Genetic Engineering

Genetic engineering is defined as the manipulation or alteration of the genetic structure of a single cell or organism. This refers to addition, deletion or mutation of an organisms DNA or the transfer of a gene from one organism to another to produce a desired result.

What Is Biotechnology? Biotechnology refers to all forms of genetic engineering. The most common form of biotechnology involves adding the genes from one species to the genes of another different species to create a new species. The new species is called Transgenic or GMO (genetically modified organism) Selective breeding is NOT biotechnology

How are transgenic or GMO’s Produced? The use of bacteria cells is common: Bacteria cells have only one chromosome, a circular molecule of DNA. Bacteria may also have small, circular segments of extra DNA called Plasmids. In labs, foreign DNA can be inserted into a plasmid which will copy itself over and over, thus copying the inserted gene. or Restriction enzymes and modification enzymes make it possible to cut DNA and insert foreign DNA into bacterial cells.

Restriction enzymes Act as biological scissors

Example:Agrobacterium tumefaciens Ti plasmid Agrobacterium Genomic DNA Plant cell the gene of interest Genomic DNA (carries the gene of interest) + Ti plasmid with the gene of interest Gene of interest Empty plasmid A Restriction enzyme A

Agrobacterium Ti plasmid with the new gene Plant cell cell’s DNA Transgenic plant Cell division The new gene + Transformation Example:Agrobacterium tumefaciens

Real Examples of This: Synthetic genes for insulin have been transferred into E. coli cells. These cells then multiplied to form populations which were “factories” for the production of insulin (to be used by diabetics). Other drugs that are mass produced this way: human somatotropin (growth hormone) blood clotting factors hemoglobin Interferon (used to treat cancer) Interlukin (used to treat cancer)

Real Examples of This Cont: Bt gene in corn, cotton, and soybeans: insecticide properties - a genes have been inserted that are toxic to insect pests. Flavr Savr tomatoes: Shelf properties - gene have been inserted that extend the shelf life of fruits or vegetables so they can be stored longer. Many other crops: Herbicide resistance - allows growers to spray herbicide on crops as well as weeds – weeds die, but crops have herbicide- resistant gene, so they survive.

How common are GM foods? Over 48 foods have been approved for use. Products Corn Canola Potatoes Tomatoes Squash Soybeans Flax Cottonseed oil Sugarbeets Derived Products Corn syrup Tofu Canned foods Soya sauce Animals that feed on GMOs… …. AND MORE

How common are GM foods? LABELING OF GM FOODS IS NOT MANDATORY!

Potential Benefits of Genetic Engineering Improved farming Cheaper food More food Increased nutrition Reducing world hunger and improving world health Pest resistance Herbicide resistance Cold tolerance Drought tolerance Edible vaccines

Potential Hazards of Genetic Engineering Non-target organisms will be harmed - Bt corn and monarch butterflies “Superweeds” and “superpests arise -insect resistance and herbicide resistance create weeds and insects that can spread unchecked in nature and are immune to all sprays and biopesticides. Toxins & poisons -Genetic manipulation can increase the levels of natural plant toxins or create entirely new ones Increases cancer risk - rBGH and dairy cows Food allergies -exposure to foreign proteins spliced into foods could be harmful /fatal New viruses & pathogens Loss of biodiversity NO LONG TERM STUDIES YET!

Cloning Cloning is a form of genetic engineering that uses DNA of an existing individual (could be dead) to create a new individual that is a genetic duplicate. There are two types of cloning: Therapeutic cloning=uses stem cells, cloning of only tissues, cells or possibly organs Reproductive cloning = cloning of entire individual, implantation into surrogate mother and brought to term, producing offspring. Best known example of reproductive cloning is Dolly, a sheep that was cloned using DNA from a sheep that had been dead for six years.

Stem cell use in cloning What are stem cells? Stem cells are cells that can become other types of cells. There are two types: 1. Embryonic stem cells = Cells derived from a blastocyst which is a 5 -7 day old embryo. 2. Adult stem cells –Embryonic stem cells possess the attribute of pluripotency, which means they are capable of turning into any cell type. –Adult stem cells in some cases possess multipotency, which means they can develop into more than one cell type.