1. Frontiers of Biotechnology

2. Manipulating DNA
Scientists use several techniques to manipulate DNA

3. Restriction Enzymes cut DNA
Why cut DNA?
To study specific genes instead of ALL the genes on a chromosome
Restriction enzymes act as molecular scissors
Recognize specific sequences
Some leave “blunt ends”
Some leave “sticky ends”

4. Restriction Maps show the lengths of DNA fragments
Gel Electrophoresis: a technique that uses an electrical field within a gel to separate molecules by their size
DNA is negatively charged and moves toward the positive pole when the electrical field is applied
Smallest DNA fragments move the fastest
A pattern of bands is formed

5. Gel Electrophoresis

6. Polymerase Chain reaction
PCR: technique that produces millions of copies of a specific DNA sequence in just a few hours
Invented by Kary Mullis in 1983

7. PCR Uses: 3 Step Process: DNA to be copied DNA polymerase
Plenty of nucleotides A, T, C, and G
Two primers
3 Step Process:
Separating
Binding
Copying

8. RFLPs Restriction Fragment Length Polymorphisms
No two individuals have the same genetic material except identical twins
Restriction enzymes cut at different places, depending on the DNA sequence
The lengths of DNA restriction fragments are different between two individuals

9. DNA fingerprinting A DNA fingerprint is a type of restriction map
Representation of parts of a individual’s DNA that can be used to identify a person at the molecular level
Focuses on noncoding regions of DNA, or DNA sequences outside genes

10. DNA Fingerprinting DNA sample from: …Useful in forensics! Blood Semen
Bone
Hair
…Useful in forensics!

11. DNA fingerprinting is used for identification
DNA fingerprints and probability
Compare at least 5 regions of the genome

12. Genetic Engineering Entire organisms can be cloned
Clone: genetically identical copy of a gene or of an organism
New genes can be added to an organism’s DNA

13. 4 Basic Steps to Genetic Engineering
1. Cutting DNA
2. Making recombinant DNA
3. Cloning
4. Screening

14. Step 1: Cutting DNA
The DNA from the original organism containing the gene of interest is cut by restriction enzymes
Restriction Enzymes: bacterial enzymes that destroys foreign DNA molecules by cutting them at specific sites

15. Step 1: Cutting DNA
Vector: Any agent, such as a plasmid, that carries the gene of interest into another cell
Plasmid: A circular DNA molecule that is usually found in bacteria and that can replicate independent of the main chromosome

16. Recombinant DNA DNA molecules that are artificially created HOW?????
Created by combining DNA from different sources

17. Example: Insulin A protein hormone that controls sugar metabolism
Diabetics cannot produce enough
Must take doses of insulin daily
Before genetic engineering, insulin was extracted from the pancreases of slaughtered cows and pigs and then purified
Today the human insulin gene is transferred to bacteria through genetic engineering
Because the genetic code is universal, bacteria can transcribe and translate the human insulin gene

18. Step 2: Making Recombinant DNA
DNA fragments from the gene of interest are combined with the DNA fragments from the vector
DNA ligase: an enzyme that bonds the DNA fragments together
The host cell then takes up the recombinant DNA

19. Step 3: Cloning
Gene Cloning: many copies of the gene of interest are made each time the host cell reproduces
Remember: bacteria reproduce by binary fission, producing identical offspring with the plasmid DNA!

20. Step 4: Screening
Cells that have received the particular gene are separated from the cells that did not take up the vector with the gene of interest
The cells can transcribe and translate the gene of interest to make the protein coded for the gene

21. Confirmation of a Cloned Gene
Southern Blot: a technique used to test for the presence of a specific gene

22. Northern Blot
Similar to a Southern Blot
Uses RNA instead of DNA

23. Genetic Engineering produces organisms with new traits

24. Selective Breeding
Allowing only those animals with desired characteristics to produce the next generation
Horses, cats, farm animals, crops

25. Hybridization
Crossing dissimilar individuals to bring together the best of both organisms
Hybrids: the individuals produced from such crosses
For example, a disease resistant plant and the food producing capacity of another

26. Inbreeding
The continued breeding of individuals with similar characteristics
Often seen in dogs
Retains characteristics but has risks
Genetically similar individuals could bring together two recessive alleles for a genetic defect

27. Today… Genetic Engineering

28. Genetically Engineered Crops
More tolerant to drought
Plants that can adapt to different soils, climates, and environmental stresses

29. Genetically Engineered Crops
Resistant to biodegradable weedkiller Glyphosate (kills weeds but now doesn’t kill the crop)
Resistant to insects (gene injures the gut of chewing insects)-therefore plant doesn’t need to be sprayed with pesticides

30. More Nutritious Crops Improve the nutritious value of many crops
Asia: rice is a staple food
Low in iron an beta carotene
Iron deficient and poor vision
Genetic engineers have added genes to rice from other plants to overcome this deficiency

31. Potential Problems to GM Crops
Concern that some weeds will become resistant to the weed killer Glyphosate
New weed-control alternatives will have to be implemented

32. Potential Problems to GM Crops
Nutritional value has been increased in many crops
Crops must be tested to make sure consumers are not allergic to the GM product

33. Gene Technology: Animal Farming
Farmers added growth hormones to the diet of cows to increase milk production
Growth hormone was extracted from the brains of dead cows
The hormone was introduced into bacteria and added as a supplement to a cow’s diet

34. Transgenic Animals Animals that have foreign DNA in their cells
Human genes have been added to farm animals in order to get the farm animals to produce human proteins in their milk

35. Transgenic Animals
This is complex and cannot be made by bacteria through gene technology
Human proteins are extracted from the animal’s milk and sold for pharmaceutical purposes
Cloning animals: creating herds of identical animals that can make medically useful proteins

36. Cloning from Adult Animals
The intact nucleus of an embryonic or fetal cell (whose DNA has been recombined with a human gene) is placed into an egg whose nucleus has been removed
The egg with the new nucleus is put in the uterus of a surrogate, or substitute mother and allowed to develop

37. Cloning from Adult Animals
1997 Ian Wilmut  first successful cloning using differentiated cells from an adult animal
Dolly the sheep

38. Cloning from Adult Animals
Differentiated cells: cells that have become specialized to become specific cell types
Scientists had thought that embryonic or fetal cells were the only way…wrong!

39. Cloning from Adult Animals
Mammary cells from one sheep were fused with egg cells without nuclei form a different sheep
The fused cells divided to form embryos, implanted into surrogate mothers
Only one survived the cloning process
Dolly, identical to the sheep that provided the mammary cell

41. Problems with Cloning
Only a few of the cloned offspring survive for long
Many become fatally oversized
Problems in development

42. Genomic Imprinting
The right combination of genes are turned “on” and “off” during early development
The egg takes years to develop the genomic imprint
In cloning, the egg divides within minutes

43. Genomic Imprinting Reprogramming is not possible in such a short time
Critical errors in development can occur
Because of these technical problems and ethical problems, cloning humans is illegal in most countries

44. Concerns about genetic engineering
Ethical?
GM crops
Not enough research had been done to see if added genes might cause allergic reactions or have other unknown side effects
Interbreeding with natural plants…what does it mean?

45. Genomics involves the study of genes, gene functions, and entire genomes
Genomics: The study of genomes, which can include the sequencing of all of an organism’s DNA
Gene sequencing: determining the order of DNA nucleotides in genes or in genomes

46. The Geography of the Genome
Only 1-1.5% of the human genome codes for proteins
Each human cell contains about 6 feet of DNA
Less than 1 inch are exons

47. The Geography of the Genome
Human cells contain about 25,000 genes (scientists had expected 120,000!)
Only 2x the number of genes in a fruit fly!
Many human genes are identical to those of other species
All humans are genetically close (DNA of any 2 people is 99.9% identical)

48. The human genome project
Our genome is relatively small! 3 billion base pairs, but only between 30,000-40,000 genes
Project started in 1990 with 2 main goals:
Map and sequence all of the DNA base pairs of the human chromosomes (accomplished in 2003)
Identify all of the genes within the sequence (still be worked on)

49. The human microbiome project
200 scientists at 80 institutions sequenced the genetic material of bacteria taken from nearly 250 healthy people
As many as a thousand bacterial strains on each person.
Each person’s collection of microbes, the “microbiome”, was unique

50. Technology allows the study and comparison of both genes and proteins
Bioinformatics: the use of computer databases to organize and analyze biological data
DNA microarrays: tools that allow scientists to study many genes, and their expression at once; a small chip dotted with the genes being studied
Proteomics: the study and comparison of all the proteins that result from an organism’s genome

51. Genetic screening and gene therapy
Genetic screening: the process of testing DNA to determine a person’s risk of having or passing on a genetic disorder
Gene therapy: the replacement of a defective of missing gene, or the addition of a new gene, into a person’s genome to treat a gene

52. Genetically Engineered Drugs & Vaccines
Possibilities for the applications of genetic engineering are endless!

53. Drugs
Many genetic disorders and other human illnesses occur when the body fails to make critical proteins
Example: juvenile diabetes
Body is unable to control levels of sugar in the blood because the protein insulin cannot be made
Example: Hemophilia
Factor VIII, a protein that promotes blood clotting
Donated blood was sometimes infected with HIV and hepatitis B
Genetically engineered factor VIII eliminates these risks

54. Vaccines Traditional Vaccines Genetically Engineered Vaccines
Many viral diseases, such as smallpox and polio, cannot be treated effectively by existing drugs
Vaccine: a solution containing all or part of a harmless version of a pathogen (disease-causing microorganism)
When the vaccine is injected, the immune system recognizes the pathogen’s surface proteins and responds by making defensive proteins called antibodies
Avoid the danger of giving a patient a disease
The genes that encode the pathogen’s surface proteins can be inserted into the DNA of harmless viruses, such as cowpox
The modified, harmless cowpox virus becomes an effective, safe vaccine