Selective Breeding & Genetic Engineering

What we want to learn!

•Summarize how transgenic organisms are engineered to benefit society.

•Explain how transgenic organisms are used in agriculture, industry, and medicine.

Selective Breeding•For thousands of years, humans have

selected plants and animals with certain qualities or desired traits.

•They’re bred with other plants and animals with desired traits.

•The same principle is applied today to the food we eat and the animals that we raise!▫Selective Breeding-selected organisms

bred with one another to produce offspring with desired traits.

Selective Breeding Examples•Seeds from the largest heads of grain•Seeds from the juiciest berries•Raise the calves of the best milk

producers •Save the eggs of the best egg laying hen

for hatching..........all of these examples show you how selective breeding is done! ………the goal is to try and ensure your outcome is the animal or plant of choice!

Selective Breeding•This process takes time and multiple

generations before the desired result is reached.

Desired Result: a population breeds consistently so that each member shows the desired trait.

Interbreeding•Interbreeding-mating between closely

related organisms▫Results: an organism that has the same

genes for each trait! This organism is almost guaranteed to now have the desired traits!

▫ie. pure bred dogs▫ie. Pure bred horses

•Hybrids- the result of the interbreeding▫Usually higher functioning, larger &

stronger than their parents.

Genetic Engineering•Genetic Engineering is a faster, more

reliable method of increasing a desired trait

•DNA is cut – or cleaved from one organism into small fragments and inserted into a host of the same or different species

......Genetic engineering is also referred to as recombinant DNA technology

▫Recombinant DNA- connecting, or recombining, fragments of DNA from different sources.

Original plasmid has a enzyme recognition site.

The plasmid is then cut by the enzyme (ie.Eco R1) ; when DNA is cut, you end up with double stranded fragments with single stranded ends.

Foreign DNA is then inserted into the plasmid ; giving you a recombinant plasmid (recombinant DNA)

Transgenic organisms contain recombinant DNA

•Recombinant DNA can be inserted into a organism’s chromosomes ▫Chromosomes: carries your genetic

information•That organism will use this foreign DNA

as its own.

Restriction Enzymes• Isolate the foreign DNA fragment that will be

inserted.▫Restriction enzymes are proteins that have the

ability to cut both strands of the DNA at specific areas.

• Attach DNA fragment to the carrier▫Vectors: carries the DNA into the (host) DNA▫ie. The glowing tobacco leaf ; light producing

DNA had to be placed into a bacterial vector before it could be inserted inside the plant

• Transfer into host organism.▫Plasmid-small ring of DNA found in a bacterial

cell

Vectors •…so far we’ve learned that restriction

enzymes cut the DNA that is taken from organism A.

•If the same restriction enzyme is used to cleave the plasmid the DNA of organism A should join together with the plasmid ring.

First in this diagram you have the plasmid vector. The

Gene cloning•After desired genes and desired are

“united”..the recombinant DNA is then cloned.

•The plasmid is capable of replicating separately from the bacterial host.

•DNA is reproduced quickly.

DNA Technology