We show that despite this large mutational influx, rapidly evolving pop'ns naturally cluster into a smaller # of distinct “ecotypes”, even when their genetic diversity is much larger. This non-eq analogue of competitive exclusion is driven by a dynamical priority effect that favors resident strains.

Many studies have found that w/in-species dN/dS decays w/ the genetic distance between strains, which is often attributed to natural selection. Here Zhiru shows that a large portion of this trend can be quantitatively explained by the accumulation of horizontally transferred DNA segments over time.

Finally, thanks to all my collaborators & to the reviewers for their kind feedback that improved our manuscript!

Dominance reversals have long been hypothesized to help keep large-effect loci polymorphic under changing environments. Our results, further strengthened by laboratory measurements, offer some of the first empirical evidence. Read more in the November @natecoevo.nature.com issue:

At the same time, rapid growth under pesticide implies that dominance cannot be too low when alleles confer a fitness advantage. These observations are consistent with contextual dominance: alleles appear recessive when deleterious but dominant when beneficial.

These two independent measurements allowed us to estimate both the cost and dominance of pesticide resistance: decline in exposed cages after pesticide removal requires a fitness cost, while persistence at low frequency in unexposed cages suggests low dominance.

Simultaneously inferring both parameters is generally difficult, especially for deleterious alleles. In our experiment, however, costly resistant alleles remained low in unexposed cages; in exposed cages, they rose in frequency with pesticide application and began to decline once it was removed.

So excited for you and your group! Congrats!

Unfortunately not, but happy to chat offline!

Here we show that within-cell competition is key to plasmid evolution. Look at this photo of plasmids competing inside cells in a colony!!!

This allowed us to visualize the pattern of clones in the tumor! 10/16

Project scientist in computational population genetics (post PhD/postdoc experience usually expected). recruit.apo.ucla.edu/JPF10171