Chiperoni t1_je515ou wrote

As far as we can tell, you can't fix a misshapen PrP (aka prion). Those "prions" in the paper you are referencing are yeast proteins that have distinct conformations that can propagate like human prions. All humans have tons of PrP but it's rare for one to become a prion. However, once one does it can start a chain reaction.


Chiperoni t1_j9ztjfl wrote

Not in the sense I think you mean. Most physical characteristics are polygenic meaning different combinations of genes are interacting to give off a phenotype. So there's countless other combinations that can yield the same result. Even genes that are linked in all cases like blue eyes can have DNA changes at many different spots. Also outside of nature there is the just as important nurture.


Chiperoni t1_iw61cb4 wrote

To Crispr edit you need two things. One is an enzyme known as Cas. Cas’ job is to cut DNA. The other is a piece of DNA you manufacture. In the simplest terms, one piece of the dna binds Cas and the other binds the DNA of the target. When you combine both parts you create a little homing missile that binds the target so that Cas can make a cut. Now there’s a whole bunch of neat tricks you can do but the simplest are either to make a mutation or add DNA.

Just by having Cas at the target, the DNA will keep getting cut and the cell will repair it. Until it doesn’t because it makes an error. Then because your manufactured DNA doesn’t match the target perfectly it dissociates and Cas stops cutting. Now you have a missense, silent, frameshift, deletion, or nonsense mutation.

Alternatively, while Cas cuts you can also add more DNA that matches the DNA around the target with the hope that when the cell repairs the DNA and that this new DNA sneaks in. Now you have an insertion.

Again lots of little tricks you can do. For example let’s say you want to mutate a protein important in heart muscle. You can literally use CRISPR to insert an artificial gene that is only expressed in the heart by sticking close to a gene sequence that is only expressed in heart. Then you can actually CRISPR in the Cas protein but in a way that it’s only turned on when exposed to a chemical like the chemo drug tamoxifen. So you can grow normal mice and then at whatever point you like expose them to tamoxifen which turns on Cas. This Cas will then only have an effect on your original gene target only in the heart because the artificial DNA sequence you added is only expressed there. Really the possibilities are endless.


Chiperoni t1_iw3xl5a wrote

You might be right that their numbers are stable or increased but if you compare researchers that work on NHP to all other animal models or even just mice, they are a drop in the bucket


Chiperoni t1_iw32elo wrote

Oh definitely feasible. We already do it on human cells and even have done it on human embryos. As long as we have the genome sequenced. I just meant more and more people are stepping away from primate research due to ethics and practicality.


Chiperoni t1_iw2x410 wrote

Almost nobody works with primates anymore and we don’t really do transgenic primates. For lots of animals we do. Mice are the “work horse” for genetic models. Fruit flies, and rats, and zebrafish to some extent too (and yes others). Yes we can breed colonies with specific traits. Then we keep inbreeding them to keep their mutations. That’s like the old school way.

Then came things like the Cre-Lox system. You can use bacteria to make a bunch of DNA with specific sequences that include sites where it can be cut. You can add it to an embryo and have these DNA sequences integrate at specific sites by making the DNA sequence the same as where you want it integrated because every strand of DNA has a complement. You can then cause specific mutations at these sites as an embryo or even in a way you can trigger with chemicals so that the mutation can be triggered at any time at specific tissues. Then you can maintain a colony with inbreeding.

Now the new, new way is to use CRISPR which lets you do this much more consistently with a lot less effort. Then you can inbreed to maintain a colony.