4.2 Selecting Desirable Traits

1. 4.2 Selecting Desirable Traits • Artificial Selection - is the process of selecting and breeding individuals with desirable traits to produce offspring with the desired traits. • Ex: Humans select which traits are bred and which traits are not. • Crops that produce more grain and are heartier are selected to reproduce. • Beefier cows are selected to reproduce • The selection process is simple. Only those individuals, with the desired trait, will be allowed to reproduce. • This selection process also applies to plants, which can be bred to possess desirable traits. • The main difference between 'natural' selection and 'artificial' selection is that, humans control the artificial selection process.

2. Biotechnology is the process of intervention to produce more desirable organisms Has been going on for some time. Practised by early Native people when they chose seeds from the biggest and healthiest corn plants. Artificial selection may take a long time to see results - usually many generations. Farmers, dog and horse breeders, along with scientists can now speed up the artificial selection process by using 'low-tech' or 'high-tech' technologies, such as: cloning (made from cells) artificial insemination (artificially joining the male and female gametes) in vitro fertilization (male and female gametes are selected and then allowed to fertilize in a controlled setting) genetic engineering (directly altering the DNA of an organism) Biotechnology

3. The simplest way to clone a plant that is displaying desirable traits is to use a cutting, which will grow into an identical plant. A quicker way to clone a plant is by removing cells from one plant placing them into a Petri dish containing nutrients and hormones. Some these cells will develop into seedlings and then can be transplanted into the soil. 1. Cloning Plants

4. 2. Artificial Insemination • Most livestock in Canada are artificially inseminated. • Sperm Cells are harvested from a bull with desired characteristic and are inserted into many female cows. • Advantages: Sperm can be in several places at once and more cows can be inseminated.

5. 3. In Vitro Fertilization • Sperm cells from a prize bull and eggs from a prize cow are harvested from the animals. • In a laboratory, the eggs and sperm are placed in a Petri Dish, and the eggs are fertilized by injecting the sperm cells into the eggs cells. • Embryos develop and are then transplanted into a different cow. • Advantages: • Scientists can determine the sex of the embryos thereby guaranteeing all the calves will be female.

6. 4. Genetic Engineering • Genetic engineering refers to any technology that directly alters the DNA of an organism. • Involves inserting a gene from one species into another species. • Ex: Bacteria are genetically engineered to produce life-saving medicines such as insulin. • Bacillus thuringiensis (BT) is a micro-organism that produces a toxin which is poisonous to many insects. Scientist have isolated the BT toxin gene and have inserted it into some plants to act as a built in pesticide. • Insects eating these BT plants die! Golden rice has also been engineered to contain vitamin A to improve nutritional diets to third world nations.

7. Beneficial or detrimental to society? That is one of the pressing questions that many humans are struggling with. when it comes to biotechnology. There are many good things that can be produced, but what about the problems, including: risks in animals (reducing genetic variation within a specific population, less resistance to disease, birth defects and other abnormalities) risks in plants (resistance to herbicides) Biotechnology and Society

8. Risks to Animals? • In agriculture, most livestock populations are extremely similar as a result of generations of artificial insemination. • Reduced variation = susceptible to disease • Scientists are now able to produce and identical copy of a single animal. • Dolly the sheep was produced in Scotland in 1997 and is an exact duplicate of her mother. • Herds of cloned animals become far more susceptible to disease than genetically variable herds. • Cloning isn’t perfect and has had problems with unsuccessful pregnancies, birth defects, and deaths. Dolly herself has developed arthritis even though her “parent” has not! Why?

9. Dolly Poem • A Cloning Poem • Mary had a little lamb, its fleece was slightly gray,It didn't have a father, just some borrowed DNA.It sort of had a mother, though the ovum was on loan,It was not so much a lambkin, as a little lamby clone.And soon it had a fellow clone, and soon it had some more,They followed her to school one day, all cramming through the door.It made the children laugh and sing, the teachers found it droll,There were too many lamby clones, for Mary to control.No other could control the sheep, since their programs didn't vary,So the scientists resolved it all, by simply cloning Mary.But now they feel quite sheepish, those scientists unwary,One problem solved, but what to do, with Mary, Mary, Mary! • http://www.juliantrubin.com/cloningjokes.html

10. Most of our plant crops were produced by artificial selection of wild plants. Weeds are often the wild relatives of crop plants. Some crops have been genetically engineered to resist herbicides. Many crop plants however, can still cross fertilize with their wild weed relatives producing offspring weeds that are resistant to herbicides. Risks to Plants

11. Homework Assignment Read Pages 66 - 71 Check and Reflect Page 71 Questions 1 - 7 http://www.cartoonstock.com/directory/g/genetics.asp