<>Horticulture and the Science of Plants ><>
<> Horticulture Youth Adventure Program >
<> David Wm. Reed, Instructor >
<> Department of Horticultural Sciences>
<>Texas A&M University>
What is a Gene?
Every plant and animal obtain their genes from their parents; 1/2 from the female parent and 1/2 from the male parent. Genes are made up of DNA. Genes determine everything about a plant or animal. For example, if you have blue eyes it is because you have the gene that determines blue eyes. How do genes do this? Genes contain DNA which is the blueprint for how to make special compounds called enzymes. Enzymes are special types of proteins that are responsible for making compounds, such as the blue pigment in blue eyes. Thus, if you have the gene for blue eyes, then you can make the enzyme that makes the blue pigment and you will have blue eyes. There is a gene that determines everything about every plant and animal.
What is genetic engineering and a GMO?
Up until recently, a plant or animal could only get its genes from its parents. However, genetic scientist, which are often called molecular biologist, have learned how to take genes out of one organism and put them in another organism. So now genetic scientist can change plants and animals by giving them new genes. This is called genetic engineering, which is the manipulation of an organism's genes. If a plant or animal has its genes changed or if it gets new genes by genetic engineering, then it is called a genetically modified organism or GMO.
Example of a Plant That is a Genetically Modified Organism (GMO)
There is a bacteria called Bacillus thuringiensis that causes a disease in certain types of caterpillars. When the caterpillar comes in contact with the bacteria, its gets the disease and dies. Genetic scientist took the gene that is responsible for the disease out of the bacteria and put the bacteria gene in a cotton plant. So now the cotton plant contains the gene that causes the disease and when caterpillars eat the cotton leaves the caterpillars will die. The cotton is called BT cotton. Thus, genetic engineering is used to make BT cotton plants poisonous to caterpillars and farmers do not have to spend money to spray pesticides to kill the caterpillars.
Genetic Engineering is Very Controversial
Genetic engineering is very controversial. Why? Because some people believe that it is not natural and unethical for scientist to change the genes in a plant or animal. For example, genetic engineering can make hybrids between two totally different kinds of organisms, such as the Bacillus thuringiensis bacteria and a the cotton plant. Some people feel these kinds of genetically modified plants can be dangerous. Others believe that genetic engineering is an excellent way to make plants grow faster or be more nutritious, so they may help prevent world hunger. Each person has to come to their own conclusion as to whether or not they are for or against genetically modified organisms.
Cloning is where cells are taken form an organism and the cells are tricked into making a duplicate organism. The duplicate organism would be called a clone. We have been cloning plants for centuries. You can go in to a vegetable garden and cut the stem off a tomato plant. If you put the tomato stem in a glass of water in the window of your kitchen, the stem will make new roots and produce a new plant. The new plant will be a clone of the tomato plant in the garden. If you cut-off 10 stems, then you will have 10 new tomato plants that are clones of the tomato plant in your garden. If you used tissue culture to grow the new plants, you could produce hundreds of thousands of clones in one year. We do this all the time with plants.
A greenhouse full of poinsettia clones.
Recently, genetic scientist have developed the ability to clone animals. The first cloned animal was Dolly the sheep. Since then cattle, goats, pigs, cats, rats, monkeys, and others have been cloned.
There are rumors that some genetic scientist in other parts of the world are trying to clone humans. Cloning of animals is controversial, and cloning of humans is extremely controversial. As with genetically modified organisms, each person has to come to their own conclusion as to whether or not they are for or against cloning of animals, especially humans.
Animals that have been cloned.
Each plant or animal is unique because because they each have their own set of genes. There is only one David William Reed in this world because no other person has exactly my set of genes. Genes are composed of DNA, therefore each plant and animal's DNA is unique also. Scientist can take a few cells from a plant or animal, remove the DNA and determine its pattern. This pattern is a unique as a person fingerprint. Thus, the DNA fingerprint can be used to very accurately identify a plant or animal.
DNA fingerprint of corn. Each column is a fingerprint.
What are some uses of a DNA fingerprint:
TAKE HOME LESSONS
1) To learn what genetic engineering means.
2) To learn that a plant that has its genes altered or new genes added is called a genetically modified organism or GMO.
3) To learn how genetic scientist use genes and DNA to finger print plants.
4) To tour a genetic engineering lab to observe what genetic engineers do.
Tour the genetic engineering laboratories in the Norman Borlaug Crop Biotechnology Building
The class a tour of the laboratories in the Norman Borlaug Crop Biotechnology Building. During the tour we will see: