is there any practical approach on the horizon (or here) that allows scientists to apply crispr throughout all the cells in a living organism? I get how this works with a single cell, but typically that's only useful for either very very very small or very very very young individuals (right?)
No. For permanent genomic changes you have to select what you want. For precise edits, there's usually a counterselection (so it takes two hits). The efficiency of the process is still low. You have to be willing to throw away a lot of cells to get precisely the correct one. One way to think of it is a big component of what CRISPR does is to make it easier to find the good edits (although it does also make good edits more likely).
You don't necessarily need to hit every cell in an organism to produce useful therapies. Most cells aren't going to be expressing the gene that's causing a disease, only cells in the affected tissue or organ need to be treated. In some cases, you may not even need to get all of the affected cells, just repairing a subset could improve outcomes. (1/8 of a functioning pancreas is a lot better than 0/8)
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is there any practical approach on the horizon (or here) that allows scientists to apply crispr throughout all the cells in a living organism? I get how this works with a single cell, but typically that's only useful for either very very very small or very very very young individuals (right?)
No. For permanent genomic changes you have to select what you want. For precise edits, there's usually a counterselection (so it takes two hits). The efficiency of the process is still low. You have to be willing to throw away a lot of cells to get precisely the correct one. One way to think of it is a big component of what CRISPR does is to make it easier to find the good edits (although it does also make good edits more likely).
You don't necessarily need to hit every cell in an organism to produce useful therapies. Most cells aren't going to be expressing the gene that's causing a disease, only cells in the affected tissue or organ need to be treated. In some cases, you may not even need to get all of the affected cells, just repairing a subset could improve outcomes. (1/8 of a functioning pancreas is a lot better than 0/8)