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METHODS FOR PRODUCTION OF TRANSGENIC ANIMALS - Coggle Diagram
METHODS FOR PRODUCTION OF TRANSGENIC ANIMALS
Definition of Transgenic animals
Animal that have had a foreign gene deliberately inserted into their genome
DNA microinjection
INTRODUCTION
(This method involves the direct microinjection of a chosen gene construct (a single gene or a combination of genes) from another member of the same species or from a different species, into the pronucleus of a fertilized ovum)
RANDOM PROCESS
(The insertion of DNA is, however, a random process, and there is a high probability that the introduced gene will not insert itself into a site on the host DNA that will permit its expression).
PROCESSING
(The manipulated fertilized ovum is transferred into the oviduct of a recipient female, or foster mother that has been induced to act as a recipient by mating with a vasectomized male).
GENE EXPRESSION
(The introduced DNA may lead to the over- or under-expression of certain genes or to the expression of genes entirely new to the animal species)
ADVANTAGE
(A major advantage of this method is its applicability to a wide variety of species).
Embryonic stem cell mediated gene transfer
INTRODUCTION
(This method involves prior insertion of the desired DNA sequence by homologous recombination into an in vitro culture of embryonic stem (ES) cells).
DIFFERENTIATION
( Stem cells are undifferentiated cells that have the potential to differentiate into any type of cell (somatic and germ cells) and therefore to give rise to a complete organism).
RESULT
(These cells are then incorporated into an embryo at the blastocyst stage of development. The result is a chimeric animal).
KNOCK-OUTMETHOD
(ES cell-mediated gene transfer is the method of choice for gene inactivation, the so-called knock-out method).
IMPORTANCE AND ADVANTAGE
(This technique is of particular importance for the study of the genetic control of developmental processes. This technique works particularly well in mice. It has the advantage of allowing precise targeting of defined mutations in the gene via homologous recombination).
Retrovirus-mediated gene transfer
INTRODUCTION
(To increase the probability of expression, gene transfer is mediated by means of a carrier or vector, generally a virus or a plasmid).
DEFINITION
(Retroviruses are commonly used as vectors to transfer genetic material into the cell, taking advantage of their ability to infect host cells in this way)
EXPLANATION
(Offspring derived from this method are chimeric, i.e., not all cells carry the retrovirus. Transmission of the transgene is possible only if the retrovirus integrates into some of the germ cells).
SUCCESS RATE
(For any of these techniques the success rate in terms of live birth of animals containing the transgene is extremely low).