This document discusses genetically modified organisms and transgenic animals. It explains that genetic modification involves introducing a foreign gene into an organism using techniques like transfection or transformation. A variety of animal species have been genetically modified, including mice, goats, rabbits, fish, cattle, sheep, and pigs. The objectives of genetic modification can be to improve traits like milk and meat production or to produce proteins encoded by transferred genes. Vectors like retroviruses and adenoviruses are often used to introduce genes into animal host cells.

1. Genetically Modified Organisms - II
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Lecture- 40

2. • Foreign gene is introduced by one or other technique
of transfection or transformation.
• Introduction of DNA segment, either naked or
integrated, into a vector.
• Gene introduced is called a transgene.
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3. Types of
Transfection
Stable
transfection
Transient
transfection
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4. 1970
M. Mandel and A. Higa
developed
a transfection method for E. coli
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5. Objectives of genetic modification
• Majority of gene transfers aims at studies on
promoter function, reporter gene expression,
regulation of gene expression, etc.
• Genetic modification of animals may be aimed at
improving milk, meat, wool production, etc.
• Genes are transferred to obtain a large scale
production of the proteins encoded by these genes.
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6. Animal Vectors
• Animal vectors are based on one or the other
viruses, e.g. SV40 vectors.
• Most of the vectors have the ability to replicate in
suitable animal host cells.
• TYPES:
▫ Retrovirus vectors
▫ Adenovirus vectors
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7. Transgenic animals produced
• Transgenics have been produced in a variety of
animal species
▫ Transgenic mice
▫ Transgenic goat
▫ Transgenic rabbit
▫ Transgenic fish
▫ Transgenic cattle
▫ Transgenic sheep
▫ Transgenic pigs
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8. • 1980 Mouse
• 1983 Tobacco plant
• 1985 Rabbit, sheep and pig
• 1994 Tomato plant (Flavr Savr)
• 1996 Cotton (Bollgard cotton/Bt
cotton)
Transgenic Organisms
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9. Transgenic Mice
• Mice are preferred because they have:
▫ Short oestrous cycle and gestation period
▫ Relatively short generation time
▫ Production of several offsprings per pregnancy
▫ Convenient in vitro fertilization
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10. Transgenic Rabbit
• Quite promising for gene farming or molecular
farming which aims at the production of recoverable
quantities of pharmaceutically or biologically
important proteins encoded by the transgenes
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11. Other animals
Transgenic cattle
• for increased milk and meat production
• molecular farming
• improved properties of casein
• improved lactose and butter fat in milk
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12. Transgenic sheep
• for incresed wool quantity and quality
• for meat production
• as bioreactors
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13. Transgenic pigs
• For increased meat production
• Serve as bioreactors
Transgenic pigs expressing human growth
hormones do show improved growth but have
several health problems due to chronic
overproduction of growth hormones
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14. Pigs
engineered
to develop
Cystic
Fibrosis
2008
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15. Genetic transformation of Drosophila
1982
Allen C. Spradling
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16. Transgenic fish
• For increased growth
• To serve as bioreactors
Gene transfers have been successful in several
fishes like common carp, rainbow trout, Atlantic
salmon, catfish, goldfish.
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