Transcript Genetic engineering

Selective Breeding
and
Natural Selection
DNA Technology
Genetic engineering
is the field of science that deals with
making changes in an organism’s
DNA
DNA extraction
the process of separating DNA from
the rest of the cell
Restriction enzymes
• are used to cut DNA. They are very specific
and cut DNA only in specified places due to a
nucleotide sequence.
Gel electrophoresis
procedure where DNA fragments are placed in a
special gel and an electric current is run through
it. The current picks up the pieces and carries
them through the gel. Bands are then compared
to a known sample. This is used to compare
samples from crime scenes to suspects(looking
for a specific match), or a child to a possible
family or father(looking for similarities in DNA).
CODIS is the genetic “bank” of DNA samples from
crime scenes.
DNA fingerprinting
an analysis of sections of DNA that are
used to identify individuals….such as
criminals, missing children, MIA soldiers,
crime victims, etc. Each person has unique
DNA that can be used for identification.
Suspect 3 has some explaining to do…
Ways to get desired traits
• Selective Breeding
– Inbreeding
– hybridization
• Cloning
• Genetic engineering
Selective breeding
• allowing only those animals or plants with
desired traits to reproduce. This is how we
have developed many varieties of corn, wheat,
rice, cows, horses, dogs, etc. These are
referred to as domesticated varieties.
Selective Breeding
• Selective breeding has been practiced for thousands
of years.
• It involves humans choosing two individuals to mate
to produce offspring with certain desirable
characteristics,
– such as leaner meat on an animal or wheat seeds that
remain attached to the plant for longer.
– Many plants and animals for domestic and agricultural
purposes have been bred in this way to produce new
varieties.
Dogs are a great example
Examples
• Cattle and sheep have been specifically bred
for such things as leaner meat, more milk,
creamier milk, better quality wool and
increased resistance to disease.
• Pigs, due to selective breeding are less
aggressive, have smaller tusks and more meat
compared to their genetically similar
ancestors.
Examples
• Horses have been selectively bred from wild
horses over centuries resulting in many
varieties including draft horses.
– breeds such as the Shire, Clydesdale, Belgian and
Suffolk which are used for specific farming
purposes, but all involve greater strength, size and
ability to pull wagons, ploughs and drays.
– Race horses also originated from wild horses and
have been bred for greater speed.
Forms of selective breeding
1. Inbreeding- involves crossing 2 individuals
that have similar desired traits.
– The offspring will probably have the same traits.
– Increases the chances of the recessive alleles
being inherited
– Lead to genetic disorders
Forms of selective breeding
2. Hybridization- crossing 2 genetically different
individuals (hybrid-different)
- have best traits from both parents
Hybridization
• the crossing of dissimilar organisms to bring
together the best of both organisms.
• Many crops and domesticated animals are
hybrids
Cloning
• Producing offspring with desired traits that are
genetically identical to the parent.
– Cutting from a plant to grow new one
– Dolly, a sheep produced in 1996 was the first
cloned mammal.
http://science.howstuffworks.com/life/genetic/cloni
ng.htm
Cloning
• refers to transferring the genetic material of
one cell into another cell..this can result in
either a group of identical cells or a new
individual, in which case it is called
reproductive cloning. Dolly, a sheep produced
in 1996 was the first cloned mammal.
Make MIMI the Mouse
http://learn.genetics.utah.edu/conte
nt/tech/cloning/clickandclone/
WEDNESDAY
Genetic engineering
is the field of science that deals with
making changes in an organism’s
DNA
Genetic Engineering
• Genes from one organism are transferred into
the DNA of another organism.
– Used in medicines and food crops
– Cows to produce milk that have a blood clotting
protein needed by people with hemophilia.
Recombinant DNA
• the combination of DNA from different
sources. (EX> Human gene for human growth
hormone is inserted into bacteria and then
used to produce growth hormone used to
treat growth disorders). This is the same
procedure used to produce insulin for
diabetics, or clotting factor for hemophiliacs:
they just insert a different gene into the
bacteria.
Genetic
Engineering
G M
• term used to describe genetically modified
foods
Gene therapy
• a process in which an absent or faulty gene is
replaced with a normal working gene. This
has been successfully done in some cases in
humans
Gene therapy
• Using genetic engineering to correct some
genetic disorders in humans.
• Involves inserting copies of a gene directly
into a person’s cells.
– Hemophilia- replaces the defective allele on the X
chromosome to correct the instructions for blood
clotting.
Concerns
• Some feel harmful to environment when used
for crops or cause health problems in human.
Vocabulary
• Selective Breeding: The intentional breeding of organisms with
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desirable traits in an attempt to produce offspring with similar
desirable characteristics or with improved traits.
Species: A group of organisms having common characteristics
that is capable of mating with one another.
Variation: Differences in individual living things from each
other.
gene: A segment of DNA that codes for a particular protein.
gene pool: All the genes of all the members in a population.
• selective pressure: Any environmental factor that favors
one trait over another.
• mutation: A random change in a gene or a group of genes.
• genetic isolation: What occurs when two groups of one
species are prevented from breeding with each other.
• inherited trait: An inherited characteristic—such as hair
and eye color or muscle and bone structure—that has been
passed on from a previous generation.
• acquired trait: An acquired characteristic—such as the
ability to ride a bike or do karate—that is attained
throughout life. Acquired traits are not passed on
genetically.
Change Over Time
FRIDAY
• Adaptation: A change in an organism over time
that helps it to survive and reproduce in its
environment.
• Biodiversity: The variety and complexity of life
on Earth.
• Camouflage: Appearance that is designed for
hiding in the environment.
• Competition: Living things striving for food,
living space, mates, and other resources.
• Evolution: The process whereby new species
arise from earlier species by accumulated
changes. Often referred to as “change over
time.”
• Fitness: The ability of a living thing to survive
and reproduce in its environment.
• Natural Selection: The process by which
individuals in a population inherit genes that
allow them to survive and be reproductively
successful.
• Variation: Differences in individual living
things from each other.
• Scientific theory: well-tested concept or
explanation not proven
• Fossils- preserved remains of animals that
died long ago
Basic Concepts of Natural Selection
• Individual living things are different from each
other. This is called variation.
• Variation is important because without it,
populations cannot evolve over time.
• Living things produce more offspring than can
survive, and many that survive do not
reproduce.
• Living things compete for limited resources,
such as food and shelter.
Natural Selection
• Factors that affect the process:
– Overproduction
– Variation
– Competition
– Selection
– Environmental Change
– Genes and Natural Selection