Outgroup, alignment and modelling improvements indicate that two TNFSF13-like genes existed in the vertebrate ancestor

• DOI: 10.1007/s00251-016-0967-1
• Publication Date: 2017-01-09T16:10:31Z
• Authors: Anthony K . Redmond; Rita Pettinello; Helen Dooley
• Keywords: Lineage (genetic)

The molecular machinery required for lymphocyte development and differentiation appears to have emerged concomitantly with distinct B- T-like subsets in the ancestor of all vertebrates. TNFSF superfamily (TNFSF) members BAFF (TNFSF13/Blys) APRIL (TNFSF13) are key regulators B cell survival, activation mammals, but temporal emergence these molecules, their precise relationship newly identified gene BALM (BAFF APRIL-like molecule), not yet been elucidated. Here, resolve early evolutionary history this family, we improved outgroup sampling alignment quality, applied better fitting substitution models compared past studies. Our analyses reveal that is a definitive TNFSF13 family member, which split from gnathostome (jawed vertebrate) ancestor. Most importantly, however, show both lineages existed ancestors extant This implies has lost, or be found, cyclostomes (jawless vertebrates). results suggest lineage-specific duplication loss events caused regulation, despite shared origins, become secondarily between gnathostomes cyclostomes. Finally, structure lamprey BAFF-like, its phylogenetic placement as sister BALM, more slowly evolving APRIL, indicates primordial regulator was than BAFF-like.