TWiEVO 5 letters

Brian writes:

Vincent, Nels,

Really excited by the new podcast, off to a great start. And I really love the tone and style of measured presentation you are both giving the subject. This is something Nels and I discussed briefly at ASV (if you remember, Nels)… that the field of evolution and this ‘modern synthesis’ is very hot and we see more of it within meetings traditionally covering Microbiology, Virology, or Genetics. But there can be an over-eagerness to ascribe to every phenomena we observe a ‘just-so’ adaptation story. No doubt there are some beautiful examples of adaptive evolution that capture something deeply inherent in us – rings some perfect chord regarding our view of life’s ‘grandeur’. But so often things are more messy, more complicated, more drift, more hitchhiking, more non-adaptive processes. Less sexy. It may be dour, but I often remind students and colleagues that the overwhelming story of life in this planet has been unmitigated failure and death. Well over 99%. There is no progression. But it does make those little successes, ourselves included, all the more fascinating and important.

A quick note from something that was said in the preamble to the topic/paper discussions. Vincent noted that RNA recombination also occurs in nature and has been the source of variation in RNA viral populations. This can occur in homologous and non- fashion. Nice examples include the historical diversity generation of Alphaviruses between Old and New world species (Scott Weaver) and intra-serotype recombinants in Dengue. But as an example, Vincent noted Vesicular Stomatitis Virus (VSV). Curious enough, negative-strand viruses appear to undergo very LITTLE recombination (Holmes 2003 J Gen Vir PMID: 13679603). This is actually a big part of why myself and other researchers have used VSV as a good model for experimentally studying virus ‘adaptation’ in the lab without that background. Eddie Holmes has had negative strand RNA virus evolution on his mind as a passion project and has been really digging for more sampling and working out the phylogenetics. His recent look in insects (Li et al 2015 eLife PMID: 25633976) shows this virus genomic strategy is far more diverse than we thought. So how did this diversity come about with low recombination? Again, this goes back to your tone and something said on show: how we teach biology needs to be assessed. Nothing is static. We don’t know everything. But that’s all the more reason why students should be engaged with that wonder and people should want to join this field.

Cheers