CloningPart 1

Learning Objectives• To learn about asexual reproduction.

• To learn how cloning produced genetically identical copies of organisms.

• To learn how cows can be cloned.

• To learn how cloning was used to make Dolly the sheep.

Success Criteria• I can state examples of both natural and

artificial clones.

• I understand the difference between identical and non-identical twins.

• I can explain the steps involved in nuclear transfer.

• I can state the benefits and risks involved with cloning.

Cat’s have 10 lives?: Starter• In the USA, there is a company called BioArts

International, which offers a pet cloning service.• A woman from Texas paid $50,000 to clone her cat,

which had died at the age of 17.

Little Nicky, is a genetic clone of Nicky.

He was made by taking the DNA of the original cat and transferring it into the egg cell of another cat.

What reasons can you think of for cloning organisms?

Starter• Twins are natural clones.

• What features of identical twins will be exactly the same?

• What features of identical twins will be different and may be shaped by life experiences?

MAKING COPIES

Making Copies

• The process of cloning is used to make copies of animals and plants.

• The copies are called clones.• Clones are genetically identical to their parents, as

they have the same DNA.

• Cloning is an example of ASEXUAL REPRODUCTION.

Bacteria dividing asexually

Artificial clones made by scientists

Natural clones – identical twins

Natural Clones

• Identical twins share the same genes, so can be thought of as clones.

A single embryo split in to two smaller embryos in the womb.

Each embryo develops in to a separate baby, that have the

same DNA as each other.

Non-identical twins form from two separate egg cells.

Why do non-identical twins not look exactly the same?

• Cloning is an example of ___________________ reproduction.

• Cloning produces genetically ___________________ copies called clones.

• Dolly was the first mammal cloned from an __________________.

• Naturally occurring clones are called _____________.

Finish the sentences about cloning.Choose words from the list.

adult asexual cow identicalsexual similar sisters twins

Importance of Cloning

• Cloning can produce large numbers of animals with desired characteristics.

• Scientists also want to clone pigs to supply organs for human transplants.

• Cloned bacteria already provide us with insulin.

Dairy farmers could clone cows that

produce lots of milk.

Or lots of meat

Importance of Cloning

• Some human diseases can be treated using stem cells obtained from embryos.

• Scientists want to clone human embryos in order to have a good supply of stem cells.

• Some people feel this is unethical though, because:An embryo is a living thing.

Scientists may one day clone adult humans.

Answer Questions 5, 6 & 7 on page 41

Answers:5 – produce lots of animals/plants with desired characteristics.

6 – To provide organs for human transplants.

7 – Feel it is unethical because embryos are living things.

Making Dolly• Dolly the sheep was the

first mammal to be cloned from an adult.

• She was an exact copy of an already living sheep.

• Making her involved taking a body cell from a sheep, removing the nucleus, and then transferring it to an egg cell.

• This is called NUCLEAR TRANSFER.

Complete Worksheet 2 –‘Uses of Cloning’.

• Answers:A. Cloning an animal by taking the nucleus of one of its

cells and transferring it to an egg cell of another animal. Then transplanting that egg into a surrogate mother.

B. Producing lots of animals with desired features, producing stem cells, cloning pets, treating disease.

C. Ethical issues such as ‘playing god’, possibility of cloning humans, embryos are living things.

HIGHER

More on Dolly

• Remember that Dolly didn’t have two parents.• Her DNA came from one adult sheep.

Study Figure 4 on page 41 to see why.Then draw the fully labelled diagram in your

book.

After completing the diagram, explain why Dolly was not related to the sheep that gave birth to

her.She was a surrogate mother who had the egg

transplanted into her uterus.

Risks Involved in Cloning

• The rate of success with nuclear transfer is low.• Dolly was successfully born on the 257th attempt.

• Research into human cloning raises many moral and ethical issues about creating life and then using it to help others.

• Embryos used for stem cells would die in order to help somebody.

• Dolly died of conditions linked to old age.• Her DNA was already ‘6 years old’. Scientists think this

is the reason she died at only age 7.

Answer Questions 8, 9 & 10 on page 41

Answers:8 – The sheep that gave birth to her was an unrelated surrogate.

9 – Any valid reason.

10 – Read out passage.

PLENARY

Plenary

Cloned animals can be used to supply organs for humans.

Do you agree this should happen?

Discuss with your partner, give reasons for your answers.

Write them in your book.

Learning Objectives• To learn about asexual reproduction.

• To learn how cloning produced genetically identical copies of organisms.

• To learn how cows can be cloned.

• To learn how cloning was used to make Dolly the sheep.

Success Criteria• I can state examples of both natural and

artificial clones.

• I understand the difference between identical and non-identical twins.

• I can explain the steps involved in nuclear transfer.

• I can state the benefits and risks involved with cloning.