1. Concept 13.4 Biotechnology Has Wide Applications
Many medically useful products are being made using biotechnology.
Insulin was the first to be made by recombinant DNA technology in E. coli.

2. Figure 13.12 Human Insulin: From Gene to Drug
Figure Human Insulin: From Gene to Drug Human insulin chains are made by recombinant DNA technology and then combined to produce the widely used drug.
The two insulin polypeptides were synthesized separately using a vector with the lacZ (β-galactosidase) gene.
The insulin genes were transcribed and translated along with the lacZ genes.
After synthesis, the polypeptides were cleaved and the two insulin peptides were combined to make a functional human insulin molecule.

3. Concept 13.4 Biotechnology Has Wide Applications
Before giving it to humans, scientists had to be sure of its effectiveness:
Same size as human insulin
Same amino acid sequence
Same shape
Binds to the insulin receptor on cells and stimulates glucose uptake

4. Concept 13.4 Biotechnology Has Wide Applications
Pharming: production of pharmaceuticals in farm animals or plants
Example: Transgenes are inserted next to the promoter for lactoglobulin, a protein in milk. The transgenic animal then produces large quantities of the protein in its milk.

5. The transgenic offspring produce the new protein in their milk.
Figure Pharming
An expression vector carrying a desired gene can be put into an animal egg, which is implanted into a surrogate mother.
Figure Pharming An expression vector carrying a desired gene can be put into an animal egg, which is implanted into a surrogate mother. The transgenic offspring produce the new protein in their milk. The milk is easily harvested and the protein isolated, purified, and made clinically available for patients.
The milk is easily harvested and the protein isolated, purified, and made clinically available for patients.
The transgenic offspring produce the new protein in their milk.

6. Concept 13.4 Biotechnology Has Wide Applications
Human growth hormone (hGH) can now be produced by transgenic cows.
With only 15 such cows, we could supply hGH for all the children in the world that suffer from pituitary dwarfism.
An enzyme to treat Gaucher’s disease (inherited disorder that affects lipid breakdown in lysosomes) has been developed using transgenic carrot cells.

7. Cloning Plants: Single-Cell Cultures
One experimental approach for testing genomic equivalence is to see whether a differentiated cell can generate a whole organism
A totipotent cell is one that can generate a complete new organism
Plant cloning is used extensively in agriculture
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8. Cross section of carrot root
Figure 20.17
Cross section of carrot root
2-mg fragments
Fragments were cultured in
nutrient medium; stirring caused single cells to shear off into the liquid.
Single cells free in suspension began to divide.
Embryonic plant developed from a cultured single cell.
Plantlet was cultured on agar medium. Later it was planted in soil.
Adult plant
Figure The cloning of a whole carrot plant from a single carrot cell.

9. Cloning Animals: Nuclear Transplantation
In nuclear transplantation, the nucleus of an unfertilized egg cell or zygote is replaced with the nucleus of a differentiated cell
Experiments with frog embryos have shown that a transplanted nucleus can often support normal development of the egg
However, the older the donor nucleus, the lower the percentage of normally developing tadpoles
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10. Egg with donor nucleus activated to begin development
Figure 20.18
EXPERIMENT
Frog embryo
Frog egg cell
Frog tadpole UV
Fully differ- entiated (intestinal) cell
Less differ- entiated cell
Donor nucleus trans- planted
Donor nucleus trans- planted
Enucleated egg cell
Egg with donor nucleus activated to begin development
RESULTS
Figure Inquiry: Can the nucleus from a differentiated animal cell direct development of an organism?
Most develop into tadpoles.
Most stop developing before tadpole stage.

11. Reproductive Cloning of Mammals
In 1997, Scottish researchers announced the birth of Dolly, a lamb cloned from an adult sheep by nuclear transplantation from a differentiated mammary cell
Dolly’s premature death in 2003, as well as her arthritis, led to speculation that her cells were not as healthy as those of a normal sheep, possibly reflecting incomplete reprogramming of the original transplanted nucleus
© 2011 Pearson Education, Inc.

12. Cultured mammary cells
Figure 20.19
TECHNIQUE
Mammary cell donor
Egg cell donor 1 2
Egg cell from ovary
Nucleus removed 3
Cells fused
Cultured mammary cells
Nucleus from mammary cell 4
Grown in culture
Early embryo 5
Implanted in uterus of a third sheep
Figure Research Method: Reproductive Cloning of a Mammal by Nuclear Transplantation
Surrogate mother 6
Embryonic development
RESULTS
Lamb (“Dolly”) genetically identical to mammary cell donor

13. Cultured mammary cells
Figure 20.19a
TECHNIQUE
Mammary cell donor
Egg cell donor 1 2
Egg cell from ovary
Nucleus removed 3
Cells fused
Cultured mammary cells
Figure Research Method: Reproductive Cloning of a Mammal by Nuclear Transplantation
Nucleus from mammary cell

14. Nucleus from mammary cell
Figure 20.19b
Nucleus from mammary cell 4
Grown in culture
Early embryo 5
Implanted in uterus of a third sheep
Surrogate mother
Figure Research Method: Reproductive Cloning of a Mammal by Nuclear Transplantation 6
Embryonic development
RESULTS
Lamb (“Dolly”) genetically identical to mammary cell donor

15. Cloned animals do not always look or behave exactly the same
Since 1997, cloning has been demonstrated in many mammals, including mice, cats, cows, horses, mules, pigs, and dogs
CC (for Carbon Copy) was the first cat cloned; however, CC differed somewhat from her female “parent”
Cloned animals do not always look or behave exactly the same
© 2011 Pearson Education, Inc.

16. Figure 20.20
Figure CC, the first cloned cat, and her single parent.

17. Problems Associated with Animal Cloning
In most nuclear transplantation studies, only a small percentage of cloned embryos have developed normally to birth, and many cloned animals exhibit defects
Many epigenetic changes, such as acetylation of histones or methylation of DNA, must be reversed in the nucleus from a donor animal in order for genes to be expressed or repressed appropriately for early stages of development
© 2011 Pearson Education, Inc.

18. Concept 13.4 Biotechnology Has Wide Applications
Recombinant DNA technology has several advantages:
Specific genes can be targeted
Any gene from any organism can be introduced into any other organism
New organisms can be generated quickly
Recombinant DNA technology has many applications in agriculture.

19. Figure 13.14 Genetic Modification of Plants versus Conventional Plant Breeding
Figure Genetic Modification of Plants versus Conventional Plant Breeding Plant biotechnology offers many potential advantages over conventional breeding. In the hypo-thetical example here, the objective is to transfer gene(s) for short, strong stems into a wheat plant that has high grain production but a tall, weak stem.

20. Table 13.2

21. Concept 13.4 Biotechnology Has Wide Applications
Crop plants that make their own insecticides:
The bacterium Bacillus thuringiensis produces a protein (Bt) that kills insect larvae.

22. Concept 13.4 Biotechnology Has Wide Applications
Bt is highly toxic but breaks down rapidly in the environment.
Genes for the toxin have been isolated, cloned, modified, and inserted into plant cells using the Ti plasmid vector.
Transgenic corn, cotton, soybeans, tomatoes, and other crops are being grown, and pesticide use is reduced.

23. Figure 13.15 Transgenic Rice Rich in β-Carotene
Crops with improved nutritional characteristics:
Golden rice contains genes from daffodils or corn and a bacterium, for enzymes involved in β-carotene production. (Vitamin A precursor)
Figure Transgenic Rice Rich in -Carotene Right and middle: The grains from these transgenic rice strains are colored because they make the pigment -carotene, which is converted to vitamin A in the human body. Left: Wild-type rice grains do not contain -carotene.

24. Figure 13.16 Salt-tolerant Tomato Plants
Crops that are tolerant of environmental conditions:
Example: Plants that are salt-tolerant
Figure Salt-tolerant Tomato Plants Transgenic plants containing a gene for salt tolerance thrive in salty water (A), whereas plants without the transgene die (B). This technology may allow crops to be grown on salty soils.

25. Concept 13.4 Biotechnology Has Wide Applications
Concerns about genetically modified crops center on these claims:
1. Genetic manipulation is an unnatural interference in nature.
2. Genetically altered foods are unsafe to eat.
3. Genetically altered crop plants are dangerous to the environment.

26. Concept 13.4 Biotechnology Has Wide Applications
1. Advocates of biotechnology point out that all crop plants have been manipulated by humans.
2. Since only single genes for plant function are inserted into crop plants, advocates contend they are safe for human consumption.
Genes that affect human nutrition may raise more concerns.

27. Concept 13.4 Biotechnology Has Wide Applications
3. Concern over environmental effects centers on escape of transgenes into wild populations.
Example: If a gene for herbicide resistance were transferred to a closely related weed

28. Concept 13.4 Biotechnology Has Wide Applications
Widespread use of glyphosate on glyphosate- resistant crops has resulted in selection of rare mutations in weeds that make them resistant to glyphosate.
More than 10 resistant weed species have appeared in the United States.