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Detection of Transgenic Animals
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Other than the method has been described:

I found, there are methods which has been used for making transgenic animal and there are special techniques to identify them. Making of genetically engineered animals by pronuclear injection or retroviral delivery systems has been a successful approach for generating animal models to better understand the functionality of genes. In transgenic animals created by embryo microinjection, the site of integration of the transgene within the genome is a random event. Thus, when multiple embryos have been injected or infected with the same DNA, the integration site will be different in each founder animal. When the integration events have occurred at the one-cell stage, they should exhibit germline transmission with the potential to be inherited by the founder's offspring. If the integration occurs at a later stage, the resulting mosaic founder may or may not exhibit germline transmission of the transgene. In the case of pronuclear injection, there is typically one insertion site, although multiple transgene copies are often found in a tandem array at that integration site.

Lentivirus transgenesis is becoming an increasingly attractive alternative to pronuclear injection because it is more efficient in terms of successful transgene incorporation into the host genome, less invasive to the embryo, and technically less demanding to perform. Lentiviral delivery systems have been used successfully to generate transgenic mice, rats, pigs, and cattle. The disadvantage of lentivirus is that there are often multiple integration events with random transgene insertions on several chromosomes. Independent of the method of transgene delivery, the insertion site can have profound effects on transgene expression. This can lead to phenotypic effects in the transgenic animal that are not due to the transgene per se, but are a consequence of the integration site, a phenomenon referred to as position effect. It is critical to correlate phenotype with genotype, particularly in animals created via lentivirus transgenesis, since not all copies of the transgene may be contributing equally to the phenotype.

Determining transgene integration sites is challenging. A number of PCR-based methods, often referred to as chromosome walking techniques, have been developed to isolate DNA fragments adjacent to known sequences, including inverse PCR, ligation-mediated PCR (LMPCR), randomly primed PCR (RP-PCR), and T-linker PCR. The method I have mentioned gives several elements of these techniques in a unique way that allows the capture of DNA fragments containing the chromosomal region flanking the transgene. These methods enables quick and inexpensive determination of multiple independent transgene integration sites in founder animals and their offspring.
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Messages In This Thread
Detection of Transgenic Animals - by ashwathi - 11-16-2012, 05:25 PM
RE: Detection of Transgenic Animals - by brijnbhatt - 01-08-2014, 05:10 AM



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