Transgenic pharming

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Transgenic pharming

• Goats that produce tPA (breaks up clots)
• Sheep that produce alpha-1 antitrypsin (AAT) only
  in mammary tissues
• Lack of AAT increases risk of developing
  emphysema
• Sheep that produce factor VIII, required for
  loting clotting in Hemophilia A patients

2
Other transgenic pharming products

• Cows
• Lactoferrin
• Added to infant formula to bind iron and prevent
  bacterial infection
• Pigs
• Hemoglobin
• Acts as a blood substitute
• Rabbits
• Erythropoietin
• Treats anemia from dialysis
• Rats
• Human growth hormone
• Treats pituitary dwarfism

3
Difficulties in trasgenic pharming

• Difficulty in getting genes integrated, expressed
  properly with no side effects
• One example (sheep with AAT)
• 152 surrogates were implanted
• gave birth to 112 lambs
• Only 1 male, 4 females had transgene
• Only one female gave birth to a transgenic
  offspring

4
Animal cloning

• embryo splitting
• Egg is fertilized in vitro and allowed to develop
  to 8-16 cell stage
• Cells are then separated and each is grown to
  form genetically identical embryos
• Embryos are then transplanted into surrogate moms
• Basically an extension of the way identical twins
  or triplets are produced naturally
• cell fusion
• Used to produce large numbers of genetically
  identical embryos
• nuclear transfer
• Donor eggs and door nuclei are fused

5
Cell fusion

• Uses unfertilized eggs from which the nucleus has
  been removed
• A fertilized embryo is split into single cells
• Embryo cells and enucleated eggs are fused, each
  then containing an identical nucleus
• Eggs are implanted in surrogate mothers
• Genetically identical calves are born

6
Cloned sheep

• Difference with Dolly- the nucleus used to create
  her came from an adult cell (not embryonic)- the
  udder
• Overturned previously held thought that adult
  cells/nuclei would be unable to direct
  development

7
Dolly and her surrogate mother