Download 13-1 Changing the Living World

Chapter 13: Genetic Engineering (13-1)
Dog breeds are NOT different species.
 Selective Breeding—allowing only those animals
with desired characteristics to produce the next
generation.
 Humans use selective breeding to pass desired
traits on to the next generation of organisms.
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Hybridization—crossing dissimilar individuals to
bring together the best of both organisms.
 hardier than either parent (hybrid vigor)
 disease resistant
 mule, lyger, etc.
Inbreeding is the continued breeding of individuals
with similar characteristics
o breeds of dogs are maintained through
inbreeding
Due to genetic similarity—the greater the chances
the recessive alleles come together and produce
genetic defects.
o Hip problems, blindness, other deformities
Chapter 13: Genetic Engineering (13-1)
Natural populations have tremendous diversity
 Breeders can increase the genetic variation in a
population by inducing mutations, which are the
ultimate source of genetic variability.
 Radiation and chemicals are used to increase
mutations
 Most mutations are harmful, but with luck few
mutations can be desirable..examples:
 New kinds of bacteria (eat oil!)
 New kinds of plants…
 polyploidy –double or triple the amount
of chromosomes
 Fatal in animals
 Produces new species of plants
(larger/stronger)
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