A new technology from Monsanto et al

[prairiegardens]

Started to read a posting about a new technology involving RNA that Monsanto has got permission to use in corn.  The little I read was just enough to get me so depressed  I couldn't deal with taking the time to really understand it, it all seems like  some sort of nightmare, mad scientists intent on reshaping life. Anyone know anything about this stuff? 

[billw]

Probably RNA interference (RNAi). The gist of it is that you put a substance into the cell that binds to messenger RNA and prevents it from be used to produce a protein. This can be done without modifying the organism, for example as a pesticide spray, or it can be done be adding or modifying a gene in order to produce the substance that binds the mRNA. A good example of that was the old Flavr Savr tomato where they inserted a gene that blocked production of a ripening enzyme. In practice, it really isn't much different than conventional genetic engineering when it comes to plant breeding; you still need to add or alter genes to produce the RNAi.

[philagardener]

Another recent technology is called CRISPR. CRISPR has only been used for a few years, whereas RNAi has been around for decades.

CRISPR uses a complex of a bacterial protein, called a nuclease, and a guide RNA to cut genomic DNA at a specific sequence that matches the guide. This protein/RNA complex can be introduced directly into cells (in this approach, no foreign genes are added, although the technology can be implemented in a variety of ways).

When cells repair the broken DNA, the ends join imprecisely, resulting in small deletions and other changes in the gene. These are indistinguishable at the sequence level from naturally occurring mutations (that can result from natural breaks in DNA). However, because CRISPR targets genes by design, rather than chance, it is a very efficient way to generate mutations in specific genes of interest rather than screening very large populations for naturally-occurring mutations.

To the plant geneticist, the difference is like having a laser scalpel vs. trying to find a needle in a haystack.