1. Biotechnology and Genetic Engineering - Bio A

2. What is Genetic Engineering?
a set of technologies used to change the genetic makeup of cells
Often we move genes from one species to another
produce novel organisms
Create factories to make chemical compounds

3. Before Genetic Engineering:
Selective Breeding
Non-random mating to select for characteristics in parents that are desired in the offspring
Examples: Domestic animals, domestic crops

4. Examples: Dogs
Did you know that as they domesticated the wolf, spots were an indication of docility (easier to handle)

5. Example: Udders (more milk)
Cows must be milked every day due to their large udders!

6. Amount of muscle (meat)
Angus Bull

7. Sheep: More wool
Sheep must be “shorn” in spring to prevent problems with heat stroke!

8. Corn: More to eat per ear
Stalks of corn can hold 3-4 ears per stalk!...it used to look more like “wheat” (see picture)

9. Benefits
Economic:
More from each animal  less cost, less space needed to make the same profit

10. Issues
Future generations - very similar genes. Decreased variability ->
Increased risk of disease wiping out all
Loss of gene variation  hard to produce new varieties
SO…‘inbreeding can lead to a reduction in the size of the gene pool’ (less variation).

11. Genetic Engineering
Instead of breeding to hopefully get a trait, we identify the gene and TRANSFER IT!

12. Genetic Engineering
Direct manipulation of genes to alter hereditary traits.
Advances in technology have enabled scientists to use several different techniques to study and alter DNA sequences.

13. Use genetic engineering to:
Make transgenic organisms
Clone
Provide gene therapy

14. Transgenic Organisms
Organisms which express a gene from another organism
How: We cut a gene out of one organism and INSERT the gene into another organism into another
EXAMPLE: human insulin gene put into bacteria

15. How is this done?
Use special enzymes (restriction enzymes) to cut the bacterial DNA at very specific locations
Result: Sticky ends
For example: G A A T T C
C T T A A G
We do this in the bacteria, and in the gene

16. Recombinant DNA
Scientists can use sticky ends to join together segments of DNA from two different organisms, which is called recombinant DNA.
Foreign DNA is put into a plasmid, a circular piece of DNA found in bacteria.

18. plasmid
Enzymes cut plasmid and foreign DNA
The desired DNA segment is inserted into the plasmid.
Foreign DNA
Plasmid with foreign DNA

19. Transgenic organisms
The plasmid with the new DNA can be inserted into a new organism.
This is creates a transgenic organism

20. Genetic Engineering -Human DNA and Bacteria

21. Agricultural uses: genetically modified organisms (GMO)
To give crops disease/ drought resistance, add nutrients, etc
Flavr Savr tomato: modified to ripen slower
Golden rice: rice with added genes to make Vitamin A

22. Genetically engineered organisms
Plants resistant to herbicide
What is the advantage?

23. Extra copies of growth hormone

24. Fun things that glow in the dark

25. Medical uses: Gene therapy
Genetic diseases are often caused by genes that do not function properly.
Gene therapy tries to fix a problem. Scientists use a virus to insert a functioning gene into the patient.
Example: Cystic Fibrosis- missing one gene.
We have succeeded with dogs,but not people!

26. Summary - Recombinant DNA
Recombinant DNA (rDNA) is DNA that has been created artificially.
It involves DNA from two or more sources being incorporated into a single “recombinant” molecule.
could be the same species (like cystic fibrosis)
or different species (like the bacteria and the insulin gene

27. Reasons? Better Crops (drought & insect resistance)
Larger livestock (cows, chickens, hogs)
Recombinant Vaccines (ie. Hepatitis B)
Prevention and cure of genetic diseases like CF
Production of insulin
Plants that produce their own insecticides

28. How does Cloning work?
Unlike sexual reproduction where mammals usually fuse chromosome info from two parents
Cloning takes all the chromosomes from 1 animal and (but still involves 2 cells)
SO…HOW DOES THIS WORK???

29. How do we clone? We use 2 cells from two different animals
Sheep 1
Take 1 body cell (udder)
Extract Nucleus
Sheep 2
Take 1 egg cell
Remove nucleus

30. Cloning Requires 2 cells from two DIFFERENT animals
Remove the nucleus from an egg cell of one female.
Replace with a nucleus from the individual to be cloned.
When you have a 2N nucleus in an egg it acts as if it is fertilized.
The cell will begin to divide and form an embryo.

31. HOW DO WE CLONE? Zap to stimulate cell division
Implant embryo into surrogate sheep (sheep 3)
Inject nucleus into Egg

32. NOW WE WAIT FOR DOLLY…. Which sheep is Dolly identical to?? Why?
Which sheep have to be female?

34. Dolly- first cloned mammal

35. Cloning Dolly (summary)
Somatic cell (2N chromosomes) was used from one animal (this is who we are cloning).
We extract and keep the nucleus (get rid of the rest)
Egg cell from a second animal (nucleus contains only 1N chromosomes)
Extract and get rid of nucleus and keep the cell
Fuse the two together  zygote  put into a 3rd sheep to gestate.

36. Original, Clone and surrogate
Snuppy surrogate

37. Why DO WE CLONE?
Two mini clone pigs, nine days after they were born. Their internal organs are quite similar with those of human beings and are used for organ transplant experiments.
Scientific experimentation
Maintain a genetic line (good sire or dam)

38. Cloning Implant embryo into a surrogate mother.
The offspring that is born will be a genetic clone (not related to surrogate mother).

39. Dolly was the first animal to be successfully cloned
Dolly was the first animal to be successfully cloned. She was cloned by Ian Wilmut, Keith Campbell and colleagues at the Roslin Institute in Edinburgh, Scotland.
Born July 5, 1996
Died Feb 14, 2003

40. Gel Electrophoresis
Method used to separate DNA fragments based on their charge and size.
Why do this?
Fragments of DNA can be used
in gene technology (the insulin gene or the CFTR gene), or
to identify individuals (DNA fingerprint)

41. Steps in Electrophoresis
Create an agarose gel with wells at the top of each lane.
Add DNA samples into each well.
Electric current pulls DNA towards positive end of the gel.

43. Gel electrophoresis cont.
DNA segments separate by size.
The longer segments move slower so they stay at the top and the shorter segments move faster and are at the bottom.

44. Gel electrophoresis cont.
A “ladder” is also added in another lane.
It is made of DNA fragments of known sizes.
It acts like a ruler to measure the unknown fragment lengths.

45. DNA Fingerprinting Use enzymes to cut DNA samples into segments.
A technique used to compare or identify similarities between samples of DNA.
Use enzymes to cut DNA samples into segments.
Everyone has different length segments because of random repeated sequences.

46. Use gel electrophoresis to separate different lengths of DNA.
Compare the pattern of the DNA bands .
Matching lengths will appear at the same distance.

48. Example: While DNA in all humans is similar there are differences
within families that can be used to identify a child’s parents.
In this example (next page) , a family consists of a mom and dad, two daughters and two sons. The parents have one daughter and one son together, one daughter is from the mother’s previous marriage, and one son is adopted, sharing no genetic material with either parent. After amplifying the VNTR DNA from each member of the family, it is cut with a restriction enzyme and run on an agarose gel. Here are the results:

49. Example of DNA fingerprint
Which child is adopted? Will any child look exactly like Mom or Dad? One child is a “step child to one of the adults, but the actual child of the other…can you tell who?

50. Example 2. Who did it? What is a ladder? Where are the suspects?
Where is the boyfriend
Who committed the rape?
How do you know?

51. So ..what exactly do we know about us?

52. Human Genome Project
What it did do: Tell us each an every nucleotide of the human genome (all 3.2 billion)
What it did not do: Tell us what it all means!!!

53. Human Genome Project…where are we?
Now we have to break it down and determine:
- which pieces are genes
- which pieces are junk
- what info the genes hold.

54. Where do we store all the information we learn since the whole world is working on this project?
New major: Bioinformatics

55. Bioinformatics
The application of computer science to the field of molecular biology.
Bioinformatics now includes the creation and advancement of databases, algorithms, computational and statistical techniques, and theory to solve formal and practical problems arising from the management and analysis of biological data.
How do we “search” for a gene?

56. BLAST sequence
BLAST finds regions of similarity between biological sequences.
Use a sequence of nucleotides (nucleotide BLAST) or amino acids (protein BLAST)
For example, following the discovery of a previously unknown gene in the mouse, a scientist will typically perform a BLAST search of the human genome to see if humans carry a similar gene
Similar gene-> similar function? And we now have a model system to experiment with (that is not human)

57. So …where do we use Gene Technology?
Agriculture
Medicine
Basic research

58. Ethics of Gene Technology
Are we blurring the lines between species by creating transgenic combinations?
What are the known health risks associated with transgenics?
What are the long-term effects on the environment when transgenics are released in the field?
Are we inflicting pain and suffering on animals when we create certain types of chimeras (multiple species animals)?
Will transgenic interventions in humans create physical or behavioral traits that may or may not be readily distinguished from what is usually perceived to be “human”?
WE ARE STILL LEARNING….