mighty mouse

[sheldon]

I saw on the discovery channel that genetisists have injected a mouse with a virus that had a chunk of DNA on it. The DNA was for muscle growth and this mouse was huge and stayed that way. What the heck. That freaked me out. How does this trojen horse style gene injecting thing work? Even if one cell gets infected and changed geneticaly how does the rest of that particuler muscle get changed?

[iansmith]

It is easy, the scientist used a natural process. Some virus can integrate their genome into their host genome (There is trace in most genome sequence to this day). Therefore the gene can be express inside the cell and alter the function of the cell. A possible side effect is that the DNA insert migth be in a gene and can cause some problem.

To get as many cell as you want you use either a large dose of virus (not to large because the immune system could react badly) or you infect some stem cell and reject them or do some cloning with the cell. The scientific probably put a regulator specific for muscle in order for the gene to be express only in muscle.

Viruse have been tested for gene therapy for a while now.

[sheldon]

would the mouses offspring carry the genetic changes made?

[Guybrush Threepwood]

I guess they would pass the canghes to the offspring.
I read once that in the human genome was found some old viral DNA... (any comments are welcome on this)

[iansmith]

Originally posted by sheldon
would the mouses offspring carry the genetic changes made?

I depends when the mouses were transformed and which cell are transformed. If the cell are transformed during their life time, the offspring will not likely carry the modification except if some male gonads cells are transform and not all sperm cell will carry the transformation. For female, most of eggs are produce prior to adulthood. If the mouse are transform prior to cloning, the transformation will carry on by the offsprings (1/4 if the other mate is not transform, 1/2 if both are transgenic). Only One of the chromatids (two chromatids=1 chromosome) will be transform. Therefore one in two sperm/egg cell will have the transformation.

Guybrush Threepwood
I read once that in the human genome was found some old viral DNA... (any comments are welcome on this)

You are rigth and old virus are also found in other living organism too. This is due because some virus that integrate their genome are not really good at it, they make mistake when they remove their genome. Sometime some virus have mutation that cause the enzyme that extract the genome to be off or not to work. So the genome cannot be
cut out anymore.