SEMINAR ON TRANSGENIC ANIMAL Speaker Ananda Kumar Saha

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 Organisms Genetically modified organisms are organisms with artificially altered DNA. Created By: v. Adding a foreign gene v. Altering the base sequence of an existing gene v. Deleting or “ Turning off ” an existing gene

Adding a Foreign Gene n Insect resistant plant n Bioremediation n Production of Insulin n Vaccine (HBs. Ag) n Herbicide resistant plant

Altering an Existing Gene Existing genes in the organism are altered to make it produce at higher levels (Growth hormone). Deleting/Turning off an Existing Gene Deactivating the gene responsible for the ripening of tomatoes. This new gene can then be inserted into tomato DNA to give

Genetically Modified Animal n Microinjection n Embryonic stem cell transfer n Nuclear Transfer

Microinjection n Eggs are harvested from super-ovulated animals and fertilized in vitro. n Two hundred to three hundred copies of the foreign gene are injected into the recently fertilized egg. n Implanted into surrogate mothers. n A small proportion of the animals born are transgenic.

MICROINJECTION PROCESS

Embryonic stem cell transfer n Target gene sequences to specific sites in the genome n Alternations made to stem cells in culture n Mutated stem cells injected into blastocyst n Blastocyst implanted into foster mother n Transgenic animals are born

Embryonic Stem Cell Early Fertilization stage Eight Cell Stage Two Cell Stage Four Cell Stage

Embryonic Stem Cell Blastocyst Fetus (Pluripotent) Adult

Nuclear Transfer n Removing the nucleus of an unfertilized egg and replacing it with the nucleus of a donar cell (hence containing the complete genome) n An electric current is used to fuse the nucleus in the cell and trigger the egg to begin developing n The reconstructed eggs are then implanted into a surrogate mother. n Somatic cells can be cultured, subjected to genetic manipulation in vitro and then produce viable animals by means of nuclear 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) Dolly, 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 Goat Milk contains protein normally found on the surface of the parasite that causes malaria. The protein elicit an antibody response in test animals and could conceivably be used to immunize against malaria.

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 Ø Nuclear transfer technology results in high mortalities and low birth rates. Ø The offspring are abnormally large size, undeveloped lungs, ill health, implantation problem. Ø Poor placental development are common.

Trangenic Animal Cloned Kitten Cloned Pigs

Trangenic Animal Mule Endangered sheeps

QUESTIONLINE 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? Ø Transgenic cows, could one day produce a higher quality milk, one that is similar to human milk. Ø Chiken and cattle that synthesize antiviral proteins encourage diseases resistance in their bodies. Such animals, would require less antibiotic therapy.

What are the risks of cloning? n Reproductive cloning is expensive and highly inefficient. n More than 90% of cloning attempts fail to produce viable offspring. n More than 100 nuclear transfer procedures could be required to produce one viable clone. n Higher rates of infection, tumour growth, and other disorders. n Australia’s first cloned sheep appeared healthy and energetic on the day she died.

Should Humans be Cloned? n Due to the inefficiency of animal cloning and lack of understanding about reproductive cloning, many scientist and physicians strongly believe that it would be unethical to attempt to clone humans. n Several cloned animals have died prematurely from infectious and other complications. n The attempt to clone humans at this time is considered potentially dangerous and ethically irresponsible.

Thank you