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Biotechnology

Chapter 13

+I. Selective Breeding

A. Desired traits of certain plants and animals are selected and passed on to future generations

Saint BernardRescue dog

HuskySled dog

German shepherdService dog

+II. Genetic Engineering

A. Technology1. Involves manipulating DNA of

one organism to insert DNA of another organismi. Exogenous DNA

+II. Genetic Engineering cont.

A. Genetically engineered organisms are used

1. Study the expression of a particular gene

2. Investigate cellular processes3. Study the development of a certain

disease4. Select traits that might be beneficial

to humans

+III. DNA Tools1. Organism’s genome

A. Total DNA in the nucleus of each cell2. DNA tools

A. Manipulate DNAB. Isolate genes from the remaining genome

3. Types of DNA toolsA. Restriction enzymes (RE) – EndonucleasesB. Recombinant DNAC. Gel ElectrophoresisD. Gene sequencing E. PCR

+IV. Restriction Enzymes

A. Restriction enzymes (endonucleases)1. Recognize and bind to specific DNA

sequences2. Cleave (cut) DNA within a sequence

B. Scientists use restriction enzymes1. Isolating specific genes or regions of

the genome.

+IV. Restriction enzymes cont.A. Example of restriction enzymes (endonucleases)

1. EcoRI specifically cuts DNA containing the sequence GAATTC

B. Ends of DNA fragments (sticky ends)A. Contain single- stranded complementary DNA

+I. Making Recombinant DNA

A. Cut DNA using restriction enzymeB. Cut bacteria plasmid using same restriction

enzyme C. Insert plasmid with desired gene into bacteria

1. TransformationD. Clone the bacteria cellE. Isolation

1. Kill off unwanted bacteria (use antibiotics)2. Bacteria without desired gene

+II. Recombinant DNAA. Newly generated DNA molecule with DNA

from different sourcesB. Use plasmid from bacteriaC. Isolate genomic DNA

+III. Make large quantitiesA. Bacterial cells are mixed with recombinant

plasmid DNAB. Bacterial cells take up the recombinant

plasmid DNA1. Called transformation

+IV. Cloning A. Large numbers of identical

bacteria, each containing the inserted DNA molecules, are produced

+I. Gel Electrophoresis

A. An electric current used to separate DNA fragments

B. Based on size of fragmentsC. Electric current forces DNA fragments

to move toward the positive end of gel

D. Smaller fragments move farther & faster than the larger ones

+Picture of Setup

+II. Setup/ Equipment

A. Power supplyA. Has positive and

negative sides1. + molecules go towards –

side2. - molecules go towards +

side

B. Agarose Gel1. Highly purified and

uniformly sized slide molecules made from seaweed

A. Buffer1. Salt water

i. Lets electric current run through gels

B. Wells1. Place where sample

is added to the gelC. Micropipette

1. Used to load sample into gels

+III. Loading a Gel

A. Use micropipette

1. Measures in millionths of liters (microliters)

B. Samples1. In microfuge

tubes

+IV. Reading a Gel

A. Unique pattern can be compared to known DNA fragments for identification

B. Based on fragment size

Gel electrophoresis

+V. DNA Fingerprinting

A. Protein-coding regions of DNA are almost identical among individuals

B. Noncoding regions of DNA are unique to each individual

C. Separating noncoding DNA fragments to observe distinct banding patterns unique to every individual

+I. DNA Sequencing

A. Mix an unknown DNA fragment, DNA polymerase, and the four nucleotides—A, C, G, T in a tube.

+I. DNA Sequencing cont.

B. Each nucleotide is tagged with a different color of fluorescent dye

C. Every time a modified fluorescent-tagged nucleotide is incorporated into the newly synthesized strand, the reaction stops

+I. DNA Sequencing cont.

D. Sequencing reaction is complete when tagged DNA fragments are separated by gel electrophoresis

+II. Polymerase chain reaction (PCR)A. Used to make millions of copies

of a specific region of a DNA fragment.

+

+I. Transgenic Animals

Scientists produce mostly for biological research

Genetically engineered by inserting a gene from another organism

Mice, fruit flies, and the roundworm Caenorhabditis elegans

+II. Transgenic Plants

Genetically engineered cotton Resists insect infestation of the bolls

Sweet-potato plants Resistant to a virus that could kill most of the African harvest

Rice plants Increased iron and vitamins that could

decrease malnutrition