CRISPR/Cas: They worked out a slicker way to modify DNA than the old "Agrobacterium plasmids" GE technique.
The plasmids were like shotguns firing slugs: they took one big, long chunk of DNA (typically including some transgenic DNA) and blasted it or spliced it into the genome SOMEWHERE. Somewhere random, so that it was not coordinated with other DNA and had to include its own promoters and initiators and ... I forget the other genetic elements, like control elements and regulators. Anyway, they often used bacterial DNA for promoters, to make one stretch of DNA produce lots of copies in RNA.
Not that it only ADDS DNA, and adds it to a random location. Typically, they would find one or more genes that they want to ADD, then cross their fingers and try to tack on regulators, start-stop signals or whatever, from whatever species or genetic library they thought might work. Then they would test in the lab and select versions that show promise. Then field trials. Then convince the FDA and consumers that transgenic DNA plus trial-and-error is a good idea.
Expensive, slow and clumsy. But it was better than the prior method, coating hard particles with DNA and then randomly blasdt8ng them into cells with compressed air, hoping that some got into the nucleus!
(I'm skipping over TALEN, which was an intermediate technique that looked great until CRISPR came along and was MUCH better.)
CRISPR is cool in that it EDITS DNA. Instead of scrounging genes from bacteria and what-have-you, splicing them randomly into the genome and hoping, it lets crop breeders look at specific genes already in the crop. Typically they'll have a complete DNA sequence of the variety they are improving, and of many other varieties that have at least some desirable qualities.
(That may be another part of why CRISPR is better than Agrobacterium plasmids. Today, breeders have full DNA sequences available in "libraries" , plus growing knowledge of what many of those genes do, and what sequence changes are needed to change certain properties. Ten or twenty years ago, everyone had much less knowledge like that, and had to use a big hammer to get results.)
CRISPR is more scalpel-like. You identify exactly what DNA base-pairs in what gene you want to change, and then you EDIT exactly that change in exactly that gene. Not add, edit. Not "in some random, uncontrollable location". In base pairs # 12345 through 12399, in gene "Qwerty357".
They can decide that they like or want to test the version of that gene in one variety of (say) corn , so they edit that gene in the variety they are improving. They can edit a gene to exactly match the gene in other varieties.
Or, with more effort, they can even analyze the enzyme involved and try to make it more efficient by trying out NEW versions of the enzyme that they invent themselves, based on computer models of how the modified enzyme might fold and react. (That kind of "enzyme engineering" is so hard that they usually change just 1-2 amino acids at a time, so that their predictions are more likely to give a desirable result. It's much easier to borrow something that works from a sister variety, than to invent something new and then TRY to make it work!
As radical geneticists discovered when they tried to create an "artificial bacterium" from scratch, "forget about it". They just kept failing totally until they decided to START with a living bacterium that nature had created, and then edit it down to the simplest form that still "worked". That soon taught them how little they understand. Under the hood, life is even more complicated than Burbank, Darwin and modern biochemists realized. Sure, we might understand 20-30 volumes about the simpler aspects of molecular biochemistry. But LIFE appears complex enough to need 300 (or maybe 3,000 or 30,000) volumes.
CRISPR is not grafting big blocks of transgenic DNA from bacteria, fish and whatnot into food crops. It's changing just a few amino acids in chosen proteins. There might still be unexpected side effects, but probably hundreds or thousands of times less uncertainty and potential danger, because the change is thousands or tens of thousands times less extensive, and usually comes from the same SPECIES, not from different genuses and even Families.
This is key: they don't need to flounder around with transgenic DNA, hoping that some major change will be an improvement. They could say "we like 'the way the tassel curls' better in corn # ABC-123 than in this ZYZ-789 strain we're improving". Since they often know the 3-5 genes that affect "tassel curl" , they can look for other varieties that curl the way they want, and then try out versions of the genes FROM the varieties with desirable traits, IN the variety they are breeding.
NOW the MOST important part comes into view. Since they have some knowledge of how it works in one variety, they can more nearly predict what it will do in another species. Instead of wandering around through bacteria and fish, hoping that throwing some big cluster of transgenic genes at a problem might help it, they are doing much simpler things, more like merging two versions of a document or tuning an engine than grafting a fish-head onto a chicken.
With CRISPR there is much less trial-and-error, and it lends itself well to using NO transgenic DNA!
In the past, genetic engineering was REALLY slow and expensive. Trial and error, working blind by today's standards. And then the field trials to get FDA approval were where most GMO crops failed, after years of heavy spending. And consumer rejection, widespread in Europe and Japan, and fairly widespread in the USA, kills more crops even AFTER commercial approval.
So first-generation GE was too expensive for NGOs and universities to attempt. Only for-profit Borg like Monsanto could afford to do it, and their R&D was 100% targeted at profit. "Sustainable profit" in the sense that attack-lawyers gave them a total lock on the market that no one could struggle against, whether it starved people in India or not.
But now, with CRISPR, university labs, GMOs and under-funded research groups in developing countries CAN do GE.
Sometimes THEIR goals are alleviation of starvation! Improved nutrition. Ability to grow on marginal land and in too-hot or too-dry climates. Crops for climate change. Combining as many favorable traits as possible into a few NON-transgenic OP varieties, so people could save their own seed again.
I see that as a major improvement.
Downside? Well, Agrobacterium plasmids only worked on plants.
CRISPR works just fine on animals including humans. It's already being used in research, to find actual CURES for serious genetic diseases of humans.
And it could be used to meddle with our genes in other ways. It's more difficult to get those changes into the germ line so they will be passed along to human descendents, but I think there is some progress on that as well. Maybe, some decade, "designer babies". (I really wish that the name of the human species was true, that "Homo sapiens" meant we were wise.)
It IS a Brave New World. As the Firesign Theater said:
"Sure, living in the future is like having a hive of bees in your head. But there they are!"
Or as J'Kar said in Babylon 5:
"The future isn't what it used to be."
