Chapter+13

Genetic Engineering

13-1 selective breeding- allowing animals with desired characteristics to produce the next generation. hybridization- crossing dissimilar individuals to bring together the best of both organisms. Inbreeding- the continued breeding of individuals with similar characteristics.

Key Points:
 * Purpose of selective breeding.
 * humans use selective breeding which takes advantage of naturally occurring gentic variations in desired plants, animals, and other organisms, to pass desired traits on to the next generation.
 * Why breeders try to induce mutations.
 * breeders can increase the genetic variation in a population by inducing mutations, which are the ultimate source of genetic variability.

13-2 Genetic engineering- making changes in the DNA code of a living organism. Restriction enzyme- enzymes that cuts DNA at a specific sequence of nucleotides. Gel electrophoresis- a procedure used to separate and analyze the DNA fragments by placing a mixture of DNA fragments at one end of a porous gel and applying an electrical voltage to the gel. Recombinant DNA- enzymes that make is possible to take a gene from one organism and attach it to the DNA of another organism. Polymerase chain reaction (PCR)- technique that allows molecular biologists to make many copies of a particular gene.

Key Points:
 * How scientist make changes to DNA
 * Scientist use their knowledge of the structure of DNA and its chemical properties to study and change DNA molecules.
 * Different 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.

13-3 Plasmids- small circular piece of DNA. Genetic marker- a gene that makes it possible to distinguish bacteria that carry the plasmid with foreign DNA from those that don't.

Key Points:
 * What happens during cell transformation.
 * A cell takes in DNA from outside the cell.
 * This external DNA becomes a component of the cell's DNA.
 * How can you tell if a transformation experiment has been successful.
 * The recombinant DNA is integrated into one of the chromosomes of the cell.

13-4 Transgenic- term used to refer to an organism that contains genes from other organisms. clone- member of a population of genetically identical cells are produced from a single cell.

Key Points:
 * How are transgenic organisms useful to human beings
 * genetic engineering has spurred the growth of biotechnology, which is a new industry that is changing the way we interact with the living world.