Transcript 13.1x - Biology-RHS

Chapter 13
 Selective Breeding is used to produce
organisms with desired traits
 Dogs have been breed for hundreds of
years to do certain tasks : Saint Bernard—
Keen sense of smell, Husky--- endurance
to run long distances, German shepherd-- high trainability
 Two types of breeding patterns in Selective
breeding
 Hybridization used to give organisms a
competitive edge. Organisms can be bred
to be more disease-resistant, produce
more offspring, or grow faster
 Inbreeding process in which two closely
related organisms are bred to have the
desired traits; to eliminate the undesired
ones in future generations
 Genetic engineering is used to manipulate the DNA of
one organism in order to insert exogenous DNA (the
DNA of another organism)
 Researchers have inserted a gene for a bioluminescent
protein called green fluorescent protein (GFP) into
several different organisms; these organisms then glow
green under a black light
 Genome is the total DNA present in the nucleus of
each cell.
 Restriction enzymes are enzymes that recognize and
bind to specific DNA sequence and cleave the DNA
within that sequence
 They are used as powerful tools for isolating specific
genomic DNA, it creates fragments of different sizes that
are unique to every individual
 Gel Electrophoresis uses an electric current to separate
the DNA fragments according to the size of the
fragments
 Smaller fragments move farther faster than the larger
ones
 When DNA fragments are separated by gel
electrophoresis, specific fragments can be removed
and combined with DNA fragments from another
source this is called Recombinant DNA
 Recombinant DNA allows scientists to study
individual genes
 Plasmids are small, circular, double-stranded DNA
molecules that occur naturally in bacteria and yeast
 DNA ligase is used to join the two DNA fragments
chemically
 PCR is used to make millions of copies of a specific
region of a DNA fragment
 PCR is useful because this single DNA molecule then
can be copied, or amplified, numerous times to be
used for DNA analysis
 Transgenic Organisms are genetically engineered by
inserting a gene from another organism into another
organism
 Transgenic animals, plants, and bacteria are used not
only for research, but also for medical and agricultural
purposes