Phylogenomic data reveal hard polytomies across the backbone of the large genus Solanum (Solanaceae)

Increased volumes of phylogenomic data have revealed incongruent topologies in gene trees, both between and within genomes across many organisms. Some of these incongruences indicate polytomies that may remain impossible to resolve. Here, widespread gene-tree discordance is uncovered along the backbone of Solanum, one of the largest flowering plant genera that includes the cultivated potato, tomato, and eggplant, as well as 24 minor crop plants. First, a densely sampled species-level phylogeny of Solanum is built using unpublished and publicly available Sanger sequences comprising 60% of all accepted species (742 spp.) and nine regions (ITS, waxy, and seven plastid markers). The robustness of the Sanger-based topology is tested by examining a plastome dataset with 140 species and a nuclear target-capture dataset with 39 species of Solanum. Clear incongruences between species trees generated from the supermatrix, plastome, and nuclear target-capture datasets are revealed. Discordance within the plastome and target-capture dataset are found at different evolutionary depths in three different areas along the backbone of these phylogenetic trees, with polytomy tests suggesting that most of these nodes have short branches and should be collapsed. We argue that incomplete lineage sorting due to rapid diversification is the most likely cause behind these polytomies, and that embracing the uncertainty that underlies them is crucial to depict the evolution of large and rapidly radiating lineages.

Vector mesons in medium

After decades-long attempts to measure the mass shift and understand the origin of hadron mass, it became clear that one has to analyze hadrons with small vacuum width. Also, to identify the effect of chiral symmetry breaking, one has to start by looking at chiral partners. Such considerations inevitably points to studying K∗ and K1 in matter. The masses of both particles can potentially be measured from nuclear target based experiments and/or heavy ion collisions. Once the masses and mass difference of K∗ and K1 mesons are measured, we will be closer to understanding the origin of hadron mass and the effects of chiral symmetry breaking. We will review the topic using the operator product expansion (OPE) perspective.

8B and hep solar neutrino detection by terrestrial experiments

Solar neutrino spectra of 8B and hep neutrinos produced by pp-chain reactions are analysed for various nuclear detectors in current terrestrial experiments. The well known folding method is applied by employing appropriately simulated solar neutrino distributions and using recently calculated total cross section of neutrino- nucleus processes. We focus on the nuclear target of current experiments like MOON and ICARUS as well to other promising nuclear isotopes.