Like I said previously, microRNA is typically highly conserved (have the same sequence) across animals because it’s involved in such important biological processes. But some microRNA isn’t conserved, which makes it particularly interesting. Is it not conserved because it just doesn’t have an important function? Is it not conserved because the divergent microRNA confers a specific fitness benefit to an organism? Or is it a rare mutation that leads to a disease like cancer?

That’s where my particular research comes in. I’m investigating microRNA variation within human populations and across the primate lineage. Here are some examples of interesting trends I may find:

  1. A microRNA is totally conserved across primates and other animals. This microRNA is likely involved in a really important biological process, like making a type of tissue.
  2. A microRNA is totally conserved within primates, but differs from other animals. This microRNA could confer some primate-specific trait.
  3. A microRNA is totally conserved within humans, but differs from other primates. This could be an example of “what makes us human.”
  4. A microRNA is not conserved at all. The more likely explanation is that this isn’t a functional microRNA at all. That’s the risk with working with such new data. Other types of small RNA can be erroneously labeled as a microRNA. MicroRNA is a specific class of small RNA because it’s processed in a very distinct manner and has a specific function.
We already know that there are some differences in microRNA between primates. In 2011, Svante Paabo’s group found a number of microRNA that were upregulated (present in higher amounts) in human brain, but not in chimpanzee brain. When they validated which messenger RNA these microRNA were targeting, they found the targets were involved in neural development. This is an exciting possibility for what shaped human brain evolution, but obviously still needs further testing.
The way my research differs is that I’ll be looking at how the sequence of microRNA differs rather than the amount. A sequence difference could totally change which messenger RNA is targeted, which is what ultimately affects the organism. I’ll be experimentally validating the effects of these sequence changes in a number of primates, including humans.

This is post 7 of 49 of Blogathon. Donate to the Secular Student Alliance here.