Genetic Engineering

A. Selective BreedingSelective Breeding- allowing only those animals with desired traits to produce the next generation. (domestic animals: horses, cats, farm animals, crop plants)

IV. Genetic Engineering

1. HybridizationHybridization- crossing dissimilar individuals to bring together the best of both organisms. (e.g. disease resistance and food-producing capacity)

Hereford, bred for meat production

2.2. InbreedingInbreeding- continued breeding of individuals with similar characteristics. Can create serious problems (bringing together 2 recessive alleles)

Purpose- to maintain or intensify desirable

traits

Risk- passing of genetic defects

Inbreeding in small ponds of gardens and parks as well as larger rural ponds due to increasingly limited environments, criss-crossed with roads and other barriers. Individuals from less diverse urban populations had a lower survival rate and showed more abnormalities during development, suggesting that inbreeding had exposed harmful mutations which reduced fitness.

B. Increasing Variation

1. Can increase variation by inducing mutations (using radiation or chemicals)

These “oil-eating” bacteria were produced by treating the bacteria with chemicals and radiation, thus inducing a mutation. Hundreds of other useful bacterial strains have been produced this way.

2. Many mutations are harmful. A few can be beneficial

3. Inducing mutations can increase genetic variation.

C. Manipulating DNA

1. Scientist use knowledge of DNA to change DNA molecules

2. Techniques used to extract DNA, cut into smaller pieces and identify base sequences, make unlimited copies of DNA

3. Genetic engineeringGenetic engineering- making changes to DNA code and putting back into cell (by injection into cell, by bacteria, viruses)

Steps:• A. DNA extraction- cells are opened and

DNA is separated from the other cell parts.

• B. Cutting DNA- cut into small fragment by restriction enzymes (cut DNA at a specific sequence of nucleotides).

• C. Separating DNA – method is gel electrophoresis

• Steps:

• 1. A mixture of DNA fragments is place at one end of a porous gel

• 2. Electricity is applied to the gel.

• 3. DNA molecules, which are negatively charged, move toward the positive end of the gel

• 4. Smaller DNA fragments move faster and farther.

• 5. Based on size the DNA fragments make a pattern of bands on the gel that can be compared with other samples.

DNA plus restriction enzyme

Mixture of DNA fragments

Gel

Power source

Longer fragments

Shorter fragments

Section 13-2

Figure 13-6 Gel Electrophoresis

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II. Applications of Genetic Engineering

A. Transgenic organismsTransgenic organisms- bacteria, plants, and animals that contains genes from other organisms

1. Transgenic microorganismsTransgenic microorganisms- bacteria used to produce many important substances for health and industry (e.g. transformed bacteria now make insulin, growth hormone, clotting factor cheaply and in great abundance)

Transgenic tobacco plant- glows in the dark. Produced by transferring a gene from a firefly into a tobacco plant

2. Transgenic AnimalsTransgenic Animals- faster growing animals, resistance to disease, etc.

A transgenic pig with higher levels of growth hormone produced the meatier pork chop.

3. Transgenic PlantsTransgenic Plants- important part of our food supply. (52% of soybeans and 25% of corn are transgenic) resistant to disease, produce their own insecticide, resist weed-killing chemicals, increase vitamin content

Transgenic tomato plants containing genes for viral resistance and healthier than those without the resistant genes (right)

Frost-damaged citrus trees. Plans for the release of genetically engineered bacteria hope to reduce frost damage

B. CloningCloning- a member of a population of genetically identical cells produced from a single cell

The adult sheep is Dolly, the first mammal cloned from an adult cell. The lamb is Dolly’s offspring, called Bonnie.

• Steps:1. Donor cell taken

2. Nucleus of egg cell is removed

3. Donor cell is fused with egg cell

4. Fused cell begins to divide and become an embryo

5. Embryo is placed in a foster mother’s uterus

6. Embryo develops normally and is born

1. May find wide use in medical and scientific research

2. Raises serious ethical issues

• A. Cloning Vector- a carrier that is used to clone a gene and transfer it from one organism to another.

• B. Donor gene- specific gene from another organism spliced into a plasmid, that replicates as the bacteria divide– 1. A plasmid is a circular DNA molecule found

in bacteria.

C. Gene Clone- exact copy of a gene

• D. Steps in getting DNA for cloning1. Cleaving DNA- cutting DNA into fragments using

restriction enzymes

a. Restriction enzymes recognize and bind to specific short sequences of DNA and cut it at a specific site within the sequence.

b. It is not cut straight and creates single stranded DNA pieces with “sticky ends”

c. Sticky ends of DNA pair back up and heal the break or pair with any other fragment cut by the same enzyme.

• 2. Producing Recombinant DNA- it is inserted into a plasmid and allowed to infect the target cells (vector)

• 3. Cloning target cells- target cells are allowed to grow and reproduce

• 4. Screening target cells- target cells that have received the particular gene are isolated

Recognition sequences

DNA sequence

Restriction enzyme EcoRI cuts the DNA into fragments.

Sticky end

Section 13-2

Restriction Enzymes

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III. Plant Cloning• A. Ti Plasmid- used as a vector to carry

genes into plants.– 1. caused by large tumors in plants– 2. tumor gene removed and space filled by

desired gene– 3. Cannot be used in plants that produce cereal

grains

Human Cell

Gene for human growth hormone

Recombinant DNA

Gene for human growth hormone

Sticky ends

DNA recombination DNA

insertion

Bacterial Cell

Plasmid

Bacterial chromosome

Bacterial cell for containing gene for human growth hormone

Figure 13-9 Making Recombinant DNA

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IV. Human Genome ProjectA. Was stated in the late 1980’s, as an

international effort to determine the nucleotide sequence and location of every gene on each chromosome.

B. Completed in April 2003.

Chapter 13 Genetic Engineering

Which of the following have been produced by selective breeding?

a. horse breeds

b. cat breeds

c. dog breeds

d. all of the above

Which of the following have been produced by selective breeding?

a. horse breeds

b. cat breeds

c. dog breeds

d. all of the above

Selective breeding produces

a. more offspring.

b. fewer offspring.

c. desired traits in offspring.

d. transgenic organisms.

Selective breeding produces

a. more offspring.

b. fewer offspring.

c. desired traits in offspring.

d. transgenic organisms.

Which of the following is most likely to bring together two recessive alleles for a genetic defect?

a. inbreeding

b. hybridization

c. genetic engineering

d. transformation

Which of the following is most likely to bring together two recessive alleles for a genetic defect?

a. inbreeding

b. hybridization

c. genetic engineering

d. transformation

The crossing of buffalo and cattle to produce beefalo is an example of

a. inbreeding.

b. hybridization.

c. genetic engineering.

d. transformation.

The crossing of buffalo and cattle to produce beefalo is an example of

a. inbreeding.

b. hybridization.

c. genetic engineering.

d. transformation.

Scientists produced oil-eating bacteria by

a. making bacteria polyploid.

b. inbreeding bacteria.

c. inducing mutations in bacteria.

d. hybridizing bacteria.

Scientists produced oil-eating bacteria by

a. making bacteria polyploid.

b. inbreeding bacteria.

c. inducing mutations in bacteria.

d. hybridizing bacteria.

What is the ultimate source of genetic variability?

a. inbreeding

b. radiation

c. hybridization

d. mutations

What is the ultimate source of genetic variability?

a. inbreeding

b. radiation

c. hybridization

d. mutations

Breeders induce mutations in organisms to

a. increase diversity in populations.

b. make organisms more alike.

c. avoid selective breeding.

d. produce organisms with undesirable characteristics.

Breeders induce mutations in organisms to

a. increase diversity in populations.

b. make organisms more alike.

c. avoid selective breeding.

d. produce organisms with undesirable characteristics.

One function of gel electrophoresis is to

a. separate DNA fragments.

b. cut DNA.

c. recombine DNA.

d. extract DNA.

One function of gel electrophoresis is to

a. separate DNA fragments.

b. cut DNA.

c. recombine DNA.

d. extract DNA.

The process of making changes in the DNA code of living organisms is called

a. selective breeding.

b. genetic engineering.

c. inbreeding.

d. hybridization.

The process of making changes in the DNA code of living organisms is called

a. selective breeding.

b. genetic engineering.

c. inbreeding.

d. hybridization.

Genetic engineering involves

a. reading a DNA sequence.

b. editing a DNA sequence.

c. reinserting DNA into living organisms.

d. all of the above

Genetic engineering involves

a. reading a DNA sequence.

b. editing a DNA sequence.

c. reinserting DNA into living organisms.

d. all of the above

What kind of techniques do scientists use to make transgenic organisms?

a. hybridization

b. inbreeding

c. inducing of mutations

d. genetic engineering

What kind of techniques do scientists use to make transgenic organisms?

a. hybridization

b. inbreeding

c. inducing of mutations

d. genetic engineering

What is an advantage of using transgenic bacteria to produce human proteins?

a. The human proteins produced by transgenic bacteria work better than those produced by humans.

b. Transgenic bacteria can produce human proteins in large amounts.

c. The human proteins produced by transgenic bacteria last longer than those produced by humans.

d. Transgenic bacteria can produce human proteins used to make plastics.

What is an advantage of using transgenic bacteria to produce human proteins?

a. The human proteins produced by transgenic bacteria work better than those produced by humans.

b. Transgenic bacteria can produce human proteins in large amounts.

c. The human proteins produced by transgenic bacteria last longer than those produced by humans.

d. Transgenic bacteria can produce human proteins used to make plastics.

What has been an advantage of producing transgenic plants?

a. increasing the food supply

b. using more pesticides

c. producing clones

d. studying human genes

What has been an advantage of producing transgenic plants?

a. increasing the food supply

b. using more pesticides

c. producing clones

d. studying human genes

The Scottish scientist Ian Wilmut cloned a

a. bacterium.

b. sheep.

c. plant.

d. cow.

The Scottish scientist Ian Wilmut cloned a

a. bacterium.

b. sheep.

c. plant.

d. cow.

Why is Dolly a clone?

a. The source of her DNA was a single body cell.

b. The DNA molecules in all her cells are identical.

c. She was produced using the DNA from an adult’s egg cell.

d. She is genetically identical to her offspring.

Why is Dolly a clone?

a. The source of her DNA was a single body cell.

b. The DNA molecules in all her cells are identical.

c. She was produced using the DNA from an adult’s egg cell.

d. She is genetically identical to her offspring.

Humans use selective breeding to pass desired _________________________ on to the next generation of organisms.

Traits

Characteristics

____________________ is the technique of selective breeding that has led to deformities in certain dog breeds.

Inbreeding

To produce a fruit that has some characteristics of an orange and some of a grapefruit, you would use the selective breeding technique of _________________________.

hybridization

Scientists use radiation and chemicals to induce ____________________.

mutations

DNA samples taken from Dolly and the sheep that donated the body cell would show ____________________ patterns of bands on an electrophoresis gel.

Identical

The same