1. Changing the Living World
Chapter 13
Changing the Living World

2. Selective Breeding
Selective breeding allows only those organisms with desired characteristics to produce the next generation.
Nearly all domestic animals and most crop plants have been produced by selective breeding.
Hybridization is the crossing of dissimilar individuals to bring together the best of both organisms.
Hybrids, the individuals produced by such crosses, are often hardier than either of the parents.
Inbreeding is the continued breeding of individuals with similar characteristics.
Inbreeding helps to ensure that the characteristics that make each breed unique will be preserved.
Serious genetic problems can result from excessive inbreeding.

3. Mutation
Mutation can occur during selective breeding practices in order to change the DNA of an organism
Not all mutations are bad!!!
Some examples of useful mutations
New kinds of bacteria (digest oil from spills)
New kinds of plants (stronger and larger)
Super Heroes!!!

4. Genetic Engineering
Genetic Engineering: making changes in the DNA code of a living organism.
DNA Extraction
Cutting DNA
Separating DNA

6. DNA Extraction
DNA can be extracted from most cells by a simple chemical procedure
The cells are opened and the DNA is separated from the other cell parts

7. Most DNA molecules are too large to be analyzed, so biologists cut them into smaller fragments using restriction enzymes
Each restriction enzyme cuts DNA at a specific sequence of nucleotides
These sequences can then be placed into other cells to create a desired effect known as Recombinant DNA

8. Making more DNA
Polymerase chain reaction (PCR) is a technique that allows biologists to make copies of genes
Small amounts of DNA can be multiplied making it easier to analyze

9. Gel Electrophoresis
Allows us to separate DNA fragments to identify genetic code
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 (negative) move towards the positive end of the gel.
Smaller the DNA the farther and faster it moves.
Used to identify gene composition of different organisms or identify 1 particular gene.

10. Gel Electrophoresis

11. Genetic Engineering
Transgenic: organisms that contain genes from other species
Microorganisms- bacteria
Animals- mice injected with human genes
Plants- soybeans and corn

12. Transgenic

16. Cloning
Clone: member of a population of genetically identical cells produced from a single cell.
First animal cloned-sheep Ian Wilmut

17. Cloning

18. Cloning
Researchers hope cloning will enable them to make copies of transgenic animals and help save endangered species.
Studies suggest that cloned animals may suffer from a number of genetic defects and health problems.