It’s been an eventual two weeks in evolutionary biology. Meanwhile, I’ve somehow kept a lab-field course on track with minimal in person engagement, planned a bit for actual fieldwork in a couple weeks from now, and started wrangling a couple hundred freshly sequenced genomes.
And I managed to take notes on a little reading, too:
Roy et al. 2022 Convergent evolution of a blood-red nectar pigment in vertebrate-pollinated flowers. PNAS doi: 10.1073/pnas.2114420119
- Dissects the biochemical basis of pollinator-attracting red coloration in the nectar of Nesocodon mauritianus, pollinated primarily by Phelsuma geckoes.
- The same pigment chemistry is found in the nectar of hummingbird-pollinated Jaltomata herrarae, which is in a totally different subclade of the Asterids.
Lai and Schötterer. 2022. Evolution of phenotypic variance in response to a novel hot environment. Molecular Ecology doi: 10.1111/mec.16274
Experimentally evolved two populations of Drosophila simulans in a high-temperature environment for 100 generations, compared variance in males’ gene expression before and after adaptation.
- Vast majority of genes showed no change in expression variance; somewhat more had decreased variance than had increased.
- In both replicate populations, genes with decreased variance were all expressed in the midgut. Genes with increased variance were expressed in different tissues in the two populations.
- Because somewhat different sets of genes showed reduced expression variance in the two populations, the authors suggest they’ve found evidence of genetic redundancy in the phenotype under selection, which makes sense.
- Authors hypothesize that reduced environmental complexity (food variety?) in the lab narrows the fitness landscape and creates strong stabilizing selection on the midgut.