Ch. 13 Outline – Genetic Engineering 2/23/2019

2/23/2019 I. Selective Breeding A. Method of breeding that allows only those individual organisms with desired characteristics to produce the next generation. 1. Examples: a. How humans helped to create all of the different breeds of dogs, cats & other domesticated animals as well as plants. b. Humans “select” who will breed based on the characteristics they want to produce in the offspring. 2/23/2019

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B. Luther Burbank & Plant Hybridization 2/23/2019 B. Luther Burbank & Plant Hybridization 1. He used hybridization to produce new types of plants a. Crossed dissimilar individuals to bring together the best traits of both b. Hybrids are often hardier than either parent c. Most of our food crops are hybrids today 2/23/2019

Hybrid corn in center: parents on sides 2/23/2019

1. Continued breeding of individuals with similar characteristics. 2/23/2019 C. Inbreeding 1. Continued breeding of individuals with similar characteristics. a. Can help maintain each breed’s unique traits 2. Risks: a. Two very similar organisms may share recessive alleles for a genetic defect b. Examples: Joint deformities in German shepherds & golden retrievers 2/23/2019

Genetic Deformities 2/23/2019

2/23/2019 D. Increasing Variation 1. Breed plants or animals with slightly different varieties found in nature 2. Induce mutations: a. Can increase natural mutation rate by using: •Radiation •Chemicals b. Most will be harmful but a few might create desirable traits c. Polyploidy in plants can be induced using drugs that prevent chromosome separation during meiosis 2/23/2019

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II. Genetic Engineering 2/23/2019 II. Genetic Engineering A. The process of manipulating genes for practical purposes. 1. Example: a. Get bacteria to build human insulin for diabetics B. Recombinant DNA 1. DNA made from 2 or more different organisms 2. Example: a. Put gene for human insulin into bacteria 2/23/2019

C. Steps of Genetic Engineering of Human Insulin: 2/23/2019 C. Steps of Genetic Engineering of Human Insulin: 1. Cutting DNA a. Need to cut DNA from organism of interest (human) b. Need to cut DNA from a vector  This is an agent that is used to carry the gene of interest into another cell  Common vectors are viruses, yeast and plasmids  Plasmids are separate circular DNA molecules found in bacteria 2/23/2019

c. The DNA from both organisms is cut with restriction enzymes 2/23/2019 c. The DNA from both organisms is cut with restriction enzymes  These are bacterial enzymes that recognize specific short sequences of DNA & then cut them  Example: CGCGCGCGATATAT GCGCGCGCTATATA CGCG & CGCGATATAT GCGCGCGCTA TATA Leaves unpaired bases “sticky ends” 2/23/2019

2. Making recombinant DNA 2/23/2019 2. Making recombinant DNA a. DNA fragments from organism & vector are combined  Sticky ends will base pair & join fragments together human CGCGCGCGATATAT GCGCGCGCTATATA vector b. Enzyme, DNA ligase, is added to bond the DNA fragments together 2/23/2019

2/23/2019 c. Bacterial host cells are then treated to allow them to “take up” or absorb the new DNA plasmid d. Host bacteria now have a plasmid with insulin gene in it. The bacteria have been “transformed” Insulin gene Host bacterium 2/23/2019

2/23/2019 3. End Results a. Bacterial cells containing the gene for human insulin can be allowed to reproduce b. Each time the bacteria reproduce they are making copies of the gene of interest. This is called gene cloning. c. The bacteria can then produce vast quantities of insulin for medical uses. 2/23/2019

III. Making Copies of DNA 2/23/2019 III. Making Copies of DNA A. To study DNA biologists often need many copies of a particular gene. 1. Polymerase Chain Reaction (PCR) a. A technique to quickly produce many identical pieces of DNA in the lab b. DNA is basically heated up until the two sides separate c. Then it is allowed to cool d. In the presence of loose nucleotides & DNA polymerase, the other sides of the DNA molecules are then produced. e. Repeat heating & cooling process until you have lots of copies 2/23/2019

Polymerase Chain Reaction 2/23/2019 PCR Polymerase Chain Reaction

2/23/2019 IV. DNA Fingerprinting A. No two individuals have exactly the same genetic material (except for identical twins) 1. If restriction enzymes are used to cut a person’s DNA into fragments, the resulting pieces will differ between individuals 2. DNA fragments of different lengths are called RFLPS (restriction fragment length polymorphisms) 2/23/2019

a. DNA fragments are placed into pits in a rectangular piece of gel 2/23/2019 B. Treatment of RFLPs: 1. Electrophoresis a. DNA fragments are placed into pits in a rectangular piece of gel b. The gel is placed into an electrical box and the current is turned on  Since DNA is (-) charged, the fragments will move to the (+) pole  Smallest pieces move fastest  Largest pieces move slowest 2/23/2019

Gel Electrophoresis Equipment 2/23/2019

2. A pattern of bands is formed on gel 2/23/2019 2. A pattern of bands is formed on gel a. The resultant picture of the bands is called a DNA fingerprint  Every person has a unique DNA fingerprint 2/23/2019

Gel Electrophoresis Results 2/23/2019

Gel Electrophoresis Results 2/23/2019

3. Uses of DNA fingerprints 2/23/2019 3. Uses of DNA fingerprints a. To establish whether people are related (i.e. paternity suits) b. Forensic science  Scientific investigation of criminal activity (cause of injury or death)  Use blood, semen, bone, or hair to identify victims & suspects c. Identifying genetic disorders  Sickle cell anemia, cystic fibrosis, Tay Sachs, etc. 2/23/2019

DNA Fingerprinting in Criminology 2/23/2019

V. Genetic Engineering in Medicine 2/23/2019 V. Genetic Engineering in Medicine A. Hundreds of medically important proteins are now being genetically engineered using bacteria. 1. Examples: a. anticoagulants – prevent blood clots b. Factor VIII – aids in blood clotting. Helps hemophiliacs c. Vaccines – for herpes & hepatitis and others. 2/23/2019

♣ Repair immune disorders 2/23/2019 B. Gene Therapy 1. Technique that involves putting a healthy copy of a gene into cells of a person whose copy is defective. a. Examples: ♣ Repair immune disorders ♣ Nasal sprays to give normal genes to patients with cystic fibrosis 2/23/2019

VI. Genetic Engineering in Agriculture 2/23/2019 VI. Genetic Engineering in Agriculture A. Have changed plants to: 1. make more tolerant to drought 2. make more tolerant to freezing 3. make crops resist insects 4. adapt to different soils 5. fruits ripen more quickly 6. improve nutritional value (added genes for Vitamin A and iron to rice) 2/23/2019

Herbicide Resistant plants 2/23/2019 Herbicide Resistant plants

b. These animals are called transgenic animals. 2/23/2019 B. Modify Animals 1. Added growth hormone to cows to increase milk production 2. Added human genes to farm animals to get them to produce human proteins a. They extract the proteins from the milk and are sold to pharmaceutical companies. b. These animals are called transgenic animals. 2/23/2019

VII. Human Genome Project 2/23/2019 VII. Human Genome Project A. Its goal was to determine the nucleotide sequence of every gene on every human chromosome. B. This has been completed, sort of. The genome has been sequenced but we don’t yet know what every gene is. C. Someday this could lead to cures for some 4,000 genetic defects. 2/23/2019