Chapter 13 Genetic Engineering
Genetic Engineering is making changes in the DNA code of a living organism.
Selective breeding is when humans only use the animals with desired characteristivs to produce the next generation so that they only have the certain traits that they want them to have.
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Hybrids- Hybridization is the crossing of dissimilar individuals to bring together the best of both organisms. Most hybrids are hardier than either of the parents.


Inbreeding- Inbreeding is the continued breeding of individuals with similar characteristics. This is how most dogs are bred. The drawbacks of inbreeding are that with the same traits parents might pass on a recessive trait that causes genetic diseases. Pure breed dogs can have epilepsy, blindness, joint deformities, and many other unfortunate and possibly painful things wrong with them.

external image bananas.jpgexternal image 1.jpgIncreasing Variation- breeders can increase the genetic variation in a population by inducing mutations, which are the ultimate source of genetic variability. Increasing variations is one of the techniques that has been very useful in producing new kinds of bacteria. One such species of bacteria is able to digest oil, which helps in the clean-up of spills.

Polyploid Organisms- Plants that grow from drugs that prevent cromosomal separation during meiosis are called polyploid. Polyploid animals normally die because of the extra chromosomes, meanwhile pants can tolerate the extra chromosomes creating new species that tend to be hardier then their diploid relatives. For this reason, many crop plants are produced this way.

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Scientists can change DNA molecules and study them using their knowledge of its structure and its chemical properties. There are several techniques that are used to do many things to DNA, such as: extract DNA from cells, cut DNA into smaller pieces, identify the sequence of bases in a DNA molecule and to make unlimited copies of the DNA. It also can be spliced into other stands of DNA to create organisms that can produce things they shouldn't be able to, or do things that wouldn't be otherwise possible. One example of this is goats that have a gene from spiders that allows them to create web in their milk.

There are enzymes called restriction enzymes; there are hundreds of them. Each one cuts DNA at a specific sequence of nucleotides.

Gel electophoresis is when a mixture of DNA fragments is placed at one end of a porous gel, and an electric voltage is applied to the gel. When the power is turned on, the DNA molecules are negatively charged, they move toward the positive end of the gel. Gel electophoresis can be used to compare the genomes of different organisms or different individuals. Also, it can be used to lovate and identify one particular gene out of the millions of genes in an individual's genome.

Cloning- the creating of genetically identical cell produced from a singe cell. The first clone was a sheep created by Ian Wilmut, a Scottish scientist, in 1997. The scientific community was shocked; it wasn't supposed to be possible. The cloned sheep, Dolly, was still able to reproduce normally; Bonnie was her first offspring. This could help save endangered species as well as keeping transgenic organisms alive as a species. Why would you want transgenic organisms alive as a species? They produce things, such as human growth horomones, that improve our lives. Did you know?- twins are the closest thing to natural cones- Now you know.

Transgenic Organisms- organisms with genes from other organisms. Transgenic animals are used to study genes and improve food supply. Mice have been produced that have immune systems that act similar to humans' because of the human genes that have been spliced with their genes. This helps us study the affects of diseases without harm to humans. Transgenic livestock with extra copies of growth hormone genes grow faster and produce meat that is less fatty than ordinary livestock. Transgenic plants are now important in our food supply. In 2000, 52% of soybeans and 25% of corn grown in the US were transgenic. Many transgenic pants have genes that produce natural insecticide and thus don't have to be sprayed. Others contain genes making them resistant to herbicides, allowing farmers to control the weeds without killing the crops. There is no a rice plant that adds Vitamin A to the rice. Transgenic microorganisms now produce such things as insulin, growth hormone, and clotting factor. Because of their rapid reproduction, those things that used to be rare and expensive are now cheap and in great abundance. Are transgenic organisms going to cause more harm than good? That's the question.


















Scientist use their knowledge of the structure of DNA and its chemical properties to study and change DNA molecules . Diffrent techniques are used to extract DNA from cells, to cut DNA into smaller pieces to identify the sequence of bases in a DNA molecule,and to make unlimited copies of DNA .
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Genetic Engineering is nothing new. It was discovered long ago by plant breeders when they learned how to alter seeds but in 1944 Oswald Avery Colin McLeod and Maclyn McCarty discovered that DNA was the carrier of genetic information. However the breakthrough came in 1953 when Watson and Crick decoded the structure of the DNA, important to the history of genetic engineering.

Genetic Engineering is very mysterious. It's all about trying to accomplish the impossible. Creating the perfect race. However with so many imperfections finding an antidote to cure cancer, diseases, infections, viruses, etc. is a lot more easier said then done. Some could say that Genetic Engineering is inhumane. Why? Because some would think it's going against god's will. Some people think that god has a plan for us all in life which would be like a "destiny". That there is reason for somebody to get cancer and for a little kid to not live past 10. However there is disagreements between those people and scientists. Therefore there are people that are Pro-natural and others that are Pro-Science.