The problem: Genomic datasets, especially from next-gen sequencing, are often full of holes (missing genotypes). We can "impute" or infer this missing information, which is crucial for downstream analyses like GWAS. This process dramatically increases statistical power.

Take-home: convergent form does not guarantee genetic interchangeability. In heterogeneous landscapes, parallel solutions can be reproductively incompatible when combined.

Interpretation: divergent selection drives Dune–Headland barriers; heterogeneous Headlands plus polygenic adaptation yield alternative genetic solutions that sometimes clash.

Predictions: as φ decreases (environments diverge), the probability of incompatibilities rises; and as the number of interacting loci grows, incompatibilities accumulate faster. This provides one continuum linking ecological and mutation-order speciation.

Theory: we extend Unckless–Orr with (i) an environmental symmetry parameter φ (how similarly selection acts across sites) and (ii) polygenic architectures with interacting loci.

Field transplant reanalysis: in Dunes, non-locals perform much like locals (aligned selection). In Headlands, locals outperform non-locals (fine-scale heterogeneity). Together, these patterns explain compatibility in Dunes and idiosyncratic barriers among Headlands.

Mutation-order signal: some Headland × Headland crosses between distant regions show intrinsic barriers despite shared prostrate form—consistent with different genetic routes to similar phenotypes.

First check—history: using a multilocus phylogeny (framed by prior genomic work), we confirm repeated evolution of ecotypes rather than a single split-and-spread.

System: coastal Senecio lautus with repeated “Dune” (erect) and “Headland” (prostrate) ecotypes along Australia’s coast. Multiple parapatric pairs let us test selection’s role with natural replication.

We’ve just published a paper on Senecio showing that ecological speciation and mutation-order speciation can act together rather than as an either/or. Congratulations, Maddie James and MC Melo!

Excited to share our newly submitted preprint on Senecio speciation led by Maddie E. James and Maria C. Melo. www.biorxiv.org/content/10.1...

Bluesky seems refreshingly calm and interesting. Love the bundles to follow groups of people. Still on X for following science not, hopefully yet, here. I repost and comment on interesting science. I am an evolutionary geneticist, but have very broad interests. See you around! #evolution #senecio