scholarly journals Community Genetics Reveal Elevated Levels of Sympatric Gene Flow among Morphologically Similar but Not among Morphologically Dissimilar Species of Lake Victoria Cichlid Fish

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
N. Konijnendijk ◽  
D. A. Joyce ◽  
H. D. J. Mrosso ◽  
M. Egas ◽  
O. Seehausen
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Lake Victoria ◽  
Cichlid Fish ◽  
Mechanistic Explanation ◽  
Sympatric Species ◽  
Community Genetics ◽  
Similar Species ◽  
Haplochromine Cichlids ◽  
Island Communities

We examined genetic structure among five species of Lake Victoria haplochromine cichlids in four island communities, using a full factorial sampling design that compared genetic differentiation between pairs of species and populations of varying morphological similarity and geographical proximity. We found that allopatric conspecific populations were on average significantly more strongly differentiated than sympatric heterospecific populations of morphologically similar species. Allopatric heterospecific populations of morphologically dissimilar species were most differentiated. Our work demonstrates that phenotypic divergence can be maintained and perhaps even evolve in sympatry despite considerable gene flow between species. Conversely, phenotypic resemblance among conspecific populations can be maintained despite geographical isolation. Additionally we show that anthropogenically increased hybridization does not affect all sympatric species evenly but predominantly affects morphologically similar and closely related species. This has important implications for the evolution of reproductive isolation between species These findings are also consistent with the hypothesis of speciation reversal due to weakening of divergent selection and reproductive isolation as a consequence of habitat homogenization and offers an evolutionary mechanistic explanation for the observation that species poor assemblages in turbid areas of the lake are characterized by just one or two species in each of a few morphologically distinct genera.

scholarly journals Genetic architecture of a key reproductive isolation trait differs between sympatric and non-sympatric sister species of Lake Victoria cichlids

2020 ◽  
Vol 287 (1924) ◽  
pp. 20200270
Author(s):  
Anna F. Feller ◽  
Marcel P. Haesler ◽  
Catherine L. Peichel ◽  
Ole Seehausen
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Related Species ◽  
Genetic Architecture ◽  
Lake Victoria ◽  
Sympatric Species ◽  
Sister Species ◽  
Species Pair ◽  
Closely Related Species ◽  
Nuptial Coloration

One hallmark of the East African cichlid radiations is the rapid evolution of reproductive isolation that is robust to full sympatry of many closely related species. Theory predicts that species persistence and speciation in sympatry with gene flow are facilitated if loci of large effect or physical linkage (or pleiotropy) underlie traits involved in reproductive isolation. Here, we investigate the genetic architecture of a key trait involved in behavioural isolation, male nuptial coloration, by crossing two sister species pairs of Lake Victoria cichlids of the genus Pundamilia and mapping nuptial coloration in the F2 hybrids. One is a young sympatric species pair, representative of an axis of colour motif differentiation, red-dorsum versus blue, that is highly recurrent in closely related sympatric species. The other is a species pair representative of colour motifs, red-chest versus blue, that are common in allopatric but uncommon in sympatric closely related species. We find significant quantitative trait loci (QTLs) with moderate to large effects (some overlapping) for red and yellow in the sympatric red-dorsum × blue cross, whereas we find no significant QTLs in the non-sympatric red-chest × blue cross. These findings are consistent with theory predicting that large effect loci or linkage/pleiotropy underlying mating trait differentiation could facilitate speciation and species persistence with gene flow in sympatry.

Sympatric colour polymorphisms associated with nonrandom gene flow in cichlid fish of Lake Victoria

2010 ◽  
Vol 19 (16) ◽  
pp. 3285-3300 ◽  
Author(s):  
I. S. MAGALHAES ◽  
S. MWAIKO ◽  
O. SEEHAUSEN
Keyword(s):  
Gene Flow ◽  
Lake Victoria ◽  
Cichlid Fish

scholarly journals Genome-wide patterns of divergence and introgression after secondary contact between Pungitius sticklebacks

2020 ◽  
Vol 375 (1806) ◽  
pp. 20190548 ◽  
Author(s):  
Yo Y. Yamasaki ◽  
Ryo Kakioka ◽  
Hiroshi Takahashi ◽  
Atsushi Toyoda ◽  
Atsushi J. Nagano ◽  
...  
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Sequence Data ◽  
Continuous Process ◽  
Sympatric Species ◽  
Whole Genome Sequence ◽  
Secondary Contact ◽  
Pungitius Pungitius ◽  
Hybrid Male ◽  
Differential Adaptation

Speciation is a continuous process. Although it is known that differential adaptation can initiate divergence even in the face of gene flow, we know relatively little about the mechanisms driving complete reproductive isolation and the genomic patterns of divergence and introgression at the later stages of speciation. Sticklebacks contain many pairs of sympatric species differing in levels of reproductive isolation and divergence history. Nevertheless, most previous studies have focused on young species pairs. Here, we investigated two sympatric stickleback species, Pungitius pungitius and P. sinensis , whose habitats overlap in eastern Hokkaido; these species show hybrid male sterility, suggesting that they may be at a late stage of speciation. Our demographic analysis using whole-genome sequence data showed that these species split 1.73 Ma and came into secondary contact 37 200 years ago after a period of allopatry. This long period of allopatry might have promoted the evolution of intrinsic incompatibility. Although we detected on-going gene flow and signatures of introgression, overall genomic divergence was high, with considerable heterogeneity across the genome. The heterogeneity was significantly associated with variation in recombination rate. This sympatric pair provides new avenues to investigate the late stages of the stickleback speciation continuum. This article is part of the theme issue ‘Towards the completion of speciation: the evolution of reproductive isolation beyond the first barriers’.

scholarly journals Developmental effects of environmental light on male nuptial coloration in Lake Victoria cichlid fish

2017 ◽  
Author(s):  
Daniel S. Wright ◽  
Emma Rietveld ◽  
Martine E. Maan
Keyword(s):  
Reproductive Isolation ◽  
Lake Victoria ◽  
Cichlid Fish ◽  
Light Condition ◽  
Male Reproductive Success ◽  
Light Conditions ◽  
Nuptial Coloration ◽  
Species Specific ◽  
Depth Ranges ◽  
Male Coloration

Background. Efficient communication requires that signals are well transmitted and perceived in a given environment. Natural selection therefore drives the evolution of different signals in different environments. In addition, environmental heterogeneity at small spatial or temporal scales may favour phenotypic plasticity in signaling traits, as plasticity may allow rapid adjustment of signal expression to optimize transmission. In this study, we explore signal plasticity in the nuptial coloration of Lake Victoria cichlids, Pundamilia pundamilia and Pundamilia nyererei. These two species differ in male coloration, which mediates species-assortative mating. They occur in adjacent depth ranges with different light environments. Given the close proximity of their habitats, overlapping at some locations, plasticity in male coloration could contribute to male reproductive success but interfere with reproductive isolation. Methods. We reared P. pundamilia, P. nyererei, and their hybrids under light conditions mimicking the two depth ranges in Lake Victoria. From photographs, we quantified the nuptial coloration of males, spanning the entire visible spectrum. In experiment 1, we examined developmental colour plasticity by comparing sibling males reared in each light condition. In experiment 2, we assessed colour plasticity in adulthood, by switching adult males between conditions and tracking coloration for 100 days. Results. We found that nuptial colour in Pundamilia did respond plastically to our light manipulations, but only in a limited hue range. Fish that were reared in light conditions mimicking the deeper habitat were significantly greener than those in conditions mimicking shallow waters. The species-specific nuptial colours (blue and red) did not change. When moved to the opposing light condition as adults, males did not change colour. Discussion. Our results show that species-specific nuptial colours, which are subject to strong divergent selection by female choice, are not plastic. We do find plasticity in green coloration, a response that may contribute to visual conspicuousness in darker, red-shifted light environments. These results suggest that light-environment-induced plasticity in male nuptial coloration in P. pundamilia and P. nyererei is limited and does not interfere with reproductive isolation.

scholarly journals Contribution of opsins and chromophores to cone pigment variation across populations of Lake Victoria cichlids

2021 ◽  
Author(s):  
Elodie Wilwert ◽  
Rampal S Etienne ◽  
Louis Van de Zande ◽  
Martine E Maan
Keyword(s):  
Lake Victoria ◽  
Expression Patterns ◽  
Cichlid Fish ◽  
Sympatric Species ◽  
Visual Sensitivity ◽  
Turbid Water ◽  
Cone Opsin ◽  
In The Wild ◽  
Environmental Causes ◽  
Pigment Variation

Adaptation to heterogeneous sensory environments has been implicated as a key parameter in speciation. Cichlid fish are a textbook example of divergent visual adaptation, mediated by variation in the sequences and expression levels of cone opsin genes (encoding the protein component of visual pigments). In some vertebrates including fish, visual sensitivity is also tuned by the ratio of Vitamin A1/A2-derived chromophores (i.e. the light-sensitive component of the visual pigment, bound to the opsin protein), where higher proportions of A2 cause a more red-shifted wavelength absorbance. Here, we explore variation in chromophore ratios across multiple cichlid populations in Lake Victoria, using as a proxy the enzyme CYP27C1 that catalyses the conversion of Vitamin A1- into A2. We focus on sympatric Pundamilia cichlids, where species with blue or red male coloration co-occur at multiple islands, but occupy different depths and consequently different visual habitats. In the red species, we found higher cyp27c1 expression in populations from turbid-water than from clear-water locations, but there was no such pattern in the blue species. Across populations, differences between the sympatric species in cyp27c1 expression had a consistent relationship with species differences in opsin expression patterns, but the red/blue identity reversed between clear- and turbid-water locations. To assess the contribution of heritable versus environmental causes of variation, we tested whether light manipulations induce a change in cyp27c1 expression in the laboratory. We found that cyp27c1 expression was not influenced by experimental light conditions, suggesting that the observed variation in the wild is due to genetic differences. Establishing the biological importance of this variation requires testing the link between cyp27c1 expression and A1/A2 ratios in the eye, as well as its consequences for visual performance.

scholarly journals Developmental effects of environmental light on male nuptial coloration in Lake Victoria cichlid fish

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4209 ◽  
Author(s):  
Daniel Shane Wright ◽  
Emma Rietveld ◽  
Martine E. Maan
Keyword(s):  
Reproductive Isolation ◽  
Lake Victoria ◽  
Cichlid Fish ◽  
Light Condition ◽  
Male Reproductive Success ◽  
Light Conditions ◽  
Nuptial Coloration ◽  
Species Specific ◽  
Depth Ranges ◽  
Male Coloration

BackgroundEfficient communication requires that signals are well transmitted and perceived in a given environment. Natural selection therefore drives the evolution of different signals in different environments. In addition, environmental heterogeneity at small spatial or temporal scales may favour phenotypic plasticity in signaling traits, as plasticity may allow rapid adjustment of signal expression to optimize transmission. In this study, we explore signal plasticity in the nuptial coloration of Lake Victoria cichlids,Pundamilia pundamiliaandPundamilia nyererei.These two species differ in male coloration, which mediates species-assortative mating. They occur in adjacent depth ranges with different light environments. Given the close proximity of their habitats, overlapping at some locations, plasticity in male coloration could contribute to male reproductive success but interfere with reproductive isolation.MethodsWe rearedP. pundamilia,P. nyererei,and their hybrids under light conditions mimicking the two depth ranges in Lake Victoria. From photographs, we quantified the nuptial coloration of males, spanning the entire visible spectrum. In experiment 1, we examined developmental colour plasticity by comparing sibling males reared in each light condition. In experiment 2, we assessed colour plasticity in adulthood, by switching adult males between conditions and tracking coloration for 100 days.ResultsWe found that nuptial colour inPundamiliadid respond plastically to our light manipulations, but only in a limited hue range. Fish that were reared in light conditions mimicking the deeper habitat were significantly greener than those in conditions mimicking shallow waters. The species-specific nuptial colours (blue and red) did not change. When moved to the opposing light condition as adults, males did not change colour.DiscussionOur results show that species-specific nuptial colours, which are subject to strong divergent selection by female choice, are not plastic. We do find plasticity in green coloration, a response that may contribute to visual conspicuousness in darker, red-shifted light environments. These results suggest that light-environment-induced plasticity in male nuptial coloration inP. pundamiliaandP. nyerereiis limited and does not interfere with reproductive isolation.

scholarly journals The importance of intrinsic postzygotic barriers throughout the speciation process

2020 ◽  
Vol 375 (1806) ◽  
pp. 20190533 ◽  
Author(s):  
Jenn M. Coughlan ◽  
Daniel R. Matute
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Rapid Evolution ◽  
Theoretical Work ◽  
Sympatric Species ◽  
Species Boundaries ◽  
Biological Models ◽  
Speciation Process ◽  
Species Pairs ◽  
Postzygotic Barriers

Intrinsic postzygotic barriers can play an important and multifaceted role in speciation, but their contribution is often thought to be reserved to the final stages of the speciation process. Here, we review how intrinsic postzygotic barriers can contribute to speciation, and how this role may change through time. We outline three major contributions of intrinsic postzygotic barriers to speciation. (i) reduction of gene flow : intrinsic postzygotic barriers can effectively reduce gene exchange between sympatric species pairs. We discuss the factors that influence how effective incompatibilities are in limiting gene flow. (ii) early onset of species boundaries via rapid evolution : intrinsic postzygotic barriers can evolve between recently diverged populations or incipient species, thereby influencing speciation relatively early in the process. We discuss why the early origination of incompatibilities is expected under some biological models, and detail how other (and often less obvious) incompatibilities may also serve as important barriers early on in speciation. (iii) reinforcement : intrinsic postzygotic barriers can promote the evolution of subsequent reproductive isolation through processes such as reinforcement, even between relatively recently diverged species pairs. We incorporate classic and recent empirical and theoretical work to explore these three facets of intrinsic postzygotic barriers, and provide our thoughts on recent challenges and areas in the field in which progress can be made. This article is part of the theme issue ‘Towards the completion of speciation: the evolution of reproductive isolation beyond the first barriers’.

Speciation

2003 ◽  
Author(s):  
Mary Jane West-Eberhard
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Developmental Plasticity ◽  
Sympatric Speciation ◽  
Similar Species ◽  
Host Shifts ◽  
Phenotypic Divergence ◽  
Alternative Phenotypes ◽  
Living Things ◽  
As Species

In sexually reproducing organisms, speciation is lineage branching—the origin of reproductive isolation between sister populations descended from a single interbreeding parent population. Obviously, speciation is a process of fundamental importance in evolution. In sexually reproducing organisms, every persistent branching point of a phylogenetic tree, whether between very similar species or higher taxa, reflects a speciation event. Because complete reproductive isolation means the end of gene flow between populations, there is no doubt that it can facilitate genetic and phenotypic divergence. So speciation is a major cause of the diversification of living things. In nonsexual or uniparental populations, isolation between divergent populations may also be called speciation, but reduced gene flow can play no role. Such populations may become genetically distinctive and divergent due to differences in mutation, selection, and drift and thereby qualify as species under some definitions (see M. B. Williams, 1992, for a discussion of the species concept in asexual organisms). This chapter deals only with speciation in sexually reproducing organisms. By the usual view of speciation, some barrier to interbreeding comes first, followed or accompanied by genetic and phenotypic divergence. Reproductive isolation leads to divergence. Here I argue that the reverse may sometimes occur—that divergence, mediated by developmental plasticity and selection, may sometimes originate first and contribute to the evolution of reproductive isolation. As discussed in part III, evolution by disruptive and frequencydependent selection can produce a developmental switch between alternative phenotypes rather than loss of intermediate genotypes. This is particularly well documented in insects, often leading to misidentification of intraspecific morphs as species. Since polymorphic insects may have host-associated morphs, host shifts accompanied by distinctive morphology cannot be assumed to represent sympatric speciation or host-race formation, and sympatric speciation hypotheses need to decisively eliminate the possibility of a role for sympatric divergence in the form of polymorphism or behavioral and physiological plasticity. Such intraspecific host shifts may contribute to speciation, whether sympatric or allopatric, as discussed further below.

scholarly journals Developmental effects of environmental light on male nuptial coloration in Lake Victoria cichlid fish

2017 ◽  
Author(s):  
Daniel S. Wright ◽  
Emma Rietveld ◽  
Martine E. Maan
Keyword(s):  
Reproductive Isolation ◽  
Lake Victoria ◽  
Cichlid Fish ◽  
Light Condition ◽  
Male Reproductive Success ◽  
Light Conditions ◽  
Nuptial Coloration ◽  
Species Specific ◽  
Depth Ranges ◽  
Male Coloration

Background. Efficient communication requires that signals are well transmitted and perceived in a given environment. Natural selection therefore drives the evolution of different signals in different environments. In addition, environmental heterogeneity at small spatial or temporal scales may favour phenotypic plasticity in signaling traits, as plasticity may allow rapid adjustment of signal expression to optimize transmission. In this study, we explore signal plasticity in the nuptial coloration of Lake Victoria cichlids, Pundamilia pundamilia and Pundamilia nyererei. These two species differ in male coloration, which mediates species-assortative mating. They occur in adjacent depth ranges with different light environments. Given the close proximity of their habitats, overlapping at some locations, plasticity in male coloration could contribute to male reproductive success but interfere with reproductive isolation. Methods. We reared P. pundamilia, P. nyererei, and their hybrids under light conditions mimicking the two depth ranges in Lake Victoria. From photographs, we quantified the nuptial coloration of males, spanning the entire visible spectrum. In experiment 1, we examined developmental colour plasticity by comparing sibling males reared in each light condition. In experiment 2, we assessed colour plasticity in adulthood, by switching adult males between conditions and tracking coloration for 100 days. Results. We found that nuptial colour in Pundamilia did respond plastically to our light manipulations, but only in a limited hue range. Fish that were reared in light conditions mimicking the deeper habitat were significantly greener than those in conditions mimicking shallow waters. The species-specific nuptial colours (blue and red) did not change. When moved to the opposing light condition as adults, males did not change colour. Discussion. Our results show that species-specific nuptial colours, which are subject to strong divergent selection by female choice, are not plastic. We do find plasticity in green coloration, a response that may contribute to visual conspicuousness in darker, red-shifted light environments. These results suggest that light-environment-induced plasticity in male nuptial coloration in P. pundamilia and P. nyererei is limited and does not interfere with reproductive isolation.

scholarly journals Early learning influences species assortative mating preferences in Lake Victoria cichlid fish

2007 ◽  
Vol 3 (2) ◽  
pp. 134-136 ◽  
Author(s):  
Machteld N Verzijden ◽  
Carel ten Cate
Keyword(s):  
Reproductive Isolation ◽  
Assortative Mating ◽  
Lake Victoria ◽  
Cichlid Fish ◽  
Species Flock ◽  
Mating Preferences ◽  
Sexual Imprinting ◽  
Cichlid Species ◽  
Young Females ◽  
Genetic Mechanisms

The Lake Victoria ‘species flock’ of cichlids is puzzling because reproductive isolation often occurs in the absence of substantial ecological differences among species. Theory predicts that this cannot evolve with most genetic mechanisms for mate choice. We provide the first evidence that learning, in the form of sexual imprinting, helps maintain reproductive isolation among closely related cichlid species. Using a cross-fostering experiment, we show that young females develop a sexual preference for males of their foster mothers' species, even reversing species assortative mating preferences. We suggest that learning creates favourable conditions for reproductive isolation to evolve.

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