LINEAGE-SPECIFIC VARIATION IN SLOW- AND FAST-X EVOLUTION IN PRIMATES
Article first published online: 2 FEB 2012
© 2012 The Author(s). Evolution © 2012 The Society for the Study of Evolution.
Volume 66, Issue 6, pages 1751–1761, June 2012
How to Cite
Xu, K., Oh, S., Park, T., Presgraves, D. C. and Yi, S. V. (2012), LINEAGE-SPECIFIC VARIATION IN SLOW- AND FAST-X EVOLUTION IN PRIMATES. Evolution, 66: 1751–1761. doi: 10.1111/j.1558-5646.2011.01556.x
- Issue published online: 1 JUN 2012
- Article first published online: 2 FEB 2012
- Accepted manuscript online: 29 DEC 2011 01:30PM EST
- Received August 23, 2011, Accepted December 4, 2011
- Male mutation bias;
- effective population size;
- mating system;
- life history traits;
- adaptive evolution
Theories predict that the evolutionary rates of X-linked regions can differ from those of autosomal regions. The male-biased mutation theory predicts a slower rate of neutral substitution on the X chromosome (slow-X evolution), as the X spends less time in male germlines, where more mutations originate per generation than in female germlines. The fast-X theory, however, predicts a faster rate of adaptive substitution on the X chromosome when newly arising beneficial mutations are, on average, partially recessive (fast-X evolution), as the X enjoys a greater efficacy of positive selection. The slow- and fast-X processes are expected to interact as the degree of male-biased mutation can in turn influence the relative rate of adaptive evolution on the X. Here, we investigate lineage-specific variation in, and the interaction of, slow- and fast-X processes using genomic data from four primates. We find consistent evidence for slow-X evolution in all lineages. In contrast, evidence for fast-X evolution exists in only a subset of lineages. In particular, the marmoset lineage, which shows the strongest evidence of fast-X, exhibits the lowest male mutation bias. We discuss the possible interaction between slow- and fast-X evolution and other factors that influence the degrees of slow- and fast-X evolution.