Fig. 4: Odorant receptor (OR) gene family evolution in fungus-growing ants.
From: Relaxed selection underlies genome erosion in socially parasitic ant species
A Gene family tree for attine ant OR genes. The outermost circle shows gene subfamilies, the middle circle highlights OR gene clades with reductions in inquiline social parasites (orange blocks and numbers), and the inner circle highlights OR gene clades that expanded in the leaf-cutting ant species compared to the phylogenetically more basal non-leaf-cutting attine ants (blue blocks; cf. basal branches in Fig. 1). B Reconciled gene tree of OR clade 285 belonging to the 9-exon subfamily that diversified independently and at a particularly high rate in the two leaf-cutting ant genera and subsequently underwent convergent gene losses in all social parasites. Branches with inferred gene deletion events in inquiline social parasites and their hosts are marked in orange diamonds, duplications are marked with circles colored according to the taxonomic affiliation of the ants, and speciation nodes are marked with triangles. Background shading colors highlight the independent expansions in Atta and Acromyrmex.
