Xanthine dehydrogenase (Xdh): Episodic evolution of a "neutral" protein
- Author(s): Rodríguez-Trelles, F
- Tarrío, R
- Ayala, FJ
- et al.
Published Web Locationhttps://doi.org/10.1007/s002390010239
We investigated the evolution of xanthine dehydrogenase (Xdh) in 34 species from the three multicellular kingdoms, including one plant, two fungi, and three animal phyla, two classes of vertebrates, four orders of mammals, and two orders of insects. We adopted a model-based maximum-likelihood framework of inference. After accounting for among-site rate variation and heterogeneous nucleotide composition of the sequences using the discrete gamma distribution, and using nonhomogeneous nonstationary representations of the substitution process, the rate of amino acid replacement is 30.4 × 10-10/site/year when Drosophila species are compared but only ≈18 × 10-10/site/year when comparisons are made between mammal orders, between insect orders, or between different animal phyla and ≈11 × 10-10/site/year when comparisons are made between birds and mammals, between fungi, or between the three multicellular kingdoms. To account for these observations, the rate of amino acid replacement must have been eight or more times higher in some lineages and at some times than in others. Spastic evolution of Xdh appears to be related to the particularities of the genomes in which the locus is embedded.
Many UC-authored scholarly publications are freely available on this site because of the UC Academic Senate's Open Access Policy. Let us know how this access is important for you.