Contrasting GC-content dynamics across 33 mammalian genomes: Relationship with life-history traits and chromosome sizes
- * Corresponding author; email: galtier{at}univ-montp2.fr
Abstract
The origin, evolution and functional relevance of genomic variations in GC-content is a long-debated topic, especially in mammals. Most of the existing literature, however, has focused on a small number of model species and/or limited sequence datasets. We analyzed more than 1000 orthologous genes in 33 fully-sequenced mammalian genomes, reconstructed their ancestral isochore organization in the maximum likelihood framework, and explored the evolution of third-codon position GC-content in representatives of 16 orders and 27 families. We showed that the previously-reported erosion of GC-rich isochores is not a general trend. Several species (e.g. shrew, microbat, tenrec, rabbit) have independently undergone a marked increase in GC-content, with a widening gap between the GC-poorest and GC-richest classes of genes. The intensively studied apes and (especially) murids do not reflect the general placental pattern. We correlated GC-content evolution with species life-history traits and cytology. Significant effects of body mass and genome size were detected, with each being consistent with the GC-biased gene conversion model.
Footnotes
- Received December 18, 2009.
- Accepted May 19, 2010.
- Copyright © 2010, Cold Spring Harbor Laboratory Press
