I'm having problems trying to understand how RNA interference works.

From what I understood, in simple terms there is this dsRNA which is fragmented into siRNA by the enzyme called Dicer, and those siRNA make the RISC complex active, which leads to the degradation of mRNA which are complementary to one of the strands of the original dsRNA.

Said this (which I don't even know if it is correct), how this relates to the petunias experiment? From what I understood the researchers put into the petunias an enzyme that coded for the pigment and not strands of dsRNA which then would have created the inhibition...

What am I missing?

PS. I don't have technical knowledge about Technologies so excuse me in case I said wrong things.

Thanks in advance everyone.

  • $\begingroup$ Can you please provide a citation for the "petunias experiment"? $\endgroup$
    – MattDMo
    Jun 25, 2016 at 22:20
  • $\begingroup$ By Andrew Fire and Craig C. Mello - For the petunias pigments. $\endgroup$
    – Nur Bedeir
    Jun 26, 2016 at 19:37

1 Answer 1


They introduced a foreign gene responsible for petunia leaf colour, with the intentions of up-regulating gene expression for this colour, which was purple. What was observed however was intriguing. Rather than an up-regulation of the purple colour, the leaves were all white instead. This finding showed that the RNAi system in plants recognised the foreign gene and degraded it. Not only that, but the RNAi system also identified the endogenous equivalent of the foreign gene and down-regulated this also thinking it was foreign. This is how they discovered this miraculous finding :)

  • $\begingroup$ Hi Chris - on this site when you answer a question you need to include some background information and references to back up the claims you make in your answer. Without this important information your post will potentially be voted down and you will lose reputation points or deleted altogether. Looking forward to see your edits - thanks for your contribution. $\endgroup$ Nov 17, 2016 at 13:22

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