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SELECTING DESIRABLE TRAITS ARTIFICIAL SELECTION ¢ The process of selecting an breeding individuals with desirable traits to produce offspring that have these desired traits. Humans choose, not nature! IN NATURAL SELECTION ¢ The environment “selects” traits. In artificial selection, humans select traits. ¢ For example, scientists working at Alta Genetics Inc. of Calgary were the first to use genetically engineered cattle that would produce more beef. REMEMBER THE GENETICALLY MODIFIED CHICKENS IN “VEGUCATED?” MOST OF WHAT YOU EAT IN A DAY IS PROBABLY A PRODUCT OF ARTIFICIAL SELECTION ¢ Grains ¢ Fruits ¢ Vegetables ¢ Meats ¢ Nuts CONSIDER HORSE BREEDING ¢ By combining genes of champion parents, breeders hope to create offspring that have the traits of both parents. IN A BREEDER’S POPULATION, EVERY INDIVIDUAL IS SELECTED IN THE SAME WAY… ¢ Only those with the trait the breeder wants will be allowed to breed. ¢ In contrast, natural selection, “selects” traits that are useful for the for the survival of the individuals with those traits and allows them to breed. NATURE VS NURTURE? ¢ The owner of a prize stud can earn about $30 million per year. NATURE VS NURTURE ¢ "The offspring of expensive stallions might tend to win more money, but not necessarily because they have inherited the best genes," said Wilson. ¢ "It is likely those breeders best able to pay high stud fees are also those who are able to spend more on care of the horse, how it is trained, and who rides it - all of which will contribute more to how much it will win." HUMANS PRACTICED ARTIFICIAL SELECTION FROM THE TIME WE FIRST BEGAN TO FARM ¢ About 10,000 years ago ¢ Most of our plants no longer resemble the wild species from which they were bred. ¢ E.g. Corn/Maize TEOSINTE BIOTECHNOLOGY ¢ Aboriginal peoples practiced an early form of biotechnology. THEY GATHERED SEEDS… ¢ From the biggest and healthiest corn plants. ¢ This benefited them because they were able to develop more productive strains of corn. ALTHOUGH ARTIFICIAL SELECTION HAS PRODUCED MOST OF WORLD’S CROPS AND LIVESTOCK… ¢ It takes a very long time (many generations) to get an organism with the desired combination of traits. FOR EXAMPLE… ¢ Livestock breeders have to breed cows over many generations to get a while herd that produces large quantities of milk. ¢ Scientists and breeders have developed technologies that can speed up this process. CLONES… CREATING PLANT CLONES ¢ The simplest way to create a clone is by taking a cutting from a plant and growing an identical plant from the cutting. THE DRAWBACK IS…. ¢ That this ideal plant has only so many leaves that can be cut off to use as cuttings. ¢ So scientists have developed a quicker way: cells are removed from an individual plant that has the particular traits that are wanted. ¢ These cells are placed on a Petri dish or bottle containing nutrients and hormones the cells need. ¢ Once these cells have developed into seedlings, they can be transplanted into the coil. ¢ Many more clones can be produced from a single plant this way. ARTIFICIAL REPRODUCTIVE TECHNOLOGY ¢ Is an artificial way of joining a male and female gamete. MOST LIVESTOCK IN CANADA ARE PRODUCED IN THIS WAY. ¢ In artificial insemination sperm are harvested from a bull desired characteristic and are inserted into many female cows. ¢ The advantage is the that the sperm can be in many places at once and more cows can be inseminated. IN VITRO FERTILIZATION ¢ In this technology, sperm from a prize bull and eggs from a prize cow are harvested from the animals, and in a lab, placed in a Petri dish. THIS PRODUCES MANY MORE EMBRYOS THAT COULD BE PRODUCED NATURALLY. ¢ Each embryo is implanted in a different cow. These cows will give birth to many calves, all of which will be brothers and sisters. SCIENTISTS CAN ALSO DETERMINE THE SEX OF THE EMBRYOS… ¢ Before ¢ By they are implanted in the cows. choosing only females, dairy farmers can be guaranteed that all of their calves will be female, rather than having to use their resources to raise unneeded males. FIRST HUMAN “TEST TUBE” BABY ¢ On July 25, 1978, Louise Joy Brown, the world's first successful "test-tube" baby was born in Great Britain. USING A LONG, SLENDER, SELF-LIT PROBE CALLED A "LAPAROSCOPE," … ¢ Dr. Steptoe took an egg from one of Lesley Brown's ovaries and handed it to Dr. Edwards. ¢ Dr. Edwards then mixed Lesley's egg with John's sperm. ¢ After the egg was fertilized, Dr. Edwards placed it into a special solution that had been created to nurture the egg as it began to divide. PREVIOUSLY… IT TOOK MORE THAN ONE TRY TO GET THE SCIENCE RIGHT… ¢ Drs. Steptoe and Edwards had waited until the fertilized egg had divided into 64 cells (about four or five days later). This time, however, they decided to place the fertilized egg back into Lesley's uterus after just two and a half days. ¢ Close monitoring of Lesley showed that the fertilized egg had successfully embedded into her uterus wall. WHY WAS THIS NEW TECHNOLOGY CONSIDERED BENEFICIAL (A GOOD THING) ¢ For human beings? ¢ What concerns/potential problems can you identify? GENETIC ENGINEERING ¢ Refers to any technology that directly alters the DNA of an organism. ¢ A rapidly developing science, and every new advance increases our ability to control the characteristics of organisms. GLOFISH…IS A PATENTED AND TRADEMARKED BRAND OF GENETICALLY MODIFIED FISH. MONSANTO ¢ Video Link MANY OF THE GENETIC ENGINEERING TECHNIQUES… ¢ Involve inserting a gene from one species into another species. ¢ Bacteria are genetically engineered to produce life-saving medicines such as insulin. 20 YEARS AGO… ¢ Insulin had to be extracted from the pancreas of cattle and was expensive to produce. ¢ Today, the human insulinproducing gene is inserted into the bacteria’s DNA. BECAUSE BACTERIA REPRODUCE SO RAPIDLY… ¢ Bacteria cheaply. colonies can produce insulin quickly and BACILLUS THURINGIENSIS PRODUCES A TOXIN CALLED BT ¢ BT is poisonous to many insects. SCIENTISTS ISOLATED THE GENE THAT CONTAINS THE INSTRUCTIONS FOR MAKING BT TOXIN… ¢ And have inserted it into the DNA of plants. ¢ These genetically engineered plants now produce Bt toxin. ¢ Since the 1990s, cotton, corn, and potatoes have been engineered to produce Bt toxin. ¢ Because insects that eat the engineered plants die, farmers never have to use pesticides to engineered plants. SOME VARIETIES OF CANOLA ARE NATURALLY RESISTANT TO FLEA BEETLE, WHILE OTHERS ARE NOT. ¢ The most valuable varieties are not naturally resistant, so most growers use pesticides. ¢ Why might this be a problem? ¢ Scientists have just figured out how to transfer the resistance gene to non-beetle resistant varieties. BIOTECHNOLOGY AND SOCIETY ¢ As with any technology, there are risks and benefits. ARTIFICIAL REPRODUCTIVE TECHNOLOGIES … ¢ Can reduce the variation in breeding lines of livestock; the sperm of just a few animals is used to impregnate many females. ¢ With in vitro fertilization, the embryos created from the eggs and sperm of just 2 individuals is implanted in many other cows. CLONING… ¢ Remember “Dolly” the sheep? ¢ Produced in 1997, Dolly was an exact duplicate of her mother. Dolly’s cells appear to be the same age as her mother’s, even though Dolly is 6 years younger. ¢ Herds of such genetically identical individuals may be far more susceptible to disease than more genetically variable herds. CLONING AND GENETIC ENGINEERING… ¢ Are in their infancy and have been full of problems. ¢ Some researchers hypothesize that something about the process of removing the nucleus from the donor egg may be responsible. CATTLE CLONERS… ¢ Have reported many examples of unsuccessful pregnancies, birth defects, and deaths.