1. 12.4 How Is Biotechnology Used In Agriculture?
recombinant
plasmid with Bt gene
Bt genes and plasmids, both with the same complementary sticky ends, are mixed together; DNA ligase bonds the Bt genes into the plasmids.
Fig. 12-9(2)

2. 12.4 How Is Biotechnology Used In Agriculture?
Plasmid-transformed bacteria insert the Bt gene into a plant.
Certain bacteria can enter the cells of specific types of plants.
These bacteria are transformed with the recombinant plasmids.

3. 12.4 How Is Biotechnology Used In Agriculture?
bacterium
bacterial chromosome
recombinant plasmids
Bacteria are transformed with the recombinant plasmids.
Fig. 12-9(3)

4. 12.4 How Is Biotechnology Used In Agriculture?
When the transformed bacteria enter a plant cell, the plasmids insert their DNA, including the Bt gene, into the plant’s chromosomes.

5. 12.4 How Is Biotechnology Used In Agriculture?
plant chromosome
plant cell
Bt gene
Transgenic bacteria enter the plant cells, and Bt genes are inserted into the chromosomes of the plant cells.
Fig. 12-9(4)

6. 12.4 How Is Biotechnology Used In Agriculture?
Therefore, any time that a plant cell divides, all of its daughter cells inherit the Bt gene.
Hormones stimulate the transgenic plant cells to divide and differentiate into entire plants.
These plants are bred to one another, or to other plants, to create commercially valuable plants that resist insect attack.

7. 12.4 How Is Biotechnology Used In Agriculture?
Bt plants resist insect attack.
Fig

8. 12.4 How Is Biotechnology Used In Agriculture?
Genetically modified plants may produce medicines.
Similar techniques can be used to insert medically useful genes into plants, producing medicines.
Plants could be made to produce human antibodies that would combat various diseases.

9. 12.4 How Is Biotechnology Used In Agriculture?
Genetically modified plants may produce medicines (continued).
A direct injection of plant-produced antibodies soon after infection might cure the resulting disease much more rapidly than waiting for the immune system to handle the pathogens.
Plant-derived antibodies against bacteria that cause tooth decay and non-Hodgkins lymphoma could be produced cheaply, enhancing the availability of therapies.

10. 12.4 How Is Biotechnology Used In Agriculture?
Genetically modified animals may be useful in agriculture and medicine.
Making transgenic animals involves injecting the desired DNA into a fertilized egg, which is then implanted into a surrogate mother.
If the offspring are healthy and express the foreign gene, they are then bred together to produce homozygous transgenic organisms.
Companies have developed salmon and trout with modified or added growth-hormone genes, which make the fish grow much faster than wild fish.

11. 12.4 How Is Biotechnology Used In Agriculture?
Genetically modified animals may be useful in agriculture and medicine (continued).
Because medicines are generally more valuable than meat, many researchers are developing animals that will produce medicines.
Alpha-1-antitrypsin: a protein that may prove value in treating cystic fibrosis
Erythropoietin: a hormone that stimulates red blood cell production
Clotting factors for treating hemophilia

12. 12.5 How Is Biotechnology Used To Learn About The Human Genome?
In 1990, the Human Genome Project was launched to determine the nucleotide sequence of all DNA in our entire set of genes, called the human genome.
The human genome contains only about 21,000 genes comprising only 2% of the DNA.
It is not known what the 98% of the remaining DNA does.

13. 12.5 How Is Biotechnology Used To Learn About The Human Genome?
Knowing the human genome will help:
Find out what many unknown proteins do.
Understand human disease.
Diagnose genetic disorders and devise treatments or cures.
Comparing the human genome to that of other organisms will help us understand our place in the evolution of life.

14. 12.6 How Is Biotechnology Used For Medical Diagnosis And Treatment?
DNA technology can be used to diagnose inherited disorders.
People inherit a genetic disease because they inherit one or more dysfunctional alleles.
Defective alleles have different nucleotide sequences than functional alleles.
Two methods are currently used to find out if a person carries a normal allele or a malfunctioning allele.

15. 12.6 How Is Biotechnology Used For Medical Diagnosis And Treatment?
Restriction enzymes may cut different alleles at different locations.
A defective allele may be cut by a particular restriction enzyme, while a functional allele will not.

16. 12.6 How Is Biotechnology Used For Medical Diagnosis And Treatment?
Diagnosing sickle-cell anemia with restriction enzymes
MstII cut #1
MstII cut #2
MstII cut #3
DNA probe
large piece of DNA
small piece of DNA
(a) MstII cuts the normal globin allele into two pieces that can be labeled by a probe
Fig a

17. 12.6 How Is Biotechnology Used For Medical Diagnosis And Treatment?
Diagnosing sickle-cell anemia with restriction enzymes (continued)
MstII cut #1
MstII cut #3
DNA probe
very large piece of DNA
(b)MstII cuts the sickle-cell allele into one very large piece that can be labeled by the same probe
Fig b

18. 12.6 How Is Biotechnology Used For Medical Diagnosis And Treatment?
Diagnosing sickle-cell anemia with restriction enzymes (continued)
larger pieces of DNA
Homozygous sickle-cell: one band of very large DNA
pieces
smaller pieces of DNA
Homozygous normal: one band of large DNA pieces and one band of small DNA pieces
Heterozygous: three bands
(c) Analysis of globin alleles by gel electrophoresis
Fig c

19. 12.6 How Is Biotechnology Used For Medical Diagnosis And Treatment?
Different alleles bind to different DNA probes.
This method has been applied to characterizing the 1,000 different CFTR (cystic fibrosis) protein alleles.

20. 12.6 How Is Biotechnology Used For Medical Diagnosis And Treatment?
A cystic fibrosis diagnostic array
DNA probe for normal CFTR allele
DNA probes for 10 different mutant CFTR alleles
(a) Linear array of probes for cystic fibrosis
colored molecule
piece of patient’s DNA A T C A T C T T T G G T G
(b) CFTR allele labeled with a colored molecule
Fig a,b

21. 12.6 How Is Biotechnology Used For Medical Diagnosis And Treatment?#1
Homozygous for normal CFTR alleles— the person is phenotypically normal #2
One normal and one defective CFTR allele— the person is phenotypically normal #3
Two different defective CFTR alleles— the person develops cystic fibrosis
(c) Linear arrays with labeled DNA samples from three different people
Fig c

22. 12.6 How Is Biotechnology Used For Medical Diagnosis And Treatment?
Someday, physicians may be able to use an array containing hundreds or thousands of DNA probes for hundreds of disease-related alleles.
This will help them determine the susceptibility for the diseases that each patient has, and to tailor the patient’s medical care accordingly.

23. 12.6 How Is Biotechnology Used For Medical Diagnosis And Treatment?
Arrays containing probes for thousands of human genes are already manufactured.
These arrays can be tailored to investigate gene activity in specific diseases, such as breast cancer.

24. 12.6 How Is Biotechnology Used For Medical Diagnosis And Treatment?
A human DNA microarray
Fig

25. 12.6 How Is Biotechnology Used For Medical Diagnosis And Treatment?
DNA technology can be used to treat disease.
Thanks to recombinant DNA technology, several medically important proteins are now routinely made in bacteria.
These proteins may prevent or cure a variety of diseases, but they cannot cure inherited disorders—they only treat symptoms.

26. 12.6 How Is Biotechnology Used For Medical Diagnosis And Treatment?
Biotechnology may be able to treat inherited disorders in the future.
Patients with defective CFTR proteins in their lung cells can have viruses containing normal CFTR alleles sprayed into their nose.
The viruses enter the lung cells, and the normal CFTR allele directs the synthesis of normal CFTR protein.

27. 12.6 How Is Biotechnology Used For Medical Diagnosis And Treatment?
Using biotechnology to cure severe combined immune deficiency (SCID)
In the body, new cells are produced from stem cells that can differentiate into several possible cell types.
SCID is a rare, inherited disorder in which a child fails to develop an immune system; most die before their first birthday.
This disorder is due to a defective allele that does not produce an enzyme called adenosine deaminase.

28. 12.6 How Is Biotechnology Used For Medical Diagnosis And Treatment?
Using biotechnology to cure severe combined immune deficiency (SCID) (continued)
A 4-year old patient had her white blood cells treated with a virus containing a functional allele, and these cells were returned to her body.
Now an adult, she has a normally functioning immune system but must receive continual injections of new treated white cells, since the original treated white cells have died off.

29. 12.7 What Are Some Of The Major Ethical Issues Of Modern Biotechnology?
Should genetically modified organisms (GMOs) be permitted in agriculture?
Even though transgenic crops offer clear advantages to farmers, many people strenuously object to transgenic crops or livestock.
They fear that they may be hazardous to human health or dangerous to the environment.

30. 12.7 What Are Some Of The Major Ethical Issues Of Modern Biotechnology?
Should genetically modified organisms (GMOs) be permitted in agriculture? (continued)
In most cases, there is no reason to think that GMO foods are dangerous to eat.
The Bt protein is not toxic to mammals, and should not prove a danger to human health.
However, some people might be allergic to genetically modified plants.

31. 12.7 What Are Some Of The Major Ethical Issues Of Modern Biotechnology?
Should genetically modified organisms (GMOs) be permitted in agriculture? (continued)
A plant made transgenic by the incorporation of a new gene may confer upon the crop a trait that induces allergic reactions in some people.
In 2003, the U.S. Society of Toxicology studied the risks of genetically modified plants and concluded that the current transgenic plants pose no dangers to human health.

32. 12.7 What Are Some Of The Major Ethical Issues Of Modern Biotechnology?
Are GMOs hazardous to the environment?
Bt genes used in rice fields to add herbicide resistance to the rice may escape in the pollen and enter plants far away from the rice it was intended to control.
The plants receiving the unintentional genes may then also obtain herbicide resistance.

33. 12.7 What Are Some Of The Major Ethical Issues Of Modern Biotechnology?
Are GMOs hazardous to the environment? (continued)
If these plants are weeds, they will become resistant to control by the herbicides and will negatively affect the rice crops.
In 2002, a committee of the U.S. National Academy of Sciences recommended more thorough screening of transgenic plants before they are used commercially, and sustained ecological monitoring after commercialization.

34. 12.7 What Are Some Of The Major Ethical Issues Of Modern Biotechnology?
What about transgenic animals?
Some transgenic animals, such as fish, have the potential to pose significant threats to the environment.
If they escaped, they might be more aggressive, grow faster, or mature faster than wild fish, and might replace native populations.
Commercial fish farms market only sterile transgenic salmon and trout so that escapees would die without reproducing, and thus have minimal effect on the environment.

35. 12.7 What Are Some Of The Major Ethical Issues Of Modern Biotechnology?
Should the genome of humans be changed by biotechnology?
Should people be allowed to select, or even change, the genomes of their offspring?

36. parents with genetic disease
fertilized egg with a defective gene
embryo with a genetic defect
baby with a genetic disorder
therapeutic gene
treated culture
viral vector
Fig

37. genetically corrected cell from culture
egg cell without a nucleus
genetically corrected egg cell
genetically corrected clone of the original embryo
therapeutic gene
healthy baby
Fig

38. 12.7 What Are Some Of The Major Ethical Issues Of Modern Biotechnology?
If it were possible to insert alleles encoding functional CFTR proteins into human eggs, thereby preventing cystic fibrosis, would this be an ethical change to the human genome?
What about making a bigger and stronger football player?
When the technology is developed to cure diseases, it will be difficult to prevent it from being used for nonmedical purposes.