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PLoS One. 2017 Dec 20;12(12):e0189349. doi: 10.1371/journal.pone.0189349. eCollection 2017.

Multifactorial genetic divergence processes drive the onset of speciation in an Amazonian fish.

Author information

1
Department of Genetics and Evolution, University of Geneva, Geneva, Switzerland.
2
Department of Marine Sciences, Universidade Federal de São Paulo, Campus Baixada Santista, Santos/SP, Brazil.
3
Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, Switzerland.
4
Department of Biology, Universidade Federal de Rondônia, Porto Velho/RO, Brazil.

Abstract

Understanding the processes that drive population genetic divergence in the Amazon is challenging because of the vast scale, the environmental richness and the outstanding biodiversity of the region. We addressed this issue by determining the genetic structure of the widespread Amazonian common sardine fish Triportheus albus (Characidae). We then examined the influence, on this species, of all previously proposed population-structuring factors, including isolation-by-distance, isolation-by-barrier (the Teotônio Falls) and isolation-by-environment using variables that describe floodplain and water characteristics. The population genetics analyses revealed an unusually strong structure with three geographical groups: Negro/Tapajós rivers, Lower Madeira/Central Amazon, and Upper Madeira. Distance-based redundancy analyses showed that the optimal model for explaining the extreme genetic structure contains all proposed structuring factors and accounts for up to 70% of the genetic structure. We further quantified the contribution of each factor via a variance-partitioning analysis. Our results demonstrate that multiple factors, often proposed as individual drivers of population divergence, have acted in conjunction to divide T. albus into three genetic lineages. Because the conjunction of multiple long-standing population-structuring processes may lead to population reproductive isolation, that is, the onset of speciation, we suggest that the multifactorial population-structuring processes highlighted in this study could account for the high speciation rate characterising the Amazon Basin.

PMID:
29261722
PMCID:
PMC5738069
DOI:
10.1371/journal.pone.0189349
[Indexed for MEDLINE]
Free PMC Article

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