Manipulating DNA Selective Breeding Man has selectively bred

Manipulating DNA

Selective Breeding • Man has selectively bred plants and animals for desired traits

Mutations of Pointsettias induced by radiation

New DNA Technology • Now DNA can be manipulated to produce new combinations not found in nature • How far should we go? – We need to set bioethical limits

Restriction Fragment Length Polymorphism (RFLP) Analysis • DNA is cut into small pieces using restriction enzymes • Many copies are made using PCR • Radioactive probes attached to mark ends • An electric current is used to separate pieces by size in a gel – Larger pieces are slower and don’t move as far down the gel http: //www. sumanasinc. com/webcontent/anima tions/content/gelelectrophoresis. html

DNA Fingerprinting • DNA is unique for every individual • Comparing the sequences of small pieces of DNA can be used: – Find relationships – Narrow crime suspects – Identify organisms

Tools needed in Gene Cloning • Restriction enzymes – Cuts the desired DNA strands • Bacterial plasmid – cloning vector used to move DNA to another organism • Host DNA – Donor gene(s) Produces a transgenic organism with recombinant DNA

Clones • Copies of one organism

Clones • Produced by taking cuttings from one plant – Grafting – Budding – Rooted cuttings

Clones • Produced for many years by dividing an embryo to form identical quadruplets – Cows – Pigs

A New Type of Clone • The nucleus of a donor cell • The ova (egg) of another organism • A surrogate mother

How it’s done…

FDA says cloned animals safe to eat • Food producers, including Tyson Foods Inc. and Dean Foods Co. , said they won't use cloned foods anytime soon. • Bloomberg News / January 16, 2008 • WASHINGTON - Cloned cows, pigs, goats, and their offspring are safe to enter the US food supply, regulators said over protests from lawmakers, consumer groups, and worried eaters.

Maryann Mott for National Geographic News April 4, 2006 Meet Royal Blue Boon Too, the first commercially cloned horse in the United States. The cost of the frisky foal: U. S. $150, 000. That may be a bargain, considering that the original Royal Blue Boon, a 26 -year-old American Quarter Horse now past breeding age, has earned more than $380, 000 as a competition and show horse. Champion Horse Cloned by Texas Breeder .

Controversial topics… • Scientists hope to use cloned embryos to harvest precious "stem cells" — cells that, in theory, can ultimately grow into any kind of cell in the body. • These cells could be used to generate new organs or cell clusters to treat patients with failing organs or degenerative diseases • In the case of transplant patients, organs made from exact copies of an individual's own cells and would not be rejected. • This research is still in its earliest phase of development. All of the embryos generated actually died — none grew beyond the six-cell stage • Controversial: The thinking is that by allowing any kind of cloning of human embryos, it is then not such an enormous leap to apply the same techniques to making copies of people.

Some problems to Overcome: • Many casualties – Birth defects – Failures – Premature aging • Improve technique