Transcript Selective Breeding

Selective
Breeding
• Have you ever watched a dog show?
• Many different breeds are presented.
• Judges look for the specific traits each
type of dog should have.
Think about this.
• Why are there so many
different breeds of dogs?
• How did some dogs get their
unique traits?
Dogs, dogs, and
more dogs
Dogs, dogs, and
more dogs
Dogs, dogs, and
more dogs
Dogs, dogs, and
more dogs
Dogs, dogs, and
more dogs
Dogs, dogs, and
more dogs
Dogs, dogs, and
more dogs
Dogs, dogs, and
more dogs
Dogs, dogs, and
more dogs
Dogs, dogs, and
more dogs
Dogs, dogs, and…
the DAWG!
Selective Breeding
• Humans have used genetic
patterns that occur naturally in
dogs to pass on desired traits to
the next generation. This is called
selective breeding.
• Selective breeding has been used
to produce faster race horses, new
varieties of plants, etc.
Selective Breeding
• Selective breeding has been used
to produce faster race horses, new
varieties of plants, etc.
• This is what Gregor Mendel did
with pea plants. He chose which
plants would reproduce with other
plants.
Inbreeding
• This type of selective breeding
is used to maintain, or keep,
certain traits in offspring.
• Similar individuals are crossed
in order to increase the chance
of the offspring having the
traits of their parents.
Inbreeding
• This sometimes causes
problems because it increases
the chance that an offspring
will inherit two recessive alleles
that may cause a genetic defect.
Inbreeding
• For example, some German
shepherds and Labrador
retrievers have joint problems
because of too much inbreeding.
Dachshunds may have heart
problems.
Hybridization
• This is where two individuals
with different traits are crossed
in hopes of getting the best
traits from both parents.
Hybridization
• Remember: hybrid is another
way to say heterozygous, or
different. It means different or
mixed.
Hybridization
• Suppose there was a type of
corn that was very drought
resistant and another type of
corn that had a great flavor.
What would you hope to get by
crossing those two varieties?
Examples of
Hybrid Animals
Liger
(see article)
Examples of
Hybrid Animals
Zebra +
Donkey =
Zedonk
Examples of
Hybrid Animals
Donkey
+ horse=
Mule
Genetic
Engineering
• This is where scientists take bits of
genetic material from one organism
and insert it into another.
Genetic
Engineering
• This is where scientists take bits of
genetic material from one organism
and insert it into another.
• They hope to someday use this
technique to cure genetic disorders.
• YouTube - Genetic Engineering
Animation
Genetic Disorders
Down Syndrome
Genetic Disorders
Sickle Cell
Genetic Disorders
Albinism
Genetic Disorders
Cystic Fibrosis
Cloning
• This involves using the genetic
information from one organism
to produce an exact copy of that
same organism.
• A sheep named Dolly was the
first mammal cloned.
Dolly
Ethics
Do you think scientists
should be experimenting
with and manipulating
genes?
•Cloning and genetic
engineering do not
occur naturally. They
happen in
laboratories.