Gene expression, chromosome heterogeneity and the fast-X effect in mammals

Linh-Phuong Nguyen (1) , Nicolas Galtier (1) , Benoit Nabholz (1)

1 UMR ISEM - Institut des Sciences de l'Evolution de Montpellier

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.

Mots clés: X chromosome; non-synonymous substitutions; synonymous substitutions; fast-X; hemizygosity; gene expression

Domaines: Evolution [q-bio.PE]

Linh-Phuong Nguyen, Nicolas Galtier, Benoit Nabholz. Gene expression, chromosome heterogeneity and the fast-X effect in mammals. Biology Letters, 2015, 11 (2), pp.20150010 - 20150010. ⟨10.1098/rsbl.2015.0010⟩. ⟨hal-01815517⟩