Centrohelida is still searching for a phylogenetic home: analyses of seven Raphidiophrys contractilis genes

摘要: By recent advance in evolutionary biology, the majority of eukaryotes are classified into six eukaryotic assemblages called as "supergroups". However, several groups show no clear affinity to any supergroups. Centrohelida, one major heliozoan groups, such an unresolved lineage. In this study, we newly determined genes encoding translation elongation factor 2 (EF2), cytosolic heat shock protein 70 (HSP70), and 90 (HSP90) from centroheliozoan Raphidiophrys contractilis. The three were then combined with previously actin, alpha-tubulin, beta-tubulin, SSU rRNA sequences phylogenetically analyze position Centrohelida global phylogeny. Although multi-gene data sets examined study largest ones including sequences, relationships between considered unresolved. Our careful investigation revealed that phylogenetic estimates highly sensitive included alignment. signal alpha-tubulin appeared conflict another: former strongly prefers a monophyly Diplomonadida (e.g., Giardia), Parabasalia Trichomonas), Heterolobosea Naegleria), Euglenozoa Trypanosoma), while latter unites Diplomonadida, Parabasalia, Metazoa, Fungi. addition, EF2 robustly Rhodophyta Viridiplantae, remaining do not positively support particular relationship. Thus, it is difficult identify relatives present since strong (and some conflicting) gene-specific "signals" predominant current data. We concluded larger scale phylogenies necessary elucidate origin evolution Centrohelida.