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Emilio Rolanalvarez - One of the best experts on this subject based on the ideXlab platform.
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size selection by a gape limited predator of a marine snail insights into magic traits for speciation
Ecology and Evolution, 2017Co-Authors: Emilio Rolanalvarez, Elizabeth G Boulding, Maria Jose Rivas, Nerea Gonzalezlavin, Juan GalindoAbstract:The intertidal snail Littorina saxatilis has repeatedly evolved two parallel Ecotypes assumed to be wave adapted and predatory shore crab adapted, but the magnitude and targets of predator‐driven selection are unknown. In Spain, a small, wave Ecotype with a large aperture from the lower shore and a large, thick‐shelled crab Ecotype from the upper shore meet in the mid‐shore and show partial size‐assortative mating. We performed complementary field tethering and laboratory predation experiments; the first set compared the survival of two different size‐classes of the crab Ecotype while the second compared the same size‐class of the two Ecotypes. In the first set, the large size‐class of the crab Ecotype survived significantly better than the small size‐class both on the upper shore and in the laboratory. In the second set, the small size‐class of the crab Ecotype survived substantially better than that of the wave Ecotype both on the upper shore and in the laboratory. Shell‐breaking predation on tethered snails was almost absent within the lower shore. In the laboratory shore crabs (Pachygrapsus marmoratus) with larger claw heights selected most strongly against the small size‐class of the crab Ecotype, whereas those with medium claw heights selected most strongly against the thin‐shelled wave Ecotype. Sexual maturity occurred at a much larger size in the crab Ecotype than in the wave Ecotype. Our results showed that selection on the upper shore for rapid attainment of a size refuge from this gape‐limited predator favors large size, thick shells, and late maturity. Model parameterization showed that size‐selective predation restricted to the upper shore resulted in the evolution of the crab Ecotype despite gene flow from the wave Ecotype snails living on the lower shore. These results on gape‐limited predation and previous ones showing size‐assortative mating between Ecotypes suggest that size may represent a magic trait for the thick‐shelled Ecotype.
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proteomic evidence of a paedomorphic evolutionary process within a marine snail species a strategy for adapting to extreme ecological conditions
Journal of Evolutionary Biology, 2012Co-Authors: Paez M De La Cadena, Emilio RolanalvarezAbstract:The exposed and sheltered Ecotypes of the marine snail Littorina saxatilis from European rocky shores are considered a key model system to study adaptation and ecological speciation. Previous studies showed that two Ecotypes (RB and SU) of this species in NW Spain have adapted differently to different shore levels and microhabitats. In order to understand how this divergent adaptive process has been accomplished, we followed a quantitative proteomic approach to investigate the proteome variation in a number of different biological factors, that is, Ecotype, ontogeny and their interactions. This approach allowed testing the hypothesis that one of the Ecotypes has evolved by paedomorphosis, and also whether or not the molecular mechanisms related to Ecotype differentiation are set up in early developmental stages. Additionally, the identification of some candidate proteins using mass spectrometry provides some functional insights into these evolutionary processes. Results from this study provided evidence of higher ontogenetic differentiation at proteome level in the RB (metamorphic) than in SU (paedomorphic) Ecotype that point to the possibility of juvenile stage retention in this latter Ecotype. The level of protein expression (proteome) differences between Ecotypes maintained nearly constant from late embryonic stages to adulthood, although some proteins involved in these changes considerably differed in embryonic compared to other ontogenetic stages. Paedomorphosis may be the evolutionary response of the SU Ecotype of solving the trade-off during sexually immaturity that is caused by the evolution of small size arising from adaptation to the wave-exposed habitat. Some potential candidate genes of adaptation related to energetic metabolism have been identified, providing a promising baseline for future functional analyses.
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repeated evolution of reproductive isolation in a marine snail unveiling mechanisms of speciation
Philosophical Transactions of the Royal Society B, 2010Co-Authors: Kerstin Johannesson, Emilio Rolanalvarez, Petri Kemppainen, Marina Panova, Carl Andre, Roger K. ButlinAbstract:Distinct Ecotypes of the snail Littorina saxatilis, each linked to a specific shore microhabitat, form a mosaic-like pattern with narrow hybrid zones in between, over which gene flow is 10–30% of within-Ecotype gene flow. Multi-locus comparisons cluster populations by geographic affinity independent of Ecotype, while loci under selection group populations by Ecotype. The repeated occurrence of partially reproductively isolated Ecotypes and the conflicting patterns in neutral and selected genes can either be explained by separation in allopatry followed by secondary overlap and extensive introgression that homogenizes neutral differences evolved under allopatry, or by repeated evolution in parapatry, or in sympatry, with the same Ecotypes appearing in each local site. Data from Spain, the UK and Sweden give stronger support for a non-allopatric model of Ecotype formation than for an allopatric model. Several different non-allopatric mechanisms can, however, explain the repeated evolution of the Ecotypes: (i) parallel evolution by new mutations in different populations; (ii) evolution from standing genetic variation; and (iii) evolution in concert with rapid spread of new positive mutations among populations inhabiting similar environments. These models make different predictions that can be tested using comprehensive phylogenetic information combined with candidate loci sequencing.
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genetic variation for shell traits in a direct developing marine snail involved in a putative sympatric ecological speciation process
Evolutionary Ecology, 2007Co-Authors: Paula Condepadin, Antonio Carvajalrodriguez, M Carballo, Armando Caballero, Emilio RolanalvarezAbstract:Populations of the marine gastropod Littorina saxatilis from exposed rocky shores of NW Spain provide one of the few putative cases of sympatric ecological speciation. Two Ecotypes with large differences in shell morphology and strong assortative mating are living at different vertical levels of the shore separated by a few meters. It has been hypothesized that shell size is the main determinant for the reproductive isolation observed between the Ecotypes, and that several shell shape traits are subject to divergent natural selection and are responsible for the adaptation of each Ecotype to its respective habitat. Using embryos extracted from wild females we obtain estimates of genetic variation for shell size and shape and compare them with those from neutral molecular markers. Estimates of heritability are significantly larger for the Ecotype found in the upper shore than for that in the lower shore, in concordance with a similar result observed for heterozygosity of neutral markers. The large genetic differentiation between Ecotypes for the shell traits, contrasting the smaller close to neutral differentiation between populations of the same Ecotype, supports the implication of the traits in adaptation.
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decomposing shell form into size and shape by geometric morphometric methods in two sympatric Ecotypes of littorina saxatilis
Journal of Molluscan Studies, 2005Co-Authors: Antonio Carvajalrodriguez, Paula Condepadin, Emilio RolanalvarezAbstract:Two sympatric snail Ecotypes (RB and SU) of Littorina saxatilis from exposed rocky shores of NW Spain differ in many life history traits, but classical morphometric analysis has failed to reveal significant shell shape differences between them. We used geometric morphometric methods on landmark data from digitized shell images to study size and shape components in both Ecotypes at two localities. The results showed significant differences between Ecotypes in both shell size and shape (both uniform and non-uniform components). Allometry was also detected for some component of the local variation in shape, although it did not explain the observed differences between Ecotypes. The SU Ecotype had a relatively rounded shell shape with a big aperture, whereas the RB Ecotype had higher spire and smaller aperture. We suggest that shape differentiation is correlated with adaptive differences between Ecotypes.
Evan Siemann - One of the best experts on this subject based on the ideXlab platform.
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the effect of chinese tallow tree sapium sebiferum Ecotype on soil plant system carbon and nitrogen processes
Oecologia, 2006Co-Authors: Jianwen Zou, William E Rogers, Saara J Dewalt, Evan SiemannAbstract:The EICA hypothesis predicts that shifts in allocation of invasive plants give rise to higher growth rates and lower herbivore defense levels in their introduced range than conspecifics in their native range. These changes in traits of invasive plants may also affect ecosystem processes. We conducted an outdoor pot experiment with Chinese tallow tree (Sapium sebiferum, Euphorbiaceae) seedlings from its native (Jiangsu, China, native Ecotype) and introduced ranges (Texas, USA, invasive Ecotype) to compare their relative performances in its native range and to examine Ecotype effects on soil processes with and without fertilization. Consistent with predictions, plant (shoot and root) mass was significantly greater and leaf defoliation tended to be higher, while the root:shoot ratio was lower for the invasive Ecotype relative to the native Ecotype. Seasonal amounts of soil–plant system CO2 and N2O emissions were higher for the invasive Ecotype than for the native Ecotype. Soil respiration rates and N2O emission increases from fertilization were also greater for the invasive Ecotype than for the native Ecotype, while shoot-specific respiration rates (g CO2–C g−1 C day−1) did not differ between Ecotypes. Further, soil inorganic N (ammonium and nitrate) was higher, but soil total N was lower for soils with the invasive Ecotype than soils with the native Ecotype. Compared with native Ecotypes, therefore, invasive Ecotypes may have developed a competition advantage in accelerating soil processes and promoting more nitrogen uptake through soil–plant direct interaction. The results of this study suggest that soil and ecosystem processes accelerated by variation in traits of invasive plants may have implications for their invasiveness.
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Invasive Ecotypes tolerate herbivory more effectively than native Ecotypes of the Chinese tallow tree Sapium sebiferum
Journal of Applied Ecology, 2004Co-Authors: William E Rogers, Evan SiemannAbstract:Summary 1. The evolution of increased competitive ability (EICA) hypothesis proposes that exotic plants often become invasive because they have evolved reduced allocation to defence and increased allocation to growth and reproduction in response to low herbivore loads. Previous studies with Chinese tallow tree Sapium sebiferum support EICA predictions of invasive North American Ecotypes displaying rapid growth, poorly defended leaves and considerable compensation after defoliation. In contrast, native Asian Ecotypes are comparatively slow growing with highly defended leaves and are negatively impacted by mechanical leaf damage. The effects of root damage on the different Ecotypes are unknown. 2. We conducted a full-factorial pot experiment designed to assess the effects of soil fertility, competition with ryegrass Lolium multiflorum and mechanical root damage on Sapium seedlings derived from seed collections obtained in the ancestral range (native Chinese Ecotype) and introduced range (invasive Texas Ecotype). 3. The results, consistent with EICA predictions, revealed that Chinese Ecotypes were negatively affected by severing roots, while Texas Ecotypes were able to compensate for root damage. 4. Fertilization increased growth of Chinese Ecotypes, but did not reduce the negative effects of root damage enough to allow the seedlings to compensate completely. Competition increased the stem height growth of Chinese Ecotypes, but did not affect shoot or root mass. Texas Ecotypes were not significantly affected by any experimental treatments. 5. Synthesis and applications . The results of this study are consistent with previous studies indicating that invasive Sapium has undergone a shift away from possessing costly herbivore defences to producing relatively inexpensive tissues that are capable of rapidly compensating for damage. Evolutionary change is increasingly being recognized as an important factor contributing to the success of exotic plant invaders. Understanding that herbivory tolerance and the compensatory capacity for damage may differ between native and introduced plant Ecotypes will be essential for implementing effective control strategies for problematic invasive species.
S P Mcgrath - One of the best experts on this subject based on the ideXlab platform.
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synthesis of low molecular weight thiols in response to cd exposure in thlaspi caerulescens
Plant Cell and Environment, 2006Co-Authors: Javier Hernandezallica, Jose Maria Carrillo Becerril, Oihana Barrutia, Jose Ignacio Garciaplazaola, Fang-jie Zhao, Carlos Garbisu, S P McgrathAbstract:In this study, we investigated the accumulation of phytochelatins (PCs) and other low molecular weight (LMW) thiols in response to Cd exposure in two contrasting Ecotypes differing in Cd accumulation. Using a root elongation test, we found that the highly accumulating Ecotype Ganges was more tolerant to Cd than the low Cd-accumulation Ecotype Prayon. l-buthionine-(S,R)-sulphoximine (BSO), a potent inhibitor of the γ-glutamylcysteine synthetase (γ-ECS) (an enzyme involved in the PC biosynthetic pathway), increased the Cd sensitivity of Prayon, but had no effect on Ganges. Although PC accumulation increased in response to Cd exposure, no significant differences were observed between the two Ecotypes. Cd exposure induced a dose-dependent accumulation of both Cys and a still unidentified LMW thiol in roots of both Ecotypes. Root accumulation of Cys and this thiol was higher in Ganges than in Prayon; the ecotypic differences were more pronounced when the plants were treated with BSO. These findings suggest that PCs do not contribute to the Cd hypertolerance displayed by the Ganges Ecotype of Thlaspi caerulescens, whereas Cys and other LMW thiols might be involved.
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influence of iron status on cadmium and zinc uptake by different Ecotypes of the hyperaccumulator thlaspi caerulescens
Plant Physiology, 2002Co-Authors: Enzo Lombi, Fang-jie Zhao, Kathryn L Tearall, J R Howarth, Malcolm J Hawkesford, S P McgrathAbstract:We have previously identified an Ecotype of the hyperaccumulator Thlaspi caerulescens (Ganges), which is far superior to other Ecotypes (including Prayon) in Cd uptake. In this study, we investigated the effect of Fe status on the uptake of Cd and Zn in the Ganges and Prayon Ecotypes, and the kinetics of Cd and Zn influx using radioisotopes. Furthermore, the T. caerulescens ZIP (Zn-regulated transporter/Fe-regulated transporter-like protein) genes TcZNT1-G and TcIRT1-G were cloned from the Ganges Ecotype and their expression under Fe-sufficient and -deficient conditions was analyzed. Both short- and long-term studies revealed that Cd uptake was significantly enhanced by Fe deficiency only in the Ganges Ecotype. The concentration-dependent kinetics of Cd influx showed that the V max of Cd was 3 times greater in Fe-deficient Ganges plants compared with Fe-sufficient plants. In Prayon, Fe deficiency did not induce a significant increase in V max for Cd. Zn uptake was not influenced by the Fe status of the plants in either of the Ecotypes. These results are in agreement with the gene expression study. The abundance of ZNT1-G mRNA was similar between the Fe treatments and between the two Ecotypes. In contrast, abundance of the TcIRT1-G mRNA was greatly increased only in Ganges root tissue under Fe-deficient conditions. The present results indicate that the stimulatory effect of Fe deficiency on Cd uptake in Ganges may be related to an up-regulation in the expression of genes encoding for Fe 2+ uptake, possibly TcIRT1-G .
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characteristics of cadmium uptake in two contrasting Ecotypes of the hyperaccumulator thlaspi caerulescens
Journal of Experimental Botany, 2002Co-Authors: Fang-jie Zhao, Rebecca Hamon, Enzo Lombi, Mike J Mclaughlin, S P McgrathAbstract:Uptake of Cd and Zn by intact seedlings of two contrasting Ecotypes of the hyperaccumulatorThlaspi caerulescens was characterized using radioactive tracers. Uptake of Cd and Zn at 2 8C was assumed to represent mainly apoplastic binding in the roots, whereas the difference in uptake between 22 8C and 2 8C represented metabolically dependent influx. There was no significant difference between the two Ecotypes in the apoplastic binding of Cd or Zn. Metabolically dependent uptake of Cd was 4.5-fold higher in the high Cd-accumulating Ecotype, Ganges, than in the low Cd-accumulating Ecotype, Prayon. By contrast, there was only a 1.5-fold difference in the Zn uptake between the two Ecotypes. For the Ganges Ecotype, Cd uptake could be described by Michaelis–MentenkineticswithaVmaxof143 nmol g � 1 root FW h � 1 and a Km of 0.45 mM. Uptake of Cd by the Ganges Ecotype was not inhibited by La, Zn, Cu, Co, Mn, Ni or Fe(II), and neither by increasing the Ca concentration. By contrast, addition of La, Zn or Mn, or increasing the Ca concentration in the uptake solution decreased Cd uptake by Prayon. Uptake of Ca was larger in Prayon than in Ganges. The results suggest that Cd uptake by the low Cd-accumulating Ecotype (Prayon) may be mediated partly via Ca channels or transporters for Zn and Mn. By contrast, there may exist a highly selective Cd transport system in the root cell membranes of the high Cd-accumulating Ecotype (Ganges) of T. caerulescens.
William E Rogers - One of the best experts on this subject based on the ideXlab platform.
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the effect of chinese tallow tree sapium sebiferum Ecotype on soil plant system carbon and nitrogen processes
Oecologia, 2006Co-Authors: Jianwen Zou, William E Rogers, Saara J Dewalt, Evan SiemannAbstract:The EICA hypothesis predicts that shifts in allocation of invasive plants give rise to higher growth rates and lower herbivore defense levels in their introduced range than conspecifics in their native range. These changes in traits of invasive plants may also affect ecosystem processes. We conducted an outdoor pot experiment with Chinese tallow tree (Sapium sebiferum, Euphorbiaceae) seedlings from its native (Jiangsu, China, native Ecotype) and introduced ranges (Texas, USA, invasive Ecotype) to compare their relative performances in its native range and to examine Ecotype effects on soil processes with and without fertilization. Consistent with predictions, plant (shoot and root) mass was significantly greater and leaf defoliation tended to be higher, while the root:shoot ratio was lower for the invasive Ecotype relative to the native Ecotype. Seasonal amounts of soil–plant system CO2 and N2O emissions were higher for the invasive Ecotype than for the native Ecotype. Soil respiration rates and N2O emission increases from fertilization were also greater for the invasive Ecotype than for the native Ecotype, while shoot-specific respiration rates (g CO2–C g−1 C day−1) did not differ between Ecotypes. Further, soil inorganic N (ammonium and nitrate) was higher, but soil total N was lower for soils with the invasive Ecotype than soils with the native Ecotype. Compared with native Ecotypes, therefore, invasive Ecotypes may have developed a competition advantage in accelerating soil processes and promoting more nitrogen uptake through soil–plant direct interaction. The results of this study suggest that soil and ecosystem processes accelerated by variation in traits of invasive plants may have implications for their invasiveness.
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Invasive Ecotypes tolerate herbivory more effectively than native Ecotypes of the Chinese tallow tree Sapium sebiferum
Journal of Applied Ecology, 2004Co-Authors: William E Rogers, Evan SiemannAbstract:Summary 1. The evolution of increased competitive ability (EICA) hypothesis proposes that exotic plants often become invasive because they have evolved reduced allocation to defence and increased allocation to growth and reproduction in response to low herbivore loads. Previous studies with Chinese tallow tree Sapium sebiferum support EICA predictions of invasive North American Ecotypes displaying rapid growth, poorly defended leaves and considerable compensation after defoliation. In contrast, native Asian Ecotypes are comparatively slow growing with highly defended leaves and are negatively impacted by mechanical leaf damage. The effects of root damage on the different Ecotypes are unknown. 2. We conducted a full-factorial pot experiment designed to assess the effects of soil fertility, competition with ryegrass Lolium multiflorum and mechanical root damage on Sapium seedlings derived from seed collections obtained in the ancestral range (native Chinese Ecotype) and introduced range (invasive Texas Ecotype). 3. The results, consistent with EICA predictions, revealed that Chinese Ecotypes were negatively affected by severing roots, while Texas Ecotypes were able to compensate for root damage. 4. Fertilization increased growth of Chinese Ecotypes, but did not reduce the negative effects of root damage enough to allow the seedlings to compensate completely. Competition increased the stem height growth of Chinese Ecotypes, but did not affect shoot or root mass. Texas Ecotypes were not significantly affected by any experimental treatments. 5. Synthesis and applications . The results of this study are consistent with previous studies indicating that invasive Sapium has undergone a shift away from possessing costly herbivore defences to producing relatively inexpensive tissues that are capable of rapidly compensating for damage. Evolutionary change is increasingly being recognized as an important factor contributing to the success of exotic plant invaders. Understanding that herbivory tolerance and the compensatory capacity for damage may differ between native and introduced plant Ecotypes will be essential for implementing effective control strategies for problematic invasive species.
Kerstin Johannesson - One of the best experts on this subject based on the ideXlab platform.
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shared and nonshared genomic divergence in parallel Ecotypes of littorina saxatilis at a local scale
Molecular Ecology, 2016Co-Authors: Kerstin Johannesson, Roger K. Butlin, Carl Andre, Mark Ravinet, Anja M Westram, Marina PanovaAbstract:Parallel speciation occurs when selection drives repeated, independent adaptive divergence that reduces gene flow between Ecotypes. Classical examples show parallel speciation originating from shared genomic variation, but this does not seem to be the case in the rough periwinkle (Littorina saxatilis) that has evolved considerable phenotypic diversity across Europe, including several distinct Ecotypes. Small ‘wave’ Ecotype snails inhabit exposed rocks and experience strong wave action, while thick-shelled, ‘crab’ Ecotype snails are larger and experience crab predation on less exposed shores. Crab and wave Ecotypes appear to have arisen in parallel, and recent evidence suggests only marginal sharing of molecular variation linked to evolution of similar Ecotypes in different parts of Europe. However, the extent of genomic sharing is expected to increase with gene flow and more recent common ancestry. To test this, we used de novo RAD-sequencing to quantify the extent of shared genomic divergence associated with phenotypic similarities amongst Ecotype pairs on three close islands (<10 km distance) connected by weak gene flow (Nm ~ 0.03) and with recent common ancestry (<10 000 years). After accounting for technical issues, including a large proportion of null alleles due to a large effective population size, we found ~8–28% of positive outliers were shared between two islands and ~2–9% were shared amongst all three islands. This low level of sharing suggests that parallel phenotypic divergence in this system is not matched by shared genomic divergence despite a high probability of gene flow and standing genetic variation.
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preference of males for large females causes a partial mating barrier between a large and a small Ecotype of littorina fabalis w turton 1825
Journal of Molluscan Studies, 2013Co-Authors: Sara Hintz Saltin, Hanna Schade, Kerstin JohannessonAbstract:Species occupying different ecological niches may evolve Ecotypes that differ in size as a result of divergent selection on this trait. Size differences may affect mate preference and cause deviations from random mating. Several marine snails of the genus Littorina have Ecotypes that differ in size and earlier studies have shown strong assortative mating between differently sized Ecotypes in at least one of these species, L. saxatilis. Here we studied male mate choice in two Ecotypes of the congeneric L. fabalis that differ in size. We found mating to be nonrandom, because males of the large Ecotype followed the mucus trails and copulated with females of their own large Ecotype more than with females of the smaller Ecotype. Males of the smaller Ecotype showed no strong preference, but tended to copulate more with females of the large Ecotype than with their own females. Further experiments using the small Ecotype showed that mate choice was size-based, with a general preference of the males to mate large females. It seems likely that the partial reproductive barrier that we describe somewhat impedes gene flow between the two Ecotypes of L. fabalis, a result that corroborates earlier observations of a weak, but significant, gene-flow barrier across zones where the two Ecotypes overlap and hybridize.
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repeated evolution of reproductive isolation in a marine snail unveiling mechanisms of speciation
Philosophical Transactions of the Royal Society B, 2010Co-Authors: Kerstin Johannesson, Emilio Rolanalvarez, Petri Kemppainen, Marina Panova, Carl Andre, Roger K. ButlinAbstract:Distinct Ecotypes of the snail Littorina saxatilis, each linked to a specific shore microhabitat, form a mosaic-like pattern with narrow hybrid zones in between, over which gene flow is 10–30% of within-Ecotype gene flow. Multi-locus comparisons cluster populations by geographic affinity independent of Ecotype, while loci under selection group populations by Ecotype. The repeated occurrence of partially reproductively isolated Ecotypes and the conflicting patterns in neutral and selected genes can either be explained by separation in allopatry followed by secondary overlap and extensive introgression that homogenizes neutral differences evolved under allopatry, or by repeated evolution in parapatry, or in sympatry, with the same Ecotypes appearing in each local site. Data from Spain, the UK and Sweden give stronger support for a non-allopatric model of Ecotype formation than for an allopatric model. Several different non-allopatric mechanisms can, however, explain the repeated evolution of the Ecotypes: (i) parallel evolution by new mutations in different populations; (ii) evolution from standing genetic variation; and (iii) evolution in concert with rapid spread of new positive mutations among populations inhabiting similar environments. These models make different predictions that can be tested using comprehensive phylogenetic information combined with candidate loci sequencing.
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male discrimination of female mucous trails permits assortative mating in a marine snail species
Evolution, 2008Co-Authors: Kerstin Johannesson, Annika Sundin, Jonathan N Havenhand, Per R Jonsson, Mats Lindegarth, Johan HollanderAbstract:Recent research has shown the potential for nonallopatric speciation, but we lack an adequate understanding of the mechanisms of prezygotic barriers and how these evolve in the presence of gene flow. The marine snail Littorina saxatilis has distinct Ecotypes in different shore microhabitats. Ecotypes hybridize in contact zones, but gene flow is impeded by assortative mating. Earlier studies have shown that males and females of the same Ecotype copulate for longer than mates of different Ecotype. Here we report a new mechanism that further contributes to reproductive isolation between Ecotypes in the presence of gene flow. This mechanism is linked to the ability of males to track potential partners by following their mucous trail. We show that cliff Ecotype males follow the trails of females of the same Ecotype for longer than females of the alternate (boulder) Ecotype. In addition, cliff males are more likely to follow the mucous trail in the correct direction if the trail is laid by a cliff-female. The capacity to discriminate the Ecotype of female mucous trails combined with differential copulation times creates a strong prezygotic reproductive barrier between Ecotypes of L. saxatilis that reduces gene flow from cliff to boulder Ecotypes by ≥80%.
