Within-population Genetic Diversity Research Articles

Regional population structure of the endangered Bridle Shiner (Notropis bifrenatus)

In the last 100 years, the Bridle Shiner has declined over significant parts of its range. We used mitochondrial and nuclear microsatellite markers to investigate population structure of this species. Tissue samples were collected from populations in six drainages in PA, NJ, NY and CT. One predominant haplotype was observed in the Delaware, Housatonic, Passaic, and Raritan specimens. Specimens from the Hudson and St. Lawrence drainages had a separate unique haplotype. Microsatellite loci revealed low within-population genetic diversity and pairwise population comparisons of allelic divergence showed significant genetic differences among most drainages. Population structure analysis of microsatellite loci recover the same population clusters inferred using mtDNA. Within the Delaware drainage, there was significant differentiation among areas separated by 128 km. Several alternate scenarios of population divergence and population bottlenecks were investigated using approximate Bayesian computing. These supported a scenario with a bottleneck occurring in the ancestral population of Bridle Shiner followed by recent divergence of Northern and Southern drainages.

Genetic diversity and structure of a rare endemic cactus and an assessment of its genetic relationship with a more common congener.

Endemic, obligate outcrossing plant species with narrow geographic distributions and disjunct populations are prone to loss of genetic diversity. Simultaneously, delineating clear species boundaries is important for targeted conservation efforts. The rare and endemic cactus, Sclerocactus brevihamatus subsp. tobuschii (SBT), has a parapatric relationship with Sclerocactus brevihamatus subsp. brevihamatus (SBB) but genetic distance between the two taxa is unknown. We: (1) developed taxon-specific polymorphic microsatellites, (2) assessed genetic diversity within and among nine populations of SBT, and within one population of SBB, and (3) estimated the genetic relationship between the two subspecies. Within-population genetic diversity of SBT was moderate to high (mean Ho = 0.37; mean He = 0.59). Indirect estimate of inbreeding corrected for null alleles (Fis-INEst) was low for SBT, ranging from 0.03 to 0.14 (mean Fis-INEst = 0.07). Genetic differentiation among populations of SBT was low based on Fst (0.08) and AMOVA (ФPT = 0.10). Lack of genetic and spatial correlation in SBT populations coupled with the presence of private alleles and bottleneck events in several populations suggests that reproductive isolation is occurring but that sufficient time may not have yet passed to manifest strong differentiation. Cluster analyses segregated the 10 populations into three distinct groups, and separated SBB genotypes clearly. Results suggest that while hybridization between the two subspecies may occur, SBT is clearly differentiated genetically from SBB to retain its current taxonomic status.

Genetic diversity and demographic history of the Siberian lime (Tilia sibirica)

Tilia sibirica Bayer (Siberian lime) is endemic to the low mountain systems north of the Altai Mountains of southern Siberia, approximately 1,000 kms to the east of the natural range limit of its closest congeneric, the small-leaved lime (Tilia cordata). Some consider the taxon to be a subspecies of T. cordata. This putative pre-Last Glacial Maximum (LGM) relict may have had a stronghold in a refugium of the Altai Mountains and survived various waves of fluctuating climatic changes that occurred in the region. With continued climatic changes expected, these hardy but isolated populations can be important sources for population expansion. To date, we do not know the genetic status or history of this forest tree.This study uses standard population genetic and Approximate Bayesian Computation (ABC) analyses of microsatellite data to determine the genetic diversity and differentiation, clonal occurrence and date of divergence of the two lime taxa. The results show that T. sibirica and T. cordata are distinct biological units with significant genetic differentiation. The ABC analysis suggests a (Middle) Pleistocene divergence. We have revealed low within-population genetic diversity as well as high levels of clonality in T. sibirica. The focus now should be on restoring and conserving these small and isolated relict populations.

Genetic diversity in the endangered terrestrial orchid Cypripedium japonicum in East Asia: Insights into population history and implications for conservation

Little is known about levels and patterns of genetic diversity for the entire range of endangered orchids native to China, Korea, and Japan. In this study, we focus on Cypripedium japonicum and suggest three hypotheses: 1) that genetic drift has been a primary evolutionary force; 2) that populations in central and western China harbor higher levels of genetic variation relative to those from eastern China; and 3) that C. japonicum in China maintains the highest genetic variation among the three countries. Using ISSR and SCoT markers, we investigated genetic diversity in 17 populations to test the three hypotheses. As anticipated, we found low levels of genetic diversity at the species level with substantially high degree of genetic divergence, which can be mainly attributed to random genetic drift. Chinese populations harbor the highest within-population genetic variation, which tends to increase from east to west. We also found a close relationship between Korean populations and central/western Chinese populations. Historical rarity coupled with limited gene flow seems to be important factors for shaping genetic diversity and structure of C. japonicum. Our results indicate that the mountain areas in central and western China were likely refugia at the Last Glacial Maximum.

Rapid selection of sulphadoxine-resistant Plasmodium falciparum and its effect on within-population genetic diversity in Papua New Guinea

The ability of the human malarial parasite Plasmodium falciparum to adapt to environmental changes depends considerably on its ability to maintain within-population genetic variation. Strong selection, consequent to widespread antimalarial drug usage, occasionally elicits a rapid expansion of drug-resistant isolates, which can act as founders. To investigate whether this phenomenon induces a loss of within-population genetic variation, we performed a population genetic analysis on 302 P. falciparum cases detected during two cross-sectional surveys in 2002/2003, just after the official introduction of sulphadoxine/pyrimethamine as a first-line treatment, and again in 2010/2011, in highly endemic areas in Papua New Guinea. We found that a single-origin sulphadoxine-resistant parasite isolate rapidly increased from 0% in 2002/2003 to 54% in 2010 and 84% in 2011. However, a considerable number of pairs exhibited random associations among 10 neutral microsatellite markers located in various chromosomes, suggesting that outcrossing effectively reduced non-random associations, albeit at a low average multiplicity of infection (1.35–1.52). Within-population genetic diversity was maintained throughout the study period. This indicates that the parasites maintained within-population variation, even after a clonal expansion of drug-resistant parasites. Outcrossing played a role in the preservation of within-population genetic diversity despite low levels of multiplicity of infection.

Historical domestication-driven population expansion of the dung beetle Gymnopleurus mopsus (Coleoptera: Scarabaeidae) from its last refuge in Mongolia

Populations of Gymnopleurus mopsus (family Scarabaeidae), a dung beetle that displays dung-rolling behavior (i.e., a telecoprid), have recently experienced sharp declines, and many populations are now at high risk of local extinction. However, Mongolia, which constitutes a major portion of the species’ distribution, still sustains a relatively large population. Here, we used mitochondrial COI sequences to investigate the within-population genetic diversity and both the genetic and phylogeographic structures of 24 G. mopsus populations across the species’ main distribution in Mongolia. Several lines of evidence indicated that the phylogeographic structure of G. mopsus had been influenced by a recent and sudden demographic expansion. Interestingly, the expansion of Mongolia’s G. mopsus population corresponded to the advent of livestock domestication in the region, and the species’ genetic structure coincided with road networks, which presumably serve as migration routes for livestock that might mediate the beetle’s dispersal. In addition, we also found that G. mopsus possesses high levels of haplotype diversity, which is generally indicative of large effective population sizes (Ne). Overall, the present study contributes to the current understanding of G. mopsus’ demographic history and dispersal patterns and also provides valuable information for the species’ conservation and management.

Clonal diversity and genetic structure of Enhalus acoroides populations along Hainan Island, China.

Seagrasses are monocotyledons that grow in intertidal and subtidal zones. Seagrass beds are among ecosystems with the highest ecosystem service value. However, seagrass beds are rapidly decline due to anthropogenic disturbances and global climate change. Enhalus acoroides, a monoecious perennial species, is the largest seagrass in stature. It distributes in tropical regions, with Hainan Island as its northern limits. Clonal diversity and genetic structure of E. acoroides populations in Hainan Island were studied to facilitate its conservation and restoration. We used four polymorphic microsatellites to genotype samples collected from four extant populations. We found low clonal and genetic diversities within populations, consistent with the expectations of genetic structure in edge populations. A large range of genetic differentiation was found between these four populations, probably due to the large range of geographic distances between them and genetic drift by local extinction and recolonization. We found no sign of recent bottlenecks in all the populations, probably due to the within-population genetic diversity being too low to show obvious reduction even after bottlenecks. We proposed suggestions on population conservation for those with high priority. Given that seagrass bed had experienced rapid decline in recent years, strengthened conservation and ecological restoration are urgently needed.

Migrations of Rodents in the Zone of Local Radioactive Contamination at Different Phases of Population Dynamics and Their Consequences

Migrations of rodents in the zone of local radioactive contamination (East Urals Radioactive Trace, Southern Urals) at different phases of population dynamics are analyzed for the first time. The absence of any isolation of the rodents in the zone of this radioactive trace is convincingly demonstrated and the migration distances are estimated. As is shown, migration decreases the probability for transfer and fixation of adaptations in the chain of generations in vagile rodent species and increases the within-population genetic diversity of animals in adjacent regions. The need to consider the migration factor in a wide range of studies on assessment of biological effects in the zones of local technogenic contamination is confirmed.

Fine-scale genetic structure in populations of the spring ephemeral herb Megaleranthis saniculifolia (Ranunculaceae)

Fine-scale genetic structure (FSGS) in plants occurs primarily through restricted seed dispersal. Analyses of FSGS have been used retrospectively to infer seed dispersal and other ecological processes. The spring ephemeral Megaleranthis saniculifolia, endemic to Korea, is insect-pollinated and has no special seed dispersal mechanism, and its seedling recruitment is quite low. Given these ecological and life-history traits, we expect that there would be significant FSGS in juveniles, which would persist into adult stage. Since M. saniculifolia is self-compatible and many adults produce 2–3 inflorescences, we expect considerable inbreeding. To test these predictions, we used allozyme-based Sp statistics to compare two undisturbed populations on Mt. Deogyu (DEO) and Mt. Taebaek (TAE), as well as between juveniles (J) and adults (A) stages. We also measured genetic diversity and inbreeding in each population. The two populations exhibited significant FSGS in both life stages. Although the strength of FSGS was reduced with increasing stage (J, Sp = 0.0313; A, Sp = 0.0178 in DEO and J, Sp = 0.0502; A, Sp = 0.0286 in TAE), differences in FSGS between stages and between populations were not significant. Within-population genetic diversity (mean %P = 27.0, A = 1.27, He = 0.116) was relatively low and comparable to reference values for both endemic and narrowly-distributed plant species. Genetic differentiation between sites, however, was high (FST = 0.465), and the two populations exhibited a significant deficit of heterozygotes (mean FIS = 0.289), primarily due to selfing and biparental inbreeding (effective selfing rate was ∼0.40). Our results revealed that the magnitude and spatial scale of FSGS in M. saniculifolia is strong and does not differ significantly with life-history stage. The strong FSGS, low within-population genetic variation, high between-population genetic differentiation, and high inbreeding are consistent with the species’ limited seed dispersal and a mixed mating system.

Patterns of Genetic Diversity in Rare and Common Orchids Focusing on the Korean Peninsula: Implications for Conservation

To provide basic information for orchid conservation, we surveyed the plant allozyme literature to summarize genetic diversity and structure data for (i) rare orchids native to the Korean Peninsula, and (ii) their congeners irrespective of being common and rare or Korean or not. A total of 68 taxa (32 taxa in Korea and 37 outside Korea; Goodyera repens being included in both datasets) were considered in this study. Overall, rare Korean orchid species had significantly lower levels of genetic diversity than their common congeners and common orchids in general at both population and species levels. However, mean values of G ST (or F ST) for rare and common orchids (Korean or not) did not differ significantly from each other. We found patterns of both low and high genetic diversity in rare Korean orchids. Many rare orchids harbored a complete lack of allozyme variation or extremely low within-population variation, perhaps due to rarity associated with random genetic drift and/or, for the case of warm-temperate orchids, to founder effects during post-glacial re-colonization. In contrast, high levels of genetic variation were found for a few orchids that have become recently rare (due to over-collection during the past several decades), probably because there have not been sufficient generations for the initial diversity to be substantially eroded. In addition, several orchids occurring in the main mountain system of the Korean Peninsula (the Baekdudaegan), that served as a glacial refugium, maintained moderate to high levels of within-population genetic diversity. Based on our genetic data, conservation priority should be given to rare orchid species. Particularly, urgent measures should be implemented on Jeju Island, a popular vacation spot, because it also a hotspot for threatened orchids with low levels of genetic diversity.

Genetic patterns reflecting Pleistocene range dynamics in the annual calcicole plant Microthlaspi erraticum across its Eurasian range

The range-wide genetic diversity of Microthlaspi erraticum (Brassicaceae), a Eurasian calcareous annual plant, was investigated with respect to its migration and post-glacial re-colonisation of Central Europe. Both AFLP and sequence data (ITS, matK, trnL-F) were used to analyse 85 populations of the species sampled across its range, including Europe and Anatolia as well as the disjunct populations in Central Asia. A substantial portion of the explainable genetic variation was found to be correlated with climatic heterogeneity. A low level of within-population genetic diversity throughout the range, and a clear genetic differentiation among populations is consistent with the mainly selfing nature and fragmented distribution of the species. The highest within-population genetic diversity was found in Central Europe. However, the number of rare and private fragments was substantially higher in southern Europe and Anatolia, the inferred ancestral range of M. erraticum, whereas populations found in Kazakhstan originated from Anatolia, following a profound population bottleneck. The diversity patterns found in Central Europe and migration models support postglacial re-colonisation from two regions; the south-western Alps and the Balkans. Hence, our results provide molecular evidence for a suture zone in Central Europe, where advancing genotypes from different refugia meet and mix.

Distribution and Genetic Structure of Fucus distichus Linnaeus 1953 (formerly F. gardneri) within Central San Francisco Bay

Fucus distichus, a rockweed common to the mid-intertidal shoreline within the San Francisco Estuary (previously known as F. gardneri), was injured during the Cosco Busan oil spill in November 2007 and subsequent clean-up actions. Restoration planning activities are underway to help recover F. distichus at sites within central San Francisco Bay where damage occurred. As a first step, we conducted shoreline surveys during the summers of 2012–2013 to map the occurrence of this rockweed. Of the 151.73 km of rocky shoreline within the central bay, F. distichus covered 32.16 km of shoreline. The alga generally occurred in narrow bands but formed expansive beds at locations with natural, flat bedrock benches. We also observed F. distichus on artificial substrata such as seawalls and riprap, but not on pilings. Samples of F. distichus from 11 sites throughout the central / east San Francisco Bay were genetically analyzed (microsatellite genotyping). The populations analyzed (1) had low genetic diversity, (2) the frequency of homozygotes was higher than expected (suggesting high inbreeding), and (3) also displayed geographic population structure, in part driven by very small differences in the midst of extremely low within-population genetic diversity. However, these genetic data do not raise concerns for restoration methods in terms of choosing donor populations and mixing F. distichus from different sites within the central bay. The choice of donor populations should be based on practical criteria for effective restoration; individuals will nonetheless be taken from locations as nearby to donor sites as possible. Various locations throughout the central San Francisco Bay are composed of cobble or small riprap that are populated with F. distichus, which could provide efficient means of translocating rockweed for future restoration activities.

Potential for adaptation to climate change: family-level variation in fitness-related traits and their responses to heat waves in a snail population

BackgroundOn-going global climate change poses a serious threat for natural populations unless they are able to evolutionarily adapt to changing environmental conditions (e.g. increasing average temperatures, occurrence of extreme weather events). A prerequisite for evolutionary change is within-population heritable genetic variation in traits subject to selection. In relation to climate change, mainly phenological traits as well as heat and desiccation resistance have been examined for such variation. Therefore, it is important to investigate adaptive potential under climate change conditions across a broader range of traits. This is especially true for life-history traits and defences against natural enemies (e.g. parasites) since they influence organisms’ fitness both directly and through species interactions. We examined the adaptive potential of fitness-related traits and their responses to heat waves in a population of a freshwater snail, Lymnaea stagnalis. We estimated family-level variation and covariation in life history (size, reproduction) and constitutive immune defence traits [haemocyte concentration, phenoloxidase (PO)-like activity, antibacterial activity of haemolymph] in snails experimentally exposed to typical (15 °C) and heat wave (25 °C) temperatures. We also assessed variation in the reaction norms of these traits between the treatments.ResultsWe found that at the heat wave temperature, snails were larger and reproduced more, while their immune defence was reduced. Snails showed high family-level variation in all examined traits within both temperature treatments. The only negative genetic correlation (between reproduction and antibacterial activity) appeared at the high temperature. However, we found no family-level variation in the responses of most examined traits to the experimental heat wave (i.e. largely parallel reaction norms between the treatments). Only the reduction of PO-like activity when exposed to the high temperature showed family-level variation, suggesting that the cost of heat waves may be lower for some families and could evolve under selection.ConclusionOur results suggest that there is genetic potential for adaptation within both thermal environments and that trait evolution may not be strongly affected by trade-offs between them. However, rare differences in thermal reaction norms across families indicate limited evolutionary potential in the responses of snails to changing temperatures during extreme weather events.

Genetic structure of gall oak (Quercus infectoria) characterized by nuclear and chloroplast SSR markers

Quercus infectoria, commonly known as gall oak, is a small shrub found in Iran. Unfortunately, it is subjected to genetic erosion, and so, its conservation and evaluation are desirable. Thus, in the current research, 16 microsatellite primer pairs (seven nuclear simple sequence repeats (nSSRs) and nine chloroplast simple sequence repeats (cpSSRs)) were used in an attempt to assess the genetic diversity of 121 individuals of Q. infectoria belonging to 11 populations from three provinces in northern Zagros forests of Iran. In total, 69 alleles of nSSR and 18 alleles of cpSSR were detected among the individuals. The results of the overall analysis of molecular variance based on nSSRs indicated that 89.00% of the variation was due to differences within populations and 11.00% occurred among populations, while according to cpSSRs, 94.00% of the variation resided among populations, and only 6.00% could be attributed to variation within populations. A higher genetic differentiation of Q. infectoria populations was found according to cpSSR data in comparison to nSSR data. Cophenetic correlation coefficient values were statistically insignificant between nSSR and cpSSR data. The unweighted pair group method with arithmetic mean and Bayesian cluster analyses grouped the studied individuals into two main clusters based on both nSSR and cpSSR data. nSSR data could not completely clustered individuals next each other according to their geographical collection area. Information detailed by nSSR loci revealed that north-Zagros gall oak preserves average levels of genetic diversity at the species level, high level of within-population genetic diversity, and moderate level of genetic variation among populations. The present results provide valuable data for in situ or ex situ conservation and utilization of the studied germplasm.

Genetic diversity is largely unpredictable but scales with museum occurrences in a species-rich clade of Australian lizards.

Genetic diversity is a fundamental characteristic of species and is affected by many factors, including mutation rate, population size, life history and demography. To better understand the processes that influence levels of genetic diversity across taxa, we collected genome-wide restriction-associated DNA data from more than 500 individuals spanning 76 nominal species of Australian scincid lizards in the genus Ctenotus To avoid potential biases associated with variation in taxonomic practice across the group, we used coalescent-based species delimitation to delineate 83 species-level lineages within the genus for downstream analyses. We then used these genetic data to infer levels of within-population genetic diversity. Using a phylogenetically informed approach, we tested whether variation in genetic diversity could be explained by population size, environmental heterogeneity or historical demography. We find that the strongest predictor of genetic diversity is a novel proxy for census population size: the number of vouchered occurrences in museum databases. However, museum occurrences only explain a limited proportion of the variance in genetic diversity, suggesting that genetic diversity might be difficult to predict at shallower phylogenetic scales.

Genetic characterization of Brycon hilarii (Characiformes) populations within the Pantanal: Aspects of their conservation within a globally important neotropical wetland

Brycon hilarii, a characid species endemic to the Upper Paraguay hydrographic basin, is important to regional artisanal and sports fisheries. To develop effective strategies for conservation of this species in the face of potential environmental changes in the Pantanal region, we characterized genetic structuring within and among six B. hilarii collections based on variation at five microsatellite DNA markers. Within-population genetic variability was high, with 75 different alleles; mean average allelic richness per locus per sample location ranged from 6.06 to 7.99. Nei’s gene diversity (hs) varied among drainages from 0.66 (±0.2) to 0.69 (±0.2), with an average across the four genetically identified populations of 0.68 (±0.02). Analyses of Jost’s D EST and F ST-like indices, AMOVA, and Structure-based clustering analyses indicated that B. hilarii populations exhibit a low level of genetic structure, with some indications that the Taquari River population is somewhat distinct from others. Results of K-means analysis suggested little or no structuring, with weakly differentiated populations above and below the confluence of the Paraguay and Taquari rivers. Because B. hilarii populations in the Pantanal are linked by high levels of gene flow, habitat alterations that would interfere with gene flow may jeopardize the long-term persistance of the species.

Conservation genetics of the capercaillie in Poland - Delineation of conservation units.

The capercaillie (Tetrao urogallus) is one of Poland's most endangered bird species, with an estimated population of 380–500 individuals in four isolated areas. To study these natural populations in Poland further, more than 900 non-invasive genetic samples were collected, along with samples from 59 birds representing large, continuous populations in Sweden and Russia; and from two centres in Poland breeding capercaillie. Microsatellite polymorphism at nine loci was then analysed to estimate within-population genetic diversity and genetic differentiation among populations. The results confirmed that isolation of populations and recent decreases in their sizes have reduced genetic diversity among capercaillie in Poland, with all the country’s natural populations found to be experiencing the genetic after-effects of demographic bottlenecks. The results of analyses of genetic differentiation and structure further suggest the presence of a 'lowland' cluster (encompassing birds of the Augustowska and Solska Primaeval Forests in Poland, and of Sweden and Russia), and a Carpathian cluster. Capercaillie from Sweden and Russia are also found to differ markedly. The Polish lowland populations seem more closely related to birds from Scandinavia. Our genetic analysis also indicates that the stocks at breeding centres are of a high genetic diversity effectively reflecting the origins of founder individuals, though identification of ancestry requires further study in the case of some birds.Overall, the results sustain the conclusion that the Polish populations of capercaillie from the Carpathians and the lowlands should be treated as independent Management Units (MUs). This is to say that the breeding lines associated with these two sources should be maintained separately at breeding centres. The high level of genetic differentiation of birds from the Solska Primaeval Forest suggests that this population should also be assigned the status of independent MU.

Genetic diversity and genetic structure of the endangered Manchurian trout, Brachymystax lenok tsinlingensis, at its southern range margin: conservation implications for future restoration

The Manchurian trout, Brachymystax lenok tsinlingensis (family: Salmonidae), is a cold freshwater fish endemic to Northeast Asia. South Korean populations of this species, which comprise its southern range limit, have recently decreased markedly in size and are now becoming critically endangered. We assessed the current population status of this species in South Korea by estimating the levels of genetic diversity and genetic structure of five natural and four restored populations using mitochondrial DNA (mtDNA) control region sequences and eight nuclear microsatellite loci. Levels of within-population genetic diversity were low, suggesting that past effective population sizes (N e) have been small. Each population had one or a maximum of two mtDNA haplotypes. Microsatellite allelic richness (AR) was significantly higher for natural populations (mean AR = 3.51; 95% confidence interval, 3.00–4.03) than for restored populations (mean AR = 2.61; 2.38–2.98). South Korean populations were significantly genetically isolated from one another, with private mtDNA haplotypes and microsatellite alleles, suggesting that limited gene flow has been occurring among populations. A mtDNA phylogeny revealed that South Korean lineages were more closely related to those of China than to those of North Korea and Russia. Overall, we suggest that future restoration efforts aimed at South Korean populations should consider the genetic characteristics reported here, which should help to fulfil effective conservation strategies for this highly cherished species. Our results will inform other conservation efforts, including assisted migration of freshwater fish populations at the equatorial end of the geographical range limit of the species.

Quantitative genetic differentiation and phenotypic plasticity of European beech in a heterogeneous landscape: Indications for past climate adaptation

Tree growth and species distributions are expected to be altered by climate change. European beech (Fagus sylvatica), one of the major tree species in Central Europe, is considered to be particularly threatened by the expected changes in local water regimes. Basic knowledge on the species⬢ genetic variation, environmental adaptation, and phenotypic plasticity is required to assess its potential for climate change adaptation, but sufficient information is lacking. Here, we describe a seedling common garden study at two field sites incorporating 77 natural populations of European beech from an environmentally heterogeneous mountain region in the center of its distribution. We aimed to identify patterns of genetic variation and phenotypic plasticity in growth and phenology, and to associate these with seed source environments. Population differentiation was greater for phenology than for growth (Qst=0.18⬜0.32 vs. 0.00⬜0.16), but within-population genetic variation was large for all seedling traits. The phenotype-environment associations indicated adaptive divergence in phenology and growth with respect to temperature and water availability, but not to soil characteristics, latitude, longitude, or topography of the seed source locations. Phenotypic plasticity was detected in growth and leaf duration, the magnitude of which differed among populations with different seed source temperatures. We conclude that seedling phenology is key to temperature and drought adaptation in European beech. Changes in local temperature and water regimes might result in local phenological maladaptation of European beech populations, although within-population genetic variation, gene flow, and phenotypic plasticity might mitigate the negative effects of climate change.

Bajos niveles de variación isoenzimática en las poblaciones sureñas del arbusto endémico de Corea <em>Sophora koreensis (Fabaceae)</em>: implicaciones para su conservación

Se investigó la variación isoenzimática del arbusto raro Sophora koreensis en el condado de Yanggu (Corea del Sur), en el extremo sur de su área de distribución. Para obtener información sobre los procesos ecológicos a nivel del paisaje, se estudiaron dos o tres poblaciones para cada una de las cuatro localidades (en total, 10 poblaciones) en un radio de unos 6 km. Se encontraron bajos niveles de variación genética intra-poblacional (%P = 13,6, A = 1,14 y He = 0,026) y un grado moderado de diferenciación genética entre poblaciones (FST = 0,203). El análisis de la varianza molecular (AMOVA) reveló un porcentaje sustancialmente mayor de variación entre poblaciones dentro cada una de las localidades (17%) que entre localidades (5%). No hubo una relación significativa entre la divergencia genética y el logaritmo de la distancia geográfica entre pares de poblaciones (r = 0,032, P = 0,842). Estos resultados sugieren un flujo genético limitado entre poblaciones dentro de las localidades, además de indicar que la mejor estrategia para la preservación de la diversidad genética de S. koreensis es la conservación del máximo número de poblaciones posible.