These authors contributed equally to this work.
The convergent evolution of blue iris pigmentation in primates took distinct molecular paths
Article first published online: 2 MAY 2013
Copyright © 2013 Wiley Periodicals, Inc.
American Journal of Physical Anthropology
Volume 151, Issue 3, pages 398–407, July 2013
How to Cite
Meyer, W. K., Zhang, S., Hayakawa, S., Imai, H. and Przeworski, M. (2013), The convergent evolution of blue iris pigmentation in primates took distinct molecular paths. Am. J. Phys. Anthropol., 151: 398–407. doi: 10.1002/ajpa.22280
- Issue published online: 22 JUN 2013
- Article first published online: 2 MAY 2013
- Manuscript Accepted: 24 MAR 2013
- Manuscript Received: 3 DEC 2012
- Rosalind Franklin Award and NIH. Grant Number: GM72861 (to M.P.)
- University of Chicago Biological Sciences Division Summer Fellowship (to S.Z.) and National Institutes of Health. Grant Number: T32 GM007197 (to W.M.)
- parallel evolution;
How many distinct molecular paths lead to the same phenotype? One approach to this question has been to examine the genetic basis of convergent traits, which likely evolved repeatedly under a shared selective pressure. We investigated the convergent phenotype of blue iris pigmentation, which has arisen independently in four primate lineages: humans, blue-eyed black lemurs, Japanese macaques, and spider monkeys. Characterizing the phenotype across these species, we found that the variation within the blue-eyed subsets of each species occupies strongly overlapping regions of CIE L*a*b* color space. Yet whereas Japanese macaques and humans display continuous variation, the phenotypes of blue-eyed black lemurs and their sister species (whose irises are brown) occupy more clustered subspaces. Variation in an enhancer of OCA2 is primarily responsible for the phenotypic difference between humans with blue and brown irises. In the orthologous region, we found no variant that distinguishes the two lemur species or associates with quantitative phenotypic variation in Japanese macaques. Given the high similarity between the blue iris phenotypes in these species and that in humans, this finding implies that evolution has used different molecular paths to reach the same end. Am J Phys Anthropol 151:398–407, 2013.© 2013 Wiley Periodicals, Inc.