Chapter 9: Biotechnology 9.1, 9.3, & 9.4

9.1: Manipulating DNA Key Concept: Biotechnology relies on cutting DNA at specific places.

Scientists use several techniques to manipulate DNA. Chemicals, computers, and bacteria are used to work with DNA. Scientists use these tools in genetics research and biotechnology.

Restriction enzymes Collected from bacteria Used for cutting DNA to isolate specific gene or genes Cut DNA at specific nucleotide sequences called restriction sites. Can leave blunt ends (straight cuts) or sticky ends (staggered cuts with free nucleotides) Cut DNA can be used to study gene sequence or placed into the DNA of another organism.

Restriction sites

Restriction maps show the lengths of DNA fragments. Gel electrophoresis is used to separate DNA fragments by size. A DNA sample is cut into fragments with restriction enzymes. Electrical current pulls DNA fragments through a gel. Smaller fragments move faster and travel farther than larger fragments. Fragments of different sizes appear as bands on the gel

A restriction map shows the lengths of DNA fragments between restriction sites. Only indicate size, not DNA sequence Useful in genetic engineering, studying mutations (may change lengths of fragments), or for DNA fingerprinting.

Restriction Enzymes https://www.youtube.com/watch?v=lWXryzgRces

9.3: DNA Fingerprinting Key Concept: DNA fingerprints identify people at the molecular level

A DNA fingerprint is a type of restriction map. DNA fingerprints are based on parts of an individual’s DNA that can be used for identification Based on noncoding regions of DNA Noncoding regions have repeating DNA sequences Number of repeats differs between people Banding pattern on a gel is a DNA fingerprint

DNA fingerprinting is used for identification. DNA fingerprinting depends on the probability of a match. Many people have the same number of repeats in a certain region of DNA The probability that two people share identical numbers of repeats in several locations is very small (only one chance in 1 billion-10 billion people that they would match) Several regions of DNA are used to make a DNA fingerprint to make it more likely the fingerprint is unique.

(mother) (child 1) (child 2) (father)

Uses of DNA Fingerprinting Forensics: evidence in criminal cases Paternity tests Immigration requests Positive identification Studying biodiversity Tracking genetically modified crops

http://www.youtube.com/watch?v=PSwlCk_Z02c

9.4: Genetic Engineering Key Concept: DNA sequences of organisms can be changed.

Genetic Engineering Involves changing an organism’s DNA to give it new traits Based on the use of recombinant DNA Recombinant DNA contains DNA from more than one organism Gene splicing involves cutting the gene from one organism and pasting it into another organism’s DNA to give it the trait coded for by that gene (makes recombinant DNA)

Gene Splicing Bacteria frequently used in genetic engineering because they have plasmids – closed loops of DNA. (bacterial DNA)

Genetic engineering produces organisms with new traits. Gene splicing involves cutting the gene from one organism and pasting it into another organism’s DNA to give it the trait coded for by that gene. Restriction enzymes cut plasmid and foreign DNA Foreign gene inserted into plasmid

Uses of Genetic Engineering Medicine: Transgenic bacteria can be used to produce human proteins “pharming” Bacteria can be used to produce human insulin for diabetics Provides a steady, inexpensive supply. Transgenic plants are common in agriculture transgenic bacteria infect a plant plant expresses foreign gene many crops are now genetically modified (GMO) Gives them traits like resistance to frost, diseases, insects Increase crop yield – more food quickly and cheaply Increase nutrient levels in crops like rice. Transgenic animals are used to study diseases and gene functions

Concerns about Genetic Engineering Possible long-term health effects of eating GM foods. Allergies? Possible effects of GM plants on ecosystems and biodiversity Lack of genetic diversity in transgenic plants could leave them vulnerable to new diseases or pests. Effects on natural plant pollinators like bees and butterflies. Cross pollination between transgenic plants and natural plants.

Cloning A clone is a genetically identical copy of a gene or an organism Cloning occurs in nature Bacteria (binary fission) Some plants (from roots) Some simple animals (budding, regeneration)

Cloning mammals Process called nuclear transfer Nucleus is removed from an egg cell Nucleus from a cell from the animal to be cloned is implanted in the egg

Pros/Cons of Cloning Benefits Concerns Organs for transplant into humans Save endangered species Low success rate Clones “imperfect” and less healthy than original animal Decreased biodiversity

http://www.youtube.com/watch?v=-Qry1gYYDCA

9.5 & 9.6 Genomics & Gene Therapy Genomics: Is the study of genomes (all of an organisms DNA) This has provided a big step in understanding evolution. The Human Genome Project: (2003) scientists mapped and sequenced all of the DNA from a few humans to figure out our common base pairs of the entire set of chromosomes. http://www.youtube.com/watch?v=N4i6lYfYQzY Gene Therapy: the replacement of a defective or missing gene, or the addition of a new gene into a person's genome to treat a disease. https://www.youtube.com/watch?v=bLI1Gfb0ynw

Gene Therapy: This is a promising treatment option for inherited genetic disorders & certain types of cancers, but it is still in the experimental phase.