Sensory drive speciation and patterns of variation at selectively neutral genes

Tomotaka Matsumoto,Hidenori Tachida,Norihiro Okada,Yohey Terai

doi:10.1007/s10682-014-9697-8

Abstract

Speciation by sensory drive can occur if divergent adaptation of sensory systems causes rapid evolution of mating traits and the resulting development of assortative mating. Previous theoretical studies have shown that sensory drive can cause rapid divergent adaptive evolution from one to two phenotypes. In this study, we examined two topics: the possibility of adaptive radiation by sensory drive from one to more than two phenotypes and the relationships of patterns of variation at selectively neutral genes to levels of viability selection, habitat and mating preferences and migration. We conducted individual-based simulations assuming a sensory trait and a mating trait controlled by a small number of loci. We found that adaptive radiation is possible when the number of loci controlling the sensory trait is small; the levels of viability selection, habitat and mating preferences are intermediate; and the emigration rate is high. We also found that emigration rates as well as the levels of habitat and mating preferences are related to F ST values at neutral loci, but F ST proved to be insensitive to a small change in the number of loci controlling the mating trait. This suggests that an estimation of the past population history is possible without an accurate genetic model.

Highlights

Understanding the mechanisms of speciation is one of the most important research areas in evolutionary biology
We observed the population state in the simulations after 10,000 generations because the rapid adaptive radiation of the cichlids in Lake Victoria is believed to have occurred within approximately 10,000 years and because the generation time for Lake Victoria cichlids is 0.5–1 year/generation (Terai, personal communication)
We investigated two questions that have not been considered in previous studies: (1) the possibility of adaptive radiation caused by sensory drive in the presence of gene flow and (2) the effects of viability selection, habitat preference, mating preference and emigration rate on the patterns of variation at selectively neutral loci

Summary

Introduction

Understanding the mechanisms of speciation is one of the most important research areas in evolutionary biology. Visual systems adapted to different light environments recognize different coloration patterns as signals for choosing mating partners. Such visually mediated sensory drive is well documented in fishes such as guppies (Endler and Houde 1995), sticklebacks (Boughman 2001) and cichlids (Terai et al 2006; Seehausen et al 2008). The cichlids of Lake Victoria in East Africa, which consists of approximately 500 species (Seehausen 1996; Turner et al 2001), are of particular interest These species are monophyletic (Meyer et al 1990; Meyer 1993; Verheyen et al 2003), and they are thought to have undergone speciation within the last 10,000–15,000 years based on the geological history of the lake (Johnson et al 1996, 2000; Beuning et al 1997; Scholz et al 1998; Seehausen 2002). Sensory drive has been hypothesized to be one of the important mechanisms of this rapid adaptive radiation (Terai et al 2006; Seehausen et al 2008)

Results

Discussion

Conclusion