New paper by Chris on dental gene loss in xenarthrans published in Peer Community Journal
Updated: Oct 25
Chris' work on the evolution and loss of function of dental genes across the xenarthran radiation has been published in Peer Community Journal (doi:10.24072/pcjournal.303) after being recommended by Peer Community in Genomics through a fully transparent and particularly useful and efficient peer-review process. We are proud to support this new open science alternative to classical scientific publishing after signing the PCI manifesto.
In this work, taking advantage of genomic data generated within the ConvergeAnt project for several xenarthran species, we studied the molecular evolution of 11 core dental genes in most living species of Xenarthra, characterizing shared inactivating mutations and patterns of relaxed selection during their radiation. We found evidence of independent and distinct events of dental gene loss in the major xenarthran subclades. First, we found strong evidence of complete enamel loss in the common ancestor of sloths and anteaters, suggested by the inactivation of five enamel-associated genes (AMELX, AMTN, MMP20, ENAM, ACP4). Next, whereas dental regression appears to have halted in sloths, presumably a critical event that ultimately permitted adaptation to an herbivorous lifestyle, anteaters continued losing genes on the path towards complete tooth loss. Echoes of this event are recorded in the genomes of all living anteaters, being marked by a 2-bp deletion in a gene critical for dentinogenesis (DSPP) and a putative shared 1-bp insertion in a gene linked to tooth retention (ODAPH). By contrast, in the two major armadillo clades, genes pertaining to the dento-gingival junction and amelogenesis appear to have been independently inactivated prior to losing all or some enamel. These genomic data provide evidence for multiple pathways and rates of anatomical regression, and underscore the utility of using pseudogenes to reconstruct evolutionary history when fossils are sparse.
This paper was also supported by a collaborative grant from the France-Berkeley Fund with Michael Nachman (Museum of Vertebrate Zoology, University of California, Berkeley, USA) and benefited from sequence capture experiments conducted in Hendrik Poinar's lab (McMaster Ancient DNA Centre, McMaster University, ON, Canada).
Emerling C.A., Gibb G.C., Tilak M.-K., Hughes J.J., Kuch M., Duggan A.T., Poinar H.N., Nachman M.W. & Delsuc F. (2023). Genomic data suggest parallel dental vestigialization within the xenarthran radiation. Peer Community Journal 3:e75. doi:10.24072/pcjournal.303
Peer Community in Genomics recommendation by Didier Casane:
Science News article by Elizabeth Pennisi: