Can CRISPR turn a dog into a cat (not at embryo stage)?

[fredreload]

Right I've read all about CRISPR but I can't help to think if such a possibility exists. As far as I know the only way to cause such changes is by modifying cells at the embryo stage. But if crispr can help grow a missing limb or create structural changes at adult stage it does sound like a miracle worker. Anyway, would such a thing be possible, referring to my question at the title, thanks!

P.S. After further study, it seems regeneration is still an ongoing research

 

[Ygggdrasil]

if crispr can help grow a missing limb or create structural changes at adult stage

It cannot do this at the moment.

Most of an organism's body plan is determined during development. In fact, most of the genes specifying the body plan are active only in development and turned off in the adult animal. Therefore, altering these genes in the adult would not cause any substantial changes to the body plan of the organism. In fact, inappropriate activation of genes that regulate development in the adult often leads to cancer.

 

[fredreload]

Well if only gene expression can be controlled, but crispr cannot change gene expression can it? But again, cancer is capable of dividing without any limit, cancer is simply tissue growing out of control, if only it can be correctly regulated then we are one step closer to structural changes, another limb perhaps.

 

[Ygggdrasil]

CRISPR is capable of controlling gene expression in addition to changing the underlying genetic sequence, though use of the CRISPRa/CRISPRi system is probably further away from clinical applications. I'm reluctant to say anything is impossible, but there would be a number of significant hurdles to applying CRISPR to limb regeneration/modification. For example, you would need a much better understanding of limb growth and development than we currently have and you would need tools to control gene expression much more finely than we currently have. It's also not clear to me if the adult body is capable of regenerating limbs (in contrast to organisms like newts which can regenerate limbs as adults).

 

[fredreload]

That leads me to one of the question I have. Different cell type has different gene expression, neuron for brain, skin cell for skin. The thing is something must be controlling how cell express gene expression to take a human shape, skin cell on top of muscle cell on top of bone cell, from how blastocyst divide into a human fetus. I believe it should exist somewhere within the DNA, but so far it is not identified still. I believe this is crucial to the structure we hold, why do we have five fingers but not six. Why is this important? because I believe it has to do with the aging process as well, what controls how cell express gene expression could also control the aging process. It is like a clockwork that slowly unwind itself. The current DNA damage theory just does not seem accurate, we grow old because we are meant to grow old not because we are damaged to become old. It is said that human genome is fully sequenced, I feel that there is still much decoding to do

 

[Ygggdrasil]

It is said that human genome is fully sequenced, I feel that there is still much decoding to do

I agree. Indeed, while ~10% of the human genome is conserved throughout evolution, only about 1% encodes protein. The rest of the conserved but non-protein-coding sequences are thought to encode regulatory sequences that control the expression of the protein-coding genes in space and time. That there is about 10x as much regulatory DNA sequences as protein-coding sequences underlies the importance of these sequences in the biology of multicellular organisms. Understanding how this regulatory DNA works is one of the big challenges facing biology, and we are only beginning to scratch the surface on this topic.

 

[Drakkith]

The current DNA damage theory just does not seem accurate, we grow old because we are meant to grow old not because we are damaged to become old.

Those two ideas (DNA damage and "meant to grow old") are not mutually exclusive in my opinion.

 

[256bits]

I agree. Indeed, while ~10% of the human genome is conserved throughout evolution, only about 1% encodes protein. The rest of the conserved but non-protein-coding sequences are thought to encode regulatory sequences that control the expression of the protein-coding genes in space and time. That there is about 10x as much regulatory DNA sequences as protein-coding sequences underlies the importance of these sequences in the biology of multicellular organisms. Understanding how this regulatory DNA works is one of the big challenges facing biology, and we are only beginning to scratch the surface on this topic.

Is the 1% part of the hormone production and signaling molecules.
https://en.wikipedia.org/wiki/Hormone

Reason I ask, it that
http://www.ks.uiuc.edu/Research/pro_DNA/ster_horm_rec/
the signaling molecules produced by the 1% would be controlling the 10% which in turn controls the 1% in a round-robin manner. Very complicated if I have that right..

 

[Ygggdrasil]

Is the 1% part of the hormone production and signaling molecules.
https://en.wikipedia.org/wiki/Hormone

Reason I ask, it that
http://www.ks.uiuc.edu/Research/pro_DNA/ster_horm_rec/
the signaling molecules produced by the 1% would be controlling the 10% which in turn controls the 1% in a round-robin manner. Very complicated if I have that right..

Yes, most of the regulatory DNA regions rely on proteins in order to function, so you have many different feedback loops operating in a very complicated network.

 

[fredreload]

If only there is a technique to image DNA molecules at real time. With some visualization technique makes DNA decoding simple

 

[fredreload]

I was referring to this. But it's a speculation of year 2030

 

[fredreload]

This seems pretty cool, but regulating cancer would be a hard thing to do at this point. And it's back from 2010

 

[1oldman2]

Here is something a little more current, it will be interesting to see where this tech goes.
http://www.nature.com/news/first-[U...chnologies-wont-lead-designer-babies/']crispr-clinical-trial-gets-green-light-from-us-panel-1.20137?WT.mc_id=SFB_NNEWS_1508_RHBox[/URL]

 

[ProfuselyQuarky]

Here is something a little more current, it will be interesting to see where this tech goes.
http://www.nature.com/news/first-[U...chnologies-wont-lead-designer-babies/']crispr-clinical-trial-gets-green-light-from-us-panel-1.20137?WT.mc_id=SFB_NNEWS_1508_RHBox[/URL]

Oh, very nice, thanks for the link!