Inactivation dates of the human and guinea pig vitamin C genes
The capacity to biosynthesize ascorbic acid has been lost in a number of species including primates, guinea pigs, teleost fishes, bats, and birds. This inability results from mutations in the GLO gene coding for L-gulono-γ-lactone oxidase, the enzyme responsible for catalyzing the last step in the vitamin C biosynthetic pathway. We analyzed available primate and rodent GLO gene sequences to determine their evolutionary history. We used a method based on sequence comparisons of lineages with and without functional GLO genes to calculate inactivation dates of 61 and 14 MYA for the primate and guinea pig genes, respectively. These estimates are consistent with previous phylogeny-based estimates. An analysis of transposable element distribution in the primate and rodent GLO sequences did not reveal conclusive evidence that illegitimate recombination between repeats has contributed to the loss of exons in the primate and guinea pig genes.
KeywordsVitamin C L-gulono-γ-lactone oxidase GLO gene Unitary pseudogene Human Guinea pig
We thank the two anonymous referees for their useful and constructive comments on a previous version of this manuscript. This work was supported by a Discovery Grant from the Natural Science and Engineering Research Council of Canada to G. D.
- Cooper DN (1999) Human gene evolution. BIOS Scientific, OxfordGoogle Scholar
- Graur D, Li W-H (2000) Fundamentals of molecular evolution, 2nd edn. Sinauer Associates, Inc., Sunderland, MassachusettsGoogle Scholar
- Krasnov A, Reinisalo M, Pitkanen TI, Nishikimi M, Molsa H (1998) Expression of rat gene for L-gulono-gamma-lactone oxidase, the key enzyme of L-ascorbic acid biosynthesis, in guinea pig cells and in teleost fish rainbow trout (Oncorthynchus mykiss). Biochim Biophys Acta 1381:241–248PubMedGoogle Scholar
- Toyohara H, Nakata T, Touhata K, Hashimoto H, Kinoshita M, Sakaguchi M, Nishikimi M, Yagi K, Wakamatsu Y, Ozato K (1996) Transgenic expression of L-gulono-gamma-lactone oxidase in medaka (Oryzias latipes), a teleost fish that lacks this enzyme necessary for L-ascorbic acid biosynthesis. Biochem Biophys Res Commun 223:650–653CrossRefPubMedGoogle Scholar
- Uddin RK, Zhang Y, Siu VM, Fan Y, O’Reilly RL, Rao J, Singh SM (2006) Breakpoint associated with a novel 2.3 mb deletion in the VCFS region of 22q11 and the role of Alu (SINE) in recurring microdeletions. BMC Med Genet 7:18Google Scholar
- Winter H, Langbein L, Krawczak M, Cooper DN, Jave-Suarez LF, Rogers MA, Praetzel S, Heidt PJ, Schweizer J (2001) Human type I hair keratin pseudogene phihHaA has functional orthologs in the chimpanzee and gorilla: evidence for recent inactivation of the human gene after the Pan-Homo divergence. Hum Genet 108:37–42CrossRefPubMedGoogle Scholar