First evidence for postzygotic reproductive isolation between two populations of Eurasian perch (Perca fluviatilis L.) within Lake Constance

Jasminca Behrmann-Godel,Gabriele Gerlach

doi:10.1186/1742-9994-5-3

Abstract

BackgroundThe evolution of reproductive traits, such as hybrid incompatibility (postzygotic isolation) and species recognition (prezygotic isolation), have shown their key role in speciation. Theoretical modeling has recently predicted that close linkage between genes controlling pre- and postzygotic reproductive isolation could accelerate the conditions for speciation. Postzygotic isolation could develop during the sympatric speciation process contributing to the divergence of populations. Using hybrid fitness as a measure of postzygotic reproductive isolation, we empirically studied population divergence in perch (Perca fluviatilis L.) from two genetically divergent populations within a lake.ResultsDuring spawning time of perch we artificially created parental offspring and F1 hybrids of the two populations and studied fertilization rate and hatching success under laboratory conditions. The combined fitness measure (product of fertilization rate and hatching success) of F1 hybrids was significantly reduced compared to offspring from within population crosses.ConclusionOur results suggest intrinsic genetic incompatibility between the two populations and indicate that population divergence between two populations of perch inhabiting the same lake may indeed be promoted by postzygotic isolation.

Highlights

IntroductionThe evolution of reproductive traits, such as hybrid incompatibility (postzygotic isolation) and species recognition (prezygotic isolation), have shown their key role in speciation
The evolution of reproductive traits, such as hybrid incompatibility and species recognition, have shown their key role in speciation
Our results suggest intrinsic genetic incompatibility between the two populations and indicate that population divergence between two populations of perch inhabiting the same lake may be promoted by postzygotic isolation

Summary

Introduction

The evolution of reproductive traits, such as hybrid incompatibility (postzygotic isolation) and species recognition (prezygotic isolation), have shown their key role in speciation. Theoretical modeling has recently predicted that close linkage between genes controlling pre- and postzygotic reproductive isolation could accelerate the conditions for speciation. To investigate mechanisms of premating isolation under sympatric conditions, Servedio [21] modeled increased linkage between genes controlling traits associated with mate recognition and genes controlling hybrid incompatibilities. She demonstrated that hybrid incompatibilities may develop under circumstances of increased linkage despite some gene flow and state that "postzygotic isolation may build up during the sympatric speciation process, accelerating and easing the conditions for speciation to proceed"

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