Mosaic and concerted evolution in the visual system of birds
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Date
2014
Authors
Gutierrez-Ibanez, Cristian I.
Iwaniuk, Andrew N.
Moore, Bret A.
Fernandez-Juricic, Esteban
Corfield, Jeremy R.
Krilow, Justin M.
Kolominsky, Jeffrey
Wylie, Douglas R.
Journal Title
Journal ISSN
Volume Title
Publisher
Public Library of Science
Abstract
Two main models have been proposed to explain how the relative size of neural structures varies through evolution. In the
mosaic evolution model, individual brain structures vary in size independently of each other, whereas in the concerted
evolution model developmental constraints result in different parts of the brain varying in size in a coordinated manner.
Several studies have shown variation of the relative size of individual nuclei in the vertebrate brain, but it is currently not
known if nuclei belonging to the same functional pathway vary independently of each other or in a concerted manner. The
visual system of birds offers an ideal opportunity to specifically test which of the two models apply to an entire sensory
pathway. Here, we examine the relative size of 9 different visual nuclei across 98 species of birds. This includes data on
interspecific variation in the cytoarchitecture and relative size of the isthmal nuclei, which has not been previously reported.
We also use a combination of statistical analyses, phylogenetically corrected principal component analysis and evolutionary
rates of change on the absolute and relative size of the nine nuclei, to test if visual nuclei evolved in a concerted or mosaic
manner. Our results strongly indicate a combination of mosaic and concerted evolution (in the relative size of nine nuclei)
within the avian visual system. Specifically, the relative size of the isthmal nuclei and parts of the tectofugal pathway covary
across species in a concerted fashion, whereas the relative volume of the other visual nuclei measured vary independently
of one another, such as that predicted by the mosaic model. Our results suggest the covariation of different neural
structures depends not only on the functional connectivity of each nucleus, but also on the diversity of afferents and
efferents of each nucleus.
Description
Sherpa Romeo green journal: open access
Keywords
Avian visual system , Visual system of birds , Mosaic evolution model , Concerted evolution model , Visual nuclei , Isthmal nuclei
Citation
Gutierrez-Ibanez, C. I., Iwaniuk, A. N., Moore, B. A., Fernandez-Juricic, E., Corfield, J. R., Krilow, J. M., ... & Wylie, D. R. (2014). Mosaic and concerted evolution in the visual system of birds. PLoS ONE, 9(3), e90102. doi:10.1371/journal.pone.0090102