Structurally Aligned rRNA Sequences and Weevil Phylogeny

MARVALDI A.E.

Encuentro; 2016 International Weevil Meeting; 2016

Adriana Marvaldi presented a talk on structural alignment of sequences of the ribosomal markers18S (complete), 28S (D2 and D3), and 16S (IV and V) performed for phylogenetic analysis of weevils.She constructed an annotated alignment for about 270 weevils plus 30 outgroup taxa using as referencethe structural model of rRNA as currently predicted for Arthropoda, including beetles [122,123].A well-resolved tree was produced, but resolution was least in Curculionidae, especially in the CCCMS (Curculioninae, Conoderinae, Cossoninae, Molytinae, Scolytinae) clade. Addition of the protein-coding mitochondrial cytochrome oxidase I (COI) gene improved resolution. The main higher-level relationships found involve: the paraphyly of Nemonychidae, whereby the bulk ofincluded taxa formed a basal weevil clade but part was resolved as closer to Anthribidae: (Nemonyx (Urodontinae (Anthribinae))); the monophyly of Belidae and Attelabidae as well as of their tworespective subfamilies; and the placement of Caridae as sister group of the clade Brentidae +Curculionidae. The main relationships in Curculionidae worth mentioning were: non-monophyly (forming a basal grade) of Brachycerinae (incl. Erirhininae); Dryophthorinae and Platypodinae were sister taxa; recovery of a clade of ?higher? curculionids (with a pedal type of male aedeagus) divided into two sister clades, the CEGH clade (Cyclominae, Entiminae, and allies) and the CCCMS clade. She proposed that it could be helpful to develop a matrix or resource of annotated secondary structural alignments to be available for updates and for use as a template for further phylogenetic analyses of weevils or beetles. Through discussion, Bjarte said that he pursued something similar for 28S (D2?D3) in scolytines but did not find it of great use in providing much more resolution. Duane commented that he and collaborators did this for 28S, 18S, and 16S in Curculionoidea but ultimately decided notto publish the results because they did not noticeably improve resolution in the resulting phylogeny.Adriana insisted that it is still worth the effort to align by structure because it uses a biological criterion to objectively identify homologous positions within length-heterogeneous alignments and to recognize regions of ambiguous alignment.