Download Ch. 15

• breeding of organisms to produce
certain desired traits in their
offspring.
• http://www.youtube.com/watch?v
=_ZbnfjLoDSY
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The differences among breeds of dogs are great. Where did
these differences come from?
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Humans use selective breeding to produce animals with
certain desired traits. Selective breeding allows only those animals
with wanted characteristics to produce the next generation.
•
American botanist Luther Burbank developed more than 800
varieties of plants using selective breeding methods.
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One method Burbank used was hybridization, crossing
dissimilar individuals to bring together the best of both organisms.
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Hybrids—the individuals produced by such crosses—are often
hardier than either of the parents.
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To maintain desirable characteristics in a line of organisms,
breeders often use inbreeding, the continued breeding of
individuals with similar characteristics.
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The many breeds of dogs are maintained using inbreeding,
ensuring that the characteristics that make each breed unique are
preserved.
• Application of a technological
process, invention, or method to
living organisms.
It is relatively easy to extract DNA from cells and
tissues.
The extracted DNA can be cut into fragments of
manageable size using restriction enzymes.
These restriction fragments can then be separated
according to size, using gel electrophoresis or another
similar technique.
•
Once biologists find a gene,
a technique known as
polymerase chain reaction
(PCR) allows them to make
many copies of it.
• 1. A piece of DNA is heated,
which separates its two
strands.
• 2. At each end of the original
piece of DNA, a biologist adds
a short piece of DNA that
complements a portion of the
sequence.
•
These short pieces are
known as primers because they
prepare, or prime, a place for
DNA polymerase to start
working.
• 3. DNA polymerase copies the
region between the primers.
These copies then serve as
templates to make more copies.
• 4. In this way, just a few dozen
cycles of replication can
produce billions of copies of the
DNA between the primers.
• Genetic Engineering- any technique used to identify or
change genes.
• Examples: Corn, Tomato, Cows
• Gel Electrophoresis- using electric currents to separate
fragments or bases of DNA.
• Gene Cloning- making an exact copy of a living organism.
• Example- Dolly- first cloned mammal from a body cell.
•
• Stem Cells- primitive cells that can be cultured
into tissues or organs.
• Examples:
• Adult- umbilical cord
• Embryonic- developing embryos
• Human Genome Project- project to map
every human chromosome.