Post on 20-Aug-2019
Transgenic animals
• For what reason?• How to do it...• Can you clone an animal?• How can you use it?
Transgenic animalsWhy?
• Selective breeding is performed since centuries.
• Breeding is time consuming.• Crossing in properties is time consuming.• Only a limited number of properties
available.
• Introduction of a desired property(hypothesis driven; without hypothesis)
• Fast generation of animal lines carrying the desired property
• Animal model for human diseases• Animal system to produce biomolecules
(„Pharming“)• Xeno-Transplantates
Transgenic animalsFor what reason?
• Efficient mechanism of transgene integration • Transfer of genes < 8 kb possible• random insertion of the transgene• Retroviral contamination of the transgenic
animal
Transgenesis in MiceRetroviral Vector
Transgenese in MäusenMikroinjektion
• Low efficient mechanism of transgeneintegration (5-10%)
• Transfer of large genes possible• random insertion of the transgene• Variable expression levels
no selection of the transgene necessary
Black mouse -no ES cell integration
Chimeric mouse -high ES cell integration
Chimäre Mäuse
Chimeric mouse -low ES cell integration
• Efficient transfection• positive-negative Selection • Targeted insertion of the gene• Characterization before animal
generation• Time and cost intensive
Transgenesis in MiceStem cell Method
1 2 3
lacZ-tagged insertion allele
FRTFRT
loxPloxPβgalneo
lacZ-tagged null allele (Δ exon)
1 βgal 3FRTFRT
loxP
Cre recombinase
βgalneo
pre-conditional allele (wild-type)
1 2 3
null allele (Δ exon, frameshift, NMD)
Flp recombinase
1 3
Cre recombinase
Transgenesis in Mice“Smart“ recombination Methods
“Knock-in” mouse model fornephrogenic Diabetes insipidus
loxP loxPE242X
K.O.
WildtypeK.O.
Exon 1 Intron 1 Exon 2 NeoR Exon 3/3’-UTR
„Gene“
• 1997, first living bovine offspring derived from a stem cell of a 30 days-old fetus
• Difference compared to Dolly?
„Cc:“• First clone cat
• Derived from fibroblast cell by nucleus transfer.
• Coat color differs between the genetic mother and the offspring
Commercialized pet cloning
• available: Cryoconservation of cellscosts: $895 - $1395
• Texas A&M takes $250,000 for cloning a cat