http://www.nature.com/nrm/journal/v9/n9/pdf/nrm2472.pdf
“MicroRNAs (miRNAs) are known to regulate gene expression at the level of translation, but how does this affect what proteins are produced? Two recent papers have shown that individual miRNAs can affect the expression of hundreds of proteins.
One known as miR-223 seems to function as a rheostat to finely adjust protein output.
Another miRNA let-7b is can fine-tune protein production from thousands of genes.
Individual miRNAs can have an effect on global protein expression, and protein repression is likely to be mediated by a specific complementary sequence target region in the corresponding messenger RNA. The emerging picture is that miRNAs do not have just a small number of mRNA targets — they function at the transcriptional and translational level to subtly modulate what specific proteins are produced.”
Do the exact complimentary target sequences for these miRNAs being present on many mRNAs coding for different proteins, mean that all these sequences and proteins have a common ancestor, or were the target sequences derived independently?
The study of miRNAs and their target mRNAs and proteins may be good ID research, as I suspect that many unrelated proteins are controlled by the same miRNA. Because the target sequence is the same, that seems to imply strongly that design, rather than descent with modification, was involved.