack of ADA (adenosine deaminase) in white blood cells. - cells are removed from the patient - a virus engineered to carry the ADA gene infects the cells - the gene enters the cell,

allowing for the manufacture of ADA. - The gene is NOT in the

stem cells, so the process is not self propagating.

- These therapies are mostlyexperimental still.

You are given an unidentified DNA sample:What would you do with it?What could you learn from it?

Should all Americans have their DNA on file?Why, and why not?

Pick whichever process you are sketchiest onand do some additional research.

Then help a classmate with it.

Find a recent article about genetic engineering:Which of these processes are mentioned?How many people might be impacted by the results?

Benchmark SC.912.L.16.10

Evaluate the impact of biotechnology on the individual,

society,and the environment,

including medical and ethical issues.

Enduring Understandings

Essential Questions

How is societyinfluenced bybiotechnology?

Biotechnology has the potentialof benefits in agriculture and medicine,but ethical issues linger.

biotechnology forensics

genetic engineering CODIS

electrophoresis PCR

restriction endonuclease transgenic

digests plasmid

DNA fingerprinting DNA ligase

paternity testing reverse transcriptase

DNA profile somatic cell line therapy