Leaf morphological variation in beech (Fagus sylvatica L.) populations in Greece and its relation to their post‐glacial origin

Diversity in leaf morphological traits was assessed in 38 Greek Fagus sylvatica populations, covering the distribution of the species in the country. The relationship between the post‐glacial origin of these populations and leaf morphology was investigated. The results showed a complex and geographically continuous morphological diversity pattern, influenced mainly by traits expressing leaf size, leaf shape and petiole length. Two simultaneous trends appeared to be responsible for the existing diversity pattern. One was geographical, with leaf types resembling F. sylvatica subsp. sylvatica occurring in the western part of the distribution of beech in Greece and types resembling F. sylvatica subsp. orientalis being dominant in the eastern part. A second trend seemed to be connected with the post‐glacial origin of the populations, as described by previous plastid DNA haplotype studies of the same trees. The genetic background and the possible adaptation of beech populations to different environmental conditions have resulted in a complex morphological pattern, especially in areas in which different post‐glacial lineages appear to meet. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 165 , 422–436.     

Reticulate evolution patterns in western-Eurasian beeches

Reticulate evolution resulting from gene flow among diverged taxa was studied on the example of the Fagus sylvatica species complex in Europe and western Asia. F. sylvatica L. is one of the most widespread woody species of the Northern Hemisphere with two commonly recognized subspecies (namely, F. sylvatica subsp. sylvatica and F. sylvatica subsp. orientalis) and two putatively hybridogenous or intermediate taxa (F. moesiaca and F. taurica). Whereas the distribution of F. sylvatica subsp. sylvatica in Europe is almost continuous, the Asian range of F. sylvatica subsp. orientalis is fragmented into several larger regional populations. We studied genetic variation at 12 allozyme loci in 279 local subpopulations to assess whether previous contacts of regional populations left traces in their gene pools. Two approaches were used to infer potential reticulations: the reticulate network (Makarenkov and Legendre in J Comp Biol 11:195–212, 2004) and the neighbor-net network (Bryant and Moulton in Mol Biol Evol 21:255–265, 2004). A UPGMA dendrogram based on genetic distances between local populations revealed a high differentiation level within subsp. orientalis, whereby populations from Asia Minor, the Caucasus and the Alborz mts. were placed in different clusters. The reticulated network showed possible connections among adjacent populations, putatively resulting from previous contacts. The neighbor-net network also consisted of two major groups corresponding to F. sylvatica s. str. + F. moesiaca and F. orientalis including F. taurica. Regional populations of F. moesiaca are placed close to the basis of the European branch and are highly networked, indicating ambiguity in the phylogenetic signal. Similarly, three subgroups can be distinguished within the F. orientalis group and correspond well with broad regions of Asia Minor, the Caucasus and the Alborz. The Amanus regional population is intermediary between the subgroup of Asia Minor and the Caucasian subgroup. Crimean populations (i.e., putative hybrids) are placed near the basis of the subgraph. Two explanations of the observed reticulations are discussed: expansions and retreats of the range of beech associated with Pliocene and Pleistocene climatic fluctuations, resulting in contacts and exchanges of gene pools among regional populations, and sharing ancestral polymorphisms due to incomplete lineage sorting.     

Geographical patterns of genetic variation in rosemary (Rosmarinus officinalis) in the Mediterranean basin

Climate changes during the Quaternary had important effects on the evolution of European plant species. The distribution of genetic variability in rosemary, a strictly Mediterranean species of reputed Plio‐Quaternary origin for which the diversification centre is hypothesized to be located in the western part of the Mediterranean basin, was investigated across the species range by using plastid microsatellites [plastid simple sequence repeat (cpSSR)] markers. Seven out of the 17 primer pairs screened were polymorphic, with up to four alleles, yielding a total of 17 size variants combined into ten haplotypes. A permutation test to investigate for geographical structure showed no significant differences between R_ST and G_ST, indicating that the species lacks geographical structure. Low correlation between genetic and geographical distances was shown by the Mantel test. Bayesian analysis identified two coancestry groups of populations. The distribution of genetic diversity supports the hypothesized origin in the western Mediterranean basin, and with the demographic expansion test indicates three different routes of migration: a northern route expanding along the northern side of the Mediterranean and two southern routes, one from west to east through North Africa and reaching Cyrenaica, and a second to the south‐west of the Iberian Peninsula, from where it came back to the south–central areas. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013 , 171 , 700–712.     

Parallel evolution of insular Olea europaea subspecies based on geographical structuring of plastid DNA variation and phenotypic similarity in leaf traits

Strong geographical isolation within the distribution of a species may result in differentiated lineages exhibiting conspicuous phenotypic differences. In the present paper, we investigate whether plastid and phenotypic variation is geographically structured within the Olea europaea complex in Macaronesia, which comprises three subspecies separated by oceanic barriers: maroccana (south‐west Morocco), guanchica (Canary Islands) and cerasiformis (Madeira archipelago). Plastid variation showed a significant pattern of geographical structure (N_ST > G_ST = 0.56), because of the lack of shared haplotypes among subspecies and the presence of a single and private haplotype in the eastern Canary Islands. Such a clear molecular structure, however, was not reflected in a congruent pattern of phenotypic differentiation among taxa in leaf morpho‐functional traits. Despite the substantial genetic differentiation observed between the subspecies from Madeira and the Canary Islands, they displayed both higher leaf size (leaf area) and specific leaf area (leaf surface area‐to‐mass ratio) than their continental counterparts, probably as a result of oceanic conditions in subtropical environments. Unlike most of the plant groups previously studied in the Macaronesian region, the lineages of Olea illustrate how low phenotypic differentiation can be also related to a clear molecular differentiation in oceanic island enclaves. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 162 , 54–63.     

Phylogeography of a mite,Halozetes fulvus,reflects the landscape history of a young volcanic island in the sub‐Antarctic

Previous studies of the microarthropods of Marion Island, Southern Ocean, documented high mitochondrial COI (cytochrome c oxidase subunit I) haplotype diversity and significant genetic structure, which were ascribed to landscape subdivision. In this paper we revisit these ideas in light of new geomorphological evidence indicating a major lineament orientated along N26.5°E. Using the microarthropod Halozetes fulvus, we test the hypothesis that the eastern and western sides of the island show different population genetic patterns, corresponding to the previously unrecognized geological separation of these regions, and perhaps also with differences in climates across the island and further landscape complexity. Mitochondrial COI data were collected for 291 H. fulvus individuals from 30 localities across the island. Notwithstanding our sampling effort, haplotype diversity was under‐sampled as indicated by rarefaction analyses. Overall, significant genetic structure was found across the island as indicated by Φ_ST analyses. Nested clade phylogeographical analyses suggested that restricted gene flow (with isolation‐by‐distance) played a role in shaping current genetic patterns, as confirmed by Mantel tests. At the local scale, coalescent modelling revealed two different genetic patterns. The first, characterizing populations on the south‐western corner of the island, was that of low effective population size and high gene flow. The converse was found on the eastern side of Marion Island. Taken together, substantial differences in spatial genetic structure characterize H. fulvus populations across Marion Island, in keeping with the hypothesis that the complex history of the island, including the N26.5°E geological lineament, has influenced population genetic structure. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 131–145.     

Chloroplast DNA phylogeography of the hornbeam in Europe: Evidence for a bottleneck at the outset of postglacial colonization

The hornbeam, a shade tolerant tree species,has recolonised Europe very late during theHolocene. In order to investigate whether thispostglacial recolonisation had led to a loss ofchloroplast (cp) DNA diversity, as alreadydescribed for other tree species, andespecially the beech, another late-successionalspecies, we have studied the phylogeography ofthe hornbeam using cpDNA. Three types of cpDNAmarkers were used (PCR-RFLP, microsatellites,sequences) to analyse 36 European populationsof C. betulus and five populations ofC. orientalis. Six haplotypes specific toC. betulus were detected, one of themcompletely fixed in all populations fromnorthern and western Europe, whereas the otherswere restricted to the eastern Europeancountries and to southern Italy. A remarkablyhigh value of differentiation among populationswas found (G _ST = 0.972). Twodifferent haplotypes specific to C.orientalis were detected, suggesting noongoing gene flow between these two species,and similar refugia in Italy and in the Balkansfor both Carpinus species. Pollen dataare congruent with genetic data: during thelast ice age, the hornbeam was restricted tothe Balkans and to southern Italy andrecolonised Europe northwards and westwards.Conservation priorities should target severalpopulations from these regions that arehotspots of diversity and that represent asmall part of the range of the species.     

Climate‐associated genetic variation in Fagus sylvatica and potential responses to climate change in the French Alps

Local adaptation patterns have been found in many plants and animals, highlighting the genetic heterogeneity of species along their range of distribution. In the next decades, global warming is predicted to induce a change in the selective pressures that drive this adaptive variation, forcing a reshuffling of the underlying adaptive allele distributions. For species with low dispersion capacity and long generation time such as trees, the rapidity of the change could impede the migration of beneficial alleles and lower their capacity to track the changing environment. Identifying the main selective pressures driving the adaptive genetic variation is thus necessary when investigating species capacity to respond to global warming. In this study, we investigate the adaptive landscape of Fagus sylvatica along a gradient of populations in the French Alps. Using a double‐digest restriction‐site‐associated DNA (ddRAD) sequencing approach, we identified 7,000 SNPs from 570 individuals across 36 different sites. A redundancy analysis (RDA)‐derived method allowed us to identify several SNPs that were strongly associated with climatic gradients; moreover, we defined the primary selective gradients along the natural populations of F. sylvatica in the Alps. Strong effects of elevation and humidity, which contrast north‐western and south‐eastern site, were found and were believed to be important drivers of genetic adaptation. Finally, simulations of future genetic landscapes that used these findings allowed identifying populations at risk for F. sylvatica in the Alps, which could be helpful for future management plans.     

Does predation drive morphological differentiation among Adriatic populations of the three‐spined stickleback?

Morphometric differentiation among freshwater fish populations is a commonplace occurrence, although the underlying causes for this divergence often remain elusive. We analysed the degree and patterns of morphological differentiation among nine freshwater three‐spined stickleback (Gasterosteus aculeatus) populations inhabiting isolated karst rivers of the Adriatic Sea basin, to characterise the phenotypic diversity and differentiation in these populations. The analyses revealed marked and significant morphometric differentiation – especially in traits related to predator defence amongst most populations – even among those located within close geographic proximity in the same catchment system. Accordingly, the degree of morphometric and neutral genetic differentiation, as assessed from variability in 15 microsatellite loci from a parallel study, were uncorrelated across the populations. However, P_ST/F_ST comparisons revealed that the degree of phenotypic differentiation (P_ST) among populations exceeded that to be expected from genetic drift alone, suggesting a possible adaptive basis for the observed differentiation. In fact, avian predation pressure and several physiochemical environmental variables were identified as the main putative drivers of the observed differentiation, particularly in the dorsal spines, ascending process and lateral plates. Hence, the high degree of morphometric differentiation among Adriatic three‐spined stickleback populations appears to reflect adaptation to local ecological conditions. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 115 , 219–240.     

Microsatellite markers indicate genetic differences between cultivated and natural populations of endangered Taxus yunnanensis

Taxus yunnanensis (Taxaceae) is an endangered plant known for its effective natural anti‐cancer metabolite, taxol. To assess the effectiveness of T. yunnanensis ex situ conservation in China, the genetic diversity and genetic structure of nine cultivated and 14 natural populations were compared using 11 polymorphic microsatellite markers. The purpose of this comparison was to determine whether the cultivated populations were genetic representatives of natural types. Among the 14 natural populations studied, three were from Tibet and 11 were from the Hengduan Mountains. There were fewer genetic variations among cultivated populations than among natural populations, but this difference was not significant. However, 23 unique alleles were detected in cultivated populations and 14 were detected in natural populations. Striking differences in genetic structure (G_ST = 0.365) was observed between them. STRUCTURE, AMOVA and cluster analyses also consistently showed a clear genetic separation between the 14 natural and seven cultivated populations. Only five natural populations from the south‐central Hengduan Mountains were genetically represented in two cultivated collections. The reason for the occurrence of distinct genetic differences between cultivated and natural populations and the loss of natural population‐specific alleles in the cultivated populations can be attributed to uneven selection during establishment. These results suggest that the genetic structure of T. yunnanensis may not have been conserved effectively. Based on our study, practical conservation strategies for ex situ preservation of T. yunnanensis have been developed. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 177 , 450–461.     

Diversity and genetic structure of three species of Dioon Lindl. (Zamiaceae, Cycadales) from the Pacific seaboard of Mexico

We have estimated levels of genetic diversity and partitioning in the Mexican endemic cycad species Dioon sonorense, Dioon tomasellii, and Dioon holmgrenii, whose populations are exclusively distributed along the Pacific seaboard. For the three species, the patterns of variation at 19 allozyme loci in a total of 11 populations were evaluated. The average number of alleles per locus was in the range 2.05–1.68, corresponding to the northernmost population of D. sonorense (Mazatán), and the southernmost population of Dioon holmgrenii (Loxicha), respectively. In turn, the percentage of polymorphic loci peaked (94.73) in the El Higueral and Altamirano populations of Dioon tomasellii, and was estimated to be lowest (57.89) in the Loxicha population of D. holmgrenii. The mean expected heterozygosis varied markedly between taxa, with relatively high indices for D. sonorense and D. tomasellii (H_E = 0.314 and 0.295, respectively) and substantially lower values for D. holmgrenii (H_E = 0.170). Comparison of the inferred genetic structure based on F‐statistics for the three species also indicated differences along the north‐south Pacific seaboard axis. For D. sonorense and D. tomasellii, local inbreeding (F_IS) was zero but global inbreeding (F_IT) values were positive and significantly different from zero (0.130 and 0.116, respectively). By contrast, values of both F_IT and F_IS were negative and significantly different from zero (?0.116 and ?0.201, respectively) for D. holmgrenii. The genetic differentiation between populations (F_ST) had positive values in all taxa and corresponded with their geographic location along the north‐south axis: according to this statistic, D. sonorense was the most differentiated species (F_ST = 0.151), D. tomasellii had intermediate values (F_ST = 0.145), and D. holmgrenii was the less differentiated taxon (F_ST = 0.069). Finally, a phenogram representing Nei's genetic distances among populations displayed three major groups, each one corresponding to each of the studied species. Within D. tomasellii (of intermediate geographic distribution), a further division into two clusters corresponded precisely to the pair of populations that are geographically divided by the Trans Mexican Neovolcanic Mountains. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 94 , 765–776.     

Population genetic structure and a possible role for selection in driving phenotypic divergence in a rainbowfish (Melanotaeniidae)

Quantitative genetic divergence may be driven by drift or selection. The rainbowfish Melanotaenia australis exhibits phenotypic divergence among populations in Western Australia, although the mechanisms driving this divergence are unknown. We used microsatellites to assess neutral genetic divergence (F_ST), and found a hierarchical pattern of subdivision consistent with low divergence between upstream and downstream populations (within drainages), moderate divergence between drainages (within regions), and high divergence between regions. Using a common‐garden approach, we measured quantitative genetic divergence in phenotypic traits (Q_ST). By comparing this to expectations from neutral processes (F_ST), we concluded that the effect of selection varies depending on the spatial scale considered. Within drainages, selection may be causing divergence between upstream and downstream phenotypes but, between regions, selection appears to homogenize phenotypes. This highlights the importance of spatial scale in studies of this kind, and suggests that, because variance in selection pressures can drive speciation, polymorphism in M. australis may represent speciation in action. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 144–160.     

Phylogeography and species limits in the green woodpecker complex (Aves: Picidae): multiple Pleistocene refugia and range expansion across Europe and the Near East

The green woodpecker complex consists of the green woodpecker (Picus viridis), distributed from Western Europe to the Caucasus and Iran, and the related LeVaillant's woodpecker (P. vaillantii), distributed in north‐western Africa from central Morocco to Tunisia. Much of the habitat of green woodpeckers in Central and Northern Europe was covered by ice, tundra, steppe or other unsuitable habitat during the Pleistocene; consequently, they must have come to occupy most of their current range during the past 20 000 years. We used complete mitochondrial ND2 sequences from populations throughout the range to investigate the genetic structure and evolutionary history of this complex. Three well‐differentiated clades, corresponding to three biogeographical regions, were recovered; 89% of the total genetic variance was distributed among these three regions. The populations in North Africa were sister to those of Europe and, within Europe, Iberia was sister to the rest of Europe and the Near East. This suggests that the post‐glacial colonization of most of Europe occurred from a refuge east of Iberia, probably in Italy or the Balkans; there was no substantial divergence among these regions. In addition, a population sample from Iran was genetically distinct from those of Western Europe, indicating a history of genetic isolation and an additional Pleistocene refuge east of the well‐known Balkan refugia and south of the Caucasus. Within Europe, northern populations were less genetically variable than southern ones, consistent with recent colonization. There was significant isolation‐by‐distance across Europe, indicating restricted gene flow; this was particularly apparent between western populations and those of the Caucasus and Iran. We recognize four species in the complex. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 104 , 710–723.     

East–west genetic differentiation in Musk Ducks (<Emphasis Type="Italic">Biziura lobata</Emphasis>) of Australia suggests late Pleistocene divergence at the Nullarbor Plain

Musk Ducks (Biziura lobata) are endemic to Australia and occur as two geographically isolated populations separated by the Nullarbor Plain, a vast arid region in southern Australia. We studied genetic variation in Musk Duck populations at coarse (eastern versus western Australia) and fine scales (four sites within eastern Australia). We found significant genetic structure between eastern and western Australia in the mtDNA control region (Φ_ST = 0.747), one nuclear intron (Φ_ST = 0.193) and eight microsatellite loci (F_ST = 0.035). In contrast, there was little genetic structure between Kangaroo Island and adjacent mainland regions within eastern Australia. One small population of Musk Ducks in Victoria (Lake Wendouree) differed from both Kangaroo Island and the remainder of mainland eastern Australia, possibly due to genetic drift exacerbated by inbreeding and small population size. The observed low pairwise distance between the eastern and western mtDNA lineages (0.36%) suggests that they diverged near the end of the Pleistocene, a period characterised by frequent shifts between wet and arid conditions in central Australia. Our genetic results corroborate the display call divergence and Mathews’ (Austral Avian Record 2:83–107, 1914) subspecies classification, and confirm that eastern and western populations of Musk Duck are currently isolated from each other.     

Genetic differentiation and intraspecific structure of Eastern Tropical Pacific spotted dolphins,Stenella attenuata,revealed by DNA analyses

Mitochondrial DNA (mtDNA) control region sequences and microsatellite loci length polymorphisms were used to investigate genetic differentiation in spotted dolphins (Stenella attenuata) in the Eastern Tropical Pacific and to examine the intraspecific structure of the coastal subspecies (Stenella attenuata graffmani). One-hundred and thirty-five animals from several coastal areas and 90 offshore animals were sequenced for 455 bp of the mitochondrial control region, resulting in 112 mtDNA haplotypes. Phylogenetic analyses and the existence of shared haplotypes between the two subspecies suggest recent and/or current gene flow. Analyses using χ², F _ST (based on haplotype frequencies) and Φ_ST values (based on frequencies and genetic distances between haplotypes) yielded statistically significant separation (randomized permutation values P<0.05) among four different coastal populations and between all but one of these and the offshore subspecies (overall F _ST=0.0691). Ninety-one coastal animals from these four geographic populations and 50 offshore animals were genotyped for seven nuclear microsatellite loci. Analysis using F _ST values (based on allelic frequencies) yielded statistically significant separation between most coastal populations and offshore animals, although no coastal populations were distinguished. These results argue for the existence of some genetic isolation between offshore and inshore populations and among some inshore populations, suggesting that these should be treated as separate units for management purposes.     

Very fine‐scale population genetic structure of sympatric asterinid sea stars with benthic and pelagic larvae: influence of mating system and dispersal potential

The present study investigated the fine‐scale population genetic structure of sympatric asterinid sea stars with contrasting modes of larval development (benthic versus pelagic). Parvulastra exigua lacks a dispersive life phase yet is one of the worlds most widely distributed and abundant sea stars, whereas Meridiastra calcar, a sea star with a dispersive larva, has a more limited regional scale distribution. Populations of P. exigua sampled from tide pools on three adjacent headlands showed significant genetic substructure (mitochodrial DNA control region) at fine spatial scales (tide pools < 300 m apart: F_ST = 0.249, P < 0.01; headlands 5–15 km apart: F_ST = 0.125, P = 0.04). As expected, M. calcar populations sampled from the same headlands did not exhibit significant genetic structuring (F_ST = 0.029, P = 0.14). The life‐history traits of P. exigua, a mixed mating system (selfing + outcrossing), pseudocopulation among closely‐related conspecifics, and an entirely benthic life cycle with a philopatric larva, undoubtedly influence its strong genetic structure across fine spatial scales. Localized genetic structure, especially at the very fine‐scale of tide pools, would not be detected in the more typical regional scale approaches adopted by most studies of marine invertebrate populations. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, ●●, ●●–●●.     

Species‐level view of population structure and gene flow for a critically endangered primate (Varecia variegata)

Lemurs are among the world's most threatened mammals. The critically endangered black‐and‐white ruffed lemur (Varecia variegata), in particular, has recently experienced rapid population declines due to habitat loss, ecological sensitivities to habitat degradation, and extensive human hunting pressure. Despite this, a recent study indicates that ruffed lemurs retain among the highest levels of genetic diversity for primates. Identifying how this diversity is apportioned and whether gene flow is maintained among remnant populations will help to diagnose and target conservation priorities. We sampled 209 individuals from 19 sites throughout the remaining V. variegata range. We used 10 polymorphic microsatellite loci and ~550 bp of mtDNA sequence data to evaluate genetic structure and population dynamics, including dispersal patterns and recent population declines. Bayesian cluster analyses identified two distinct genetic clusters, which optimally partitioned data into populations occurring on either side of the Mangoro River. Localities north of the Mangoro were characterized by greater genetic diversity, greater gene flow (lower genetic differentiation) and higher mtDNA haplotype and nucleotide diversity than those in the south. Despite this, genetic differentiation across all sites was high, as indicated by high average F_ST (0.247) and Φ_ST (0.544), and followed a pattern of isolation‐by‐distance. We use these results to suggest future conservation strategies that include an effort to maintain genetic diversity in the north and restore connectivity in the south. We also note the discordance between patterns of genetic differentiation and current subspecies taxonomy, and encourage a re‐evaluation of conservation management units moving forward.     

Contrasting patterns of genetic differentiation in Macaronesian lineages of Ilex (Aquifoliaceae)

Islands offer an interesting framework in which to study the effect of geographical isolation on population genetic differentiation. For plant species with high dispersal abilities, however, oceanic barriers may not represent a factor promoting strong population structure. In this work, we analysed seven nuclear microsatellite loci in Ilex (Aquifoliaceae), a bird‐dispersed plant group, to infer patterns of genetic differentiation among Macaronesian taxa: I. canariensis, I. perado ssp. lopezlilloi, I. perado ssp. platyphylla (Canary Islands) and I. perado ssp. azorica (Azores). In agreement with current taxonomic classification, our results revealed a high genetic differentiation between Ilex lineages (I. canariensis and the I. perado complex), and also supported previous hypotheses that these are the result of independent dispersal events to the islands. In contrast, genetic differentiation between I. perado ssp. azorica and the two subspecies from the Canaries was high, suggesting that taxonomic revision may be necessary. Levels of genetic variation at microsatellite loci in ssp. azorica were, in addition, the lowest reported among Macaronesian bird‐dispersed taxa. Lastly, low genetic differentiation was observed between subspecies occurring on the same island (sspp. platyphylla and lopezlilloi). In summary, our results revealed contrasting patterns between Macaronesian Ilex lineages: I. canariensis displayed moderate population structure across islands, whereas the I. perado complex showed strong differentiation among populations sampled on different islands. Thus, the Macaronesian Ilex taxa show that long‐distance dispersal syndromes (ornithochory) do not always ensure genetic connectivity across large areas in island systems. Plant groups that successfully colonized the islands on multiple occasions may have found barriers to gene flow within certain lineages. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 173 , 258–268.     

Is life history a barrier to dispersal? Contrasting patterns of genetic differentiation along an oceanographically complex coast

Extreme variation in early life‐history strategies is considered a moderately good predictor of genetic subdivision and hence dispersal for a range of marine species. In reality, however, a good deal of population differentiation must reflect historical effects, more subtle variation in life histories, and, particularly, the interaction of larvae with oceanographic processes. Using a combination of allozyme and microsatellite markers, we show that the large‐scale genetic structure of populations of three species (direct and planktonically developing cushion stars and a planktonic developing sea anemone that is also asexually viviparous) varies consistently, in line with the predicted capacity for dispersal within three geographic regions. We detected high levels of genetic subdivision for the direct developing cushion star (F_ST = 0.6), low levels for the planktonically developing cushion star (F_ST = 0.009), and intermediate levels for the sexual/asexual sea anmone (F_ST = 0.19). These patterns are exhibited despite the highly variable patterns of current movement and the presence of biogeographic barriers. Our results suggest that, although there is large scale genetic differentiation for two species, patterns of population connectivity are remarkably consistent within major regions and do not reflect variation in major oceanographic processes or genetic discontinuity coincident with biogeographic boundaries. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95 , 106–116.