Lower statistical support with larger datasets: insights from the Ochrophyta radiation

摘要: It is commonly assumed that increasing the number of characters has potential to resolving radiations. We studied photosynthetic stramenopiles (Ochrophyta) using alignments heterogeneous size and origin (6,762 sites for mitochondrion, 21,692 plastid 209,105 nucleus). While statistical support relationships between six major Ochrophyta lineages increases when comparing mitochondrion trees, it decreases in nuclear tree. Statistical not simply related dataset but also quantity phylogenetic signal available at each position our ability extract it. Here, we show proper extraction difficult attain, as demonstrated by conflicting results obtained varying taxon sampling. Even though use a better fitting model improved reduced observed conflicts, provided higher ochrophyte radiation than larger nucleus dataset. propose tree due an acceleration evolutionary rate one short deep internal branch, implying more per resolve Our work therefore suggests that, order radiations, beyond obvious datasets with positions, need continue developing models sequence evolution design methods search genes/characters contain specifically branches.