Rapid divergence of a gamete recognition gene promoted macroevolution of Eutheria.

Autor: Roberts EK; Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA.; Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, USA., Tardif S; Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, USA.; Reproductive Biology Division, JangoBio, Fitchburg, WI, USA., Wright EA; Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA., Platt RN 2nd; Host-Pathogen Interaction Program, Texas Biomedical Research Institute, San Antonio, TX, USA., Bradley RD; Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA.; Natural Science Research Laboratory, Museum of Texas Tech University, Lubbock, TX, USA., Hardy DM; Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, USA. daniel.hardy@ttuhsc.edu.
Jazyk: angličtina
Zdroj: Genome biology [Genome Biol] 2022 Jul 11; Vol. 23 (1), pp. 155. Date of Electronic Publication: 2022 Jul 11.
DOI: 10.1186/s13059-022-02721-y
Abstrakt: Background: Speciation genes contribute disproportionately to species divergence, but few examples exist, especially in vertebrates. Here we test whether Zan, which encodes the sperm acrosomal protein zonadhesin that mediates species-specific adhesion to the egg's zona pellucida, is a speciation gene in placental mammals.
Results: Genomic ontogeny reveals that Zan arose by repurposing of a stem vertebrate gene that was lost in multiple lineages but retained in Eutheria on acquiring a function in egg recognition. A 112-species Zan sequence phylogeny, representing 17 of 19 placental Orders, resolves all species into monophyletic groups corresponding to recognized Orders and Suborders, with <5% unsupported nodes. Three other rapidly evolving germ cell genes (Adam2, Zp2, and Prm1), a paralogous somatic cell gene (TectA), and a mitochondrial gene commonly used for phylogenetic analyses (Cytb) all yield trees with poorer resolution than the Zan tree and inferior topologies relative to a widely accepted mammalian supertree. Zan divergence by intense positive selection produces dramatic species differences in the protein's properties, with ordinal divergence rates generally reflecting species richness of placental Orders consistent with expectations for a speciation gene that acts across a wide range of taxa. Furthermore, Zan's combined phylogenetic utility and divergence exceeds those of all other genes known to have evolved in Eutheria by positive selection, including the only other mammalian speciation gene, Prdm9.
Conclusions: Species-specific egg recognition conferred by Zan's functional divergence served as a mode of prezygotic reproductive isolation that promoted the extraordinary adaptive radiation and success of Eutheria.
(© 2022. The Author(s).)
Databáze: MEDLINE
Externí odkaz: