This work was supported by KAKENHI (22657026; Grant-in-Aid for Challenging Exploratory Research; Ministry of Education, Culture, Sports, Science and Technology [MEXT], Japan), the Fujiwara Natural History Foundation, and Global COE Program (Center of Excellence for Asian Conservation Ecology as a basis of human–nature mutualism; MEXT, Japan).
Waterfalls drive parallel evolution in a freshwater goby
Article first published online: 1 JUL 2012
© 2012 The Authors. Ecology and Evolution published by Blackwell Publishing Ltd.
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Ecology and Evolution
Volume 2, Issue 8, pages 1805–1817, August 2012
How to Cite
Kano, Y., Nishida, S. and Nakajima, J. (2012), Waterfalls drive parallel evolution in a freshwater goby. Ecology and Evolution, 2: 1805–1817. doi: 10.1002/ece3.295
- Issue published online: 6 AUG 2012
- Article first published online: 1 JUL 2012
- Manuscript Accepted: 15 MAY 2012
- Manuscript Revised: 14 MAY 2012
- Manuscript Received: 1 MAY 2012
- KAKENHI. Grant Number: 22657026
- Fujiwara Natural History Foundation
- Global COE Program
- Allopatric speciation;
- Iriomote Island;
- land erosion;
- landlocked fish;
- Rhinogobius sp. YB;
- Rhinogobius brunneus (Rhinogobius sp. DA)
Waterfalls may affect fish distribution and genetic structure within drainage networks even to the extent of leading evolutionary events. Here, parallel evolution was studied by focusing on waterfall and the landlocked freshwater goby Rhinogobius sp. YB (YB), which evolved from amphidromous R. brunneus (BR). The fish fauna was surveyed at 30 sites in 11 rivers on Iriomote Island, Japan, the geography of which was characterized by terraces/tablelands with many waterfalls. We found that all YB individuals were distributed only above waterfalls (height 6.8–58.7 m), whereas BR, and other fishes, were mostly distributed below waterfalls. Mitochondrial DNA analysis showed that every YB local population above the waterfall was independently evolved from BR. In contrast, cluster analysis of nine morphological characters, such as fin color and body pattern, showed that the morphology of YB individuals held a similarity beyond the genetic divergence, suggesting parallel evolution has occurred relating to their morphology. Genetic distance between each YB local population and BR was significantly correlated with waterfall height (r2 = 0.94), suggesting that the waterfalls have been heightened due to the constant geological erosion and that their height represents the isolation period of YB local populations from BR (ca. 11,000–88,000 years). Each local population of BR was once landlocked in upstream by waterfall formation, consequently evolving to YB in each site. Although the morphology of YB had a high degree of similarity among local populations, finer scale analysis showed that the morphology of YB was significantly correlated with the genetic distance from BR. Consequently, there could be simultaneous multiple phases of allopatric/parallel evolution of the goby due to variations in waterfall height on this small island.