title: Gene expression, chromosome heterogeneity and the fast-X effect in mammals.
abstract: The higher rate of non-synonymous over synonymous substitutions (dN/dS) of the X chromosome compared with autosomes is often interpreted as a consequence of X hemizygosity. However, other factors, such as gene expression, are also known to vary between X and autosomes. Analysing 4800 orthologues in six mammals, we found that gene expression levels, associated with GC content, fully account for the variation in dN/dS between X and autosomes with no detectable effect of hemizygosity. We also report an extensive variance in dN/dS and gene expression between autosomes.
authors.affiliation: Institut des Sciences de l'Evolution, CC64, Université Montpellier II, Place Eugène Bataillon, Montpellier cedex 5 34095, France.
authors.forename: Linh-Phuong
authors.initials: LP
authors.lastname: Nguyen
authors.affiliation: Institut des Sciences de l'Evolution, CC64, Université Montpellier II, Place Eugène Bataillon, Montpellier cedex 5 34095, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Galtier
authors.affiliation: Institut des Sciences de l'Evolution, CC64, Université Montpellier II, Place Eugène Bataillon, Montpellier cedex 5 34095, France benoit.nabholz@univ-montp2.fr.
authors.forename: Benoit
authors.initials: B
authors.lastname: Nabholz
mesh_terms: D000818:Animals; D019143:Evolution, Molecular; D015870:Gene Expression; D057898:Hemizygote; D006801:Humans; D008322:Mammals / Q000235:genetics*; D015999:Multivariate Analysis; D011110:Polymorphism, Genetic; D014960:X Chromosome / Q000235:genetics*
keywords: X chromosome; fast-X; gene expression; hemizygosity; non-synonymous substitutions; synonymous substitutions