Download Applied Genetics

Applied Genetics
Selective Breeding and
Genetic Engineering
Selective Breeding
• = crossing of plants or animals that
have desirable traits to produce
offspring with those traits
• Increased strength
• Leaner meat (less fat)
• Disease resistance
• Larger grain/fruit
• Better taste
hybridization
• = crossing two organisms (same
genus/species, “kind”) with
variations of particular trait(s)
to produce offspring with a
mixture of the trait(s)
• Offspring inherits traits of both
parents
• Donkey X horse = mule
• Modern grains – corn, wheat
• Ancient wild wheat X wild goat
grass = nutritious hybrid wheat
used for bread
• The greater the difference between
“kinds” (genus/species) being
hybridized, the more likely the
hybrid will be sterile
Hybridization
• McIntosh X
Red Delicious =
Empire
Inbreeding
• = crossing 2 organisms that have
the same or similar trait(s) to
produce animals with the same
trait(s)
• Idea is to preserve the desirable
traits
• Organisms are genetically similar
and can lead to negative
consequences:
• Increased chances of inheriting
disorders
• Increased chances of contracting
certain diseases
• Decreased ability to adapt to
environmental changes
Interesting Hybrids
liger = cross between lion
(father) and tiger (mother)
Interesting Hybrids
• Tiglon = cross between male tiger and
female lion
• Beefalo/cattalo = bison x cow
• Hinny
• Female donkey x male horse
Cama = male camel x female
llama
Cloning
• A clone is an organism that has the
exact same genes as the organism
from which it was produced.
• African violet
• Sheep
• Pigs
Genetic Engineering
• Process in which genes
(sections of DNA) are taken
from one organism and
transferred to another
Recombinant DNA
• Section of DNA is separated from
strand of one organism
• This is spliced into the DNA of
another organism
• DNA is now combined
• Modified DNA will cause cells to
carryout processes in a different way
Products resulting from
genetic engineering
• Medicine
• Insulin, human growth hormone
(produced by altered bacteria)
• Hepatitis B vaccine (produced by
altered yeast cells)
Potential problems
• Cross-pollination of GM crops to
wild varieties can cause weeds to
become herbicide resistant
• Insects may become quickly
resistant to insecticides because
of exposure to GM crops
• Predators that eat insects who have
eaten GM crops can be affected in
unknown ways
• People who eat GM crops can be
affected in unknown ways
• Toxic effects
• Allergic reactions
• Resistance to antibiotics
Warnings
• Genes are now known to control more
than one trait
• By altering/changing a single gene,
multiple traits may be changed in ways
we can’t predict
• Human genes are only a small
percentage of the information contained
in DNA (5% or less)…we don’t know
what most of the rest does
The Future….
• Chimera – organism or
component composed of
different genetic material
• So far…
• Pigs with human blood
• Mice with human brain cells
• Sheep with human tissues in
hearts & livers
• Fusion of human & rabbit biomatter produced chimeric
embryos
Learning About Human Genetics
• A genome is all the DNA in one cell
of an organism
• The Human Genome Project’s goal is to
identify the DNA sequence of every
gene in the human genome
• 20,000 to 25,000 genes
• Finding the exact location and function
of each gene could take decades!
DNA Fingerprinting
• Hair, skin and blood can all be used to
make a DNA fingerprint
• No 2 people have the exact same DNA
• A DNA finger print consists of a series of
bands, something like a bar code.
• DNA finger prints can be used to show
whether people are related, identify people
and solve crimes.
• Humans have only 300 more
genes than what are also found in
mice…
• “This tells me genes can’t
possibly explain all of what
makes us what we are.”
Craig Venter, president of Celera Genomics
(Maryland firm that led one of the mapping
teams for the Human Genome Project)