SEMINAR ON

TRANSGENIC ANIMAL

Speaker:

Ananda Kumar Saha

Department of Zoology, R.U.

What is transgenic animal?

A transgenic animal is an animal that has been

genetically engineered to contain one or more extra

genes in its cell. It now has a new, inheritable

property of some type.

Genetically Modified OrganismsGenetically Modified Organisms

Genetically modified organisms are organisms with Genetically modified organisms are organisms with artificially altered DNA.artificially altered DNA.

Created By:Created By:

Adding a foreign geneAdding a foreign geneAltering the base sequence of an existing geneAltering the base sequence of an existing geneDeleting or “ Turning off ” an existing geneDeleting or “ Turning off ” an existing gene

Adding a Foreign GeneAdding a Foreign Gene

Insect resistant plantInsect resistant plant

BioremediationBioremediation

Production of InsulinProduction of Insulin

Vaccine (HBsAg)Vaccine (HBsAg)

Herbicide resistant plantHerbicide resistant plant

AlteringAltering an Existing Gene an Existing Gene

Existing genes in the organism are altered to make Existing genes in the organism are altered to make it produce at higher levels (Growth hormone).it produce at higher levels (Growth hormone).

Deleting/Turning off an Existing GeneDeleting/Turning off an Existing Gene

Deactivating the gene responsible for the ripening Deactivating the gene responsible for the ripening of tomatoes. This new gene can then be inserted of tomatoes. This new gene can then be inserted into tomato DNA to give them a longer shelf life.into tomato DNA to give them a longer shelf life.

Genetically Modified AnimalGenetically Modified Animal

MicroinjectionMicroinjection

Embryonic stem cell transferEmbryonic stem cell transfer

Nuclear TransferNuclear Transfer

MicroinjectionMicroinjection

Eggs are harvested from super-ovulated animals and Eggs are harvested from super-ovulated animals and fertilized fertilized in vitro.in vitro.

Two hundred to three hundred copies of the foreign Two hundred to three hundred copies of the foreign gene are injected into the recently fertilized egg. gene are injected into the recently fertilized egg.

Implanted into surrogate mothers.Implanted into surrogate mothers.

A small proportion of the animals born are transgenic.A small proportion of the animals born are transgenic.

MICROINJECTION PROCESS

Embryonic stem cell transferEmbryonic stem cell transfer

Target gene sequences to specific sites in the Target gene sequences to specific sites in the genomegenome

Alternations made to stem cells in cultureAlternations made to stem cells in culture

Mutated stem cells injected into blastocystMutated stem cells injected into blastocyst

Blastocyst implanted into foster motherBlastocyst implanted into foster mother

Transgenic animals are bornTransgenic animals are born

Embryonic Stem CellEmbryonic Stem Cell

Four Cell Stage

Two Cell Stage

Eight Cell Stage

Early Fertilization stage

Embryonic Stem CellEmbryonic Stem Cell

Blastocyst Fetus (Pluripotent)

Adult

Nuclear TransferNuclear Transfer

Removing the nucleus of an unfertilized egg and replacing it with Removing the nucleus of an unfertilized egg and replacing it with the nucleus of a donar cell (hence containing the complete the nucleus of a donar cell (hence containing the complete genome)genome)

An electric current is used to fuse the nucleus in the cell and An electric current is used to fuse the nucleus in the cell and trigger the egg to begin developingtrigger the egg to begin developing

The reconstructed eggs are then implanted into a surrogate The reconstructed eggs are then implanted into a surrogate mother.mother.

Somatic cells can be cultured, subjected to genetic manipulation Somatic cells can be cultured, subjected to genetic manipulation in vitro and then produce viable animals by means of nuclear in vitro and then produce viable animals by means of nuclear transfer.transfer.

“DOLLY” AND THE TRANSGENIC CLONES

Dolly was born in July 1996 and was introduced in March 1997.

Wilmut and Cambell fused 277 adult mammary gland

cells with 277 egg cells, but they achieved only

thirteen pregnancies, and only one pregnancy

resulted in a live birth. But that one offspring, Dolly.

Scientist and Dolly

A B

A) Ian Wilmut, the Roslin Institute Researcher

B) Dooly, the cloned sheep who had a mother, but no father

TRANSGENIC ANIMAL PRODUCTS

Human Lactoferrin in Cow’s milk.

Lactoferrin a protein found in animal milk that has the ability to bind iron molecule.

The protein has strong antibacterial properties because it removes iron from the environment that bacteria need for growth .It relieves iron-deficiency anemia.

Transgenic GoatTransgenic Goat

Milk contains protein normally found on the Milk contains protein normally found on the surface of the parasite that causes surface of the parasite that causes malariamalaria.. The The protein elicit an antibody response in test protein elicit an antibody response in test animals and could conceivably be used to animals and could conceivably be used to immunize against immunize against malariamalaria..

HUMAN HEMOGLOBIN FROM PIG

Transgenic pig that produces human hemoglobin. Day

old embryos received injections of two genes for

hemoglobin production, and the embryos were then

implanted to surrogate.

Only about five in a thousand injections succeeded, and

only three pigs survived to birth .

Negative Side

Nuclear transfer technology results in high mortalities and low birth rates.

The offspring are abnormally large size, undeveloped lungs, ill health, implantation problem.

Poor placental development are common.

Trangenic Animal

Cloned Kitten Cloned Pigs

Mule Endangered sheeps

Trangenic Animal

Do transgenic animals have any direct benefit to humans?

DNA technologists have been able to produce a transgenic pig

that produces human hemoglobin. Purified hemoglobin from

this animal can one day be used in place of human blood for

transfusions during many surgical procedures.

QUESTIONLINE

Are there any other products possible from transgenic animals?

Research work is currently progressing in methods to

obtain compounds that may be used to treat emphysemea,

cystic fibrosis, and dissolve blood clots.

QUESTIONLINE

How about improving the quality of the animal itself?

Transgenic cows, could one day produce a higher quality milk, one that is similar to human milk.

Chiken and cattle that synthesize antiviral proteins encourage diseases resistance in their bodies. Such animals, would require less antibiotic therapy.

QUESTIONLINE

What are the risks of cloning?What are the risks of cloning?

Reproductive cloning is expensive and highly inefficient.Reproductive cloning is expensive and highly inefficient.

More than 90% of cloning attempts fail to produce More than 90% of cloning attempts fail to produce viable offspring.viable offspring.

More than 100 nuclear transfer procedures could be More than 100 nuclear transfer procedures could be required to produce one viable clone.required to produce one viable clone.

Higher rates of infection, tumour growth, and other Higher rates of infection, tumour growth, and other disorders.disorders.

Japanese studies have shown that cloned mice live in Japanese studies have shown that cloned mice live in poor health and die early.poor health and die early.

Australia’s first cloned sheep appeared healthy and Australia’s first cloned sheep appeared healthy and energetic on the day she died. energetic on the day she died.

Should Humans be Cloned?Should Humans be Cloned?

Due to the inefficiency of animal cloning and Due to the inefficiency of animal cloning and lack of understanding about reproductive lack of understanding about reproductive cloning, many scientist and physicians strongly cloning, many scientist and physicians strongly believe that it would be unethical to attempt to believe that it would be unethical to attempt to clone humans.clone humans.

Several cloned animals have died prematurely Several cloned animals have died prematurely from infectious and other complications.from infectious and other complications.

The attempt to clone humans at this time is The attempt to clone humans at this time is considered potentially dangerous and ethically considered potentially dangerous and ethically irresponsible.irresponsible.

Thank you