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We explored the reproductive modes of Viva intestinalis in the inner part of the Baltic Sea during three consecutive years by using five microsatellite loci to estimate the relative abundance of diploid sporophytes and haploid gametophytes. Our results suggest that both diploid sporophytes and haploid gametophytes occur regularly in the Baltic Sea. The ratio of haploid to diploid individuals changes with seasons. Sporophytes are more abundant than gametophytes throughout the year, but the proportion of haploids increases from 10% in early summer to 35% in September. The over-wintering takes primarily place as diploid spores released by sporophytes. The sporophytes appear to reproduce both sexually and asexually in the Baltic Sea, since clones were found for this life phase. The fraction of individuals which belonged to an apparent diploid clone was higher in spring (62%) than in autumn (33%). We also found evidence for asexual clones in haploid gametophytes. The presence of both diploid and haploid individuals and the pattern of genetic and genotypic diversity provide evidence of sexual reproduction in the Baltic Sea. Thus the sporophytes and gametophytes do not function as two reproductively separate units. Compared with many other algal species with a reduced reproductive cycle in low salinity, U. intestinalis differs by having a multitude of reproductive modes also in the brackish water Baltic Sea, which can in part explain the dynamic propagation and high adaptability of the species.

BACKGROUND: Salix (willow) and Populus (poplar) are members of the Salicaceae family and they share many ecological as well as genetic and genomic characteristics. The interest of using willow for biomass production is growing, which has resulted in increased pressure on breeding of high yielding and resistant clones adapted to different environments. The main purpose of this work was to develop dense genetic linkage maps for mapping of traits related to yield and resistance in willow. We used the Populus trichocarpa genome to extract evenly spaced markers and mapped the orthologous loci in the willow genome. The marker positions in the two genomes were used to study genome evolution since the divergence of the two lineages some 45 mya. RESULTS: We constructed two linkage maps covering the 19 linkage groups in willow. The most detailed consensus map, S1, contains 495 markers with a total genetic distance of 2477 cM and an average distance of 5.0 cM between the markers. The S3 consensus map contains 221 markers and has a total genetic distance of 1793 cM and an average distance of 8.1 cM between the markers. We found high degree of synteny and gene order conservation between willow and poplar. There is however evidence for two major interchromosomal rearrangements involving poplar LG I and XVI and willow LG Ib, suggesting a fission or a fusion in one of the lineages, as well as five intrachromosomal inversions. The number of silent substitutions were three times lower (median: 0.12) between orthologs than between paralogs (median: 0.37 - 0.41). CONCLUSIONS: The relatively slow rates of genomic change between willow and poplar mean that the genomic resources in poplar will be most useful in genomic research in willow, such as identifying genes underlying QTLs of important traits. Our data suggest that the whole-genome duplication occurred long before the divergence of the two genera, events which have until now been regarded as contemporary. Estimated silent substitution rates were 1.28 x 10-9 and 1.68 x 10-9 per site and year, which are close to rates found in other perennials but much lower than rates in annuals.

Dispersal between habitat patches may be important for the long-term persistence of populations. We conducted a mark-release-recapture study and analysed the dispersal pattern in the scarce heath butterfly inhabiting a network of suitable habitat patches using stepwise logistic regression (SLR) and the Virtual Migration (VM) model. We also analysed the influence of different types of matrices. We found that the majority of the recaptured butterflies remained within the patch where they were originally caught. However, dispersal between patches did occur and both the SLR analysis and the VM model indicated that the migration pattern was significantly associated with patch area and its level of isolation. The SLR model also showed that there was a positive association between immigration rate and tree density, supporting earlier observations that this species prefers semi-open habitat. We discuss the use of SLR versus the VM model to analyse recapture data in dispersal studies. This system is not at equilibrium, as a number of the most important patches in the network are continuously being lost due to afforestation and a number of populations are facing deterministic extinction. This increases the risk of a chain reaction of local extinctions, which may cause a collapse of the whole system.

The Scandinavian wolf population represents one of the genetically most well-characterized examples of a severely bottlenecked natural population (with only two founders), and of how the addition of new genetic material (one immigrant) can at least temporarily provide a 'genetic rescue'. However, inbreeding depression has been observed in this population and in the absence of additional immigrants, its long-term viability is questioned. To study the effects of inbreeding and selection on genomic diversity, we performed a genomic scan with approximately 250 microsatellite markers distributed across all autosomes and the X chromosome. We found linkage disequilibrium (LD) that extended up to distances of 50 Mb, exceeding that of most outbreeding species studied thus far. LD was particularly pronounced on the X chromosome. Overall levels of observed genomic heterozygosity did not deviate significantly from simulations based on known population history, giving no support for a general selection for heterozygotes. However, we found evidence supporting balancing selection at a number of loci and also evidence suggesting directional selection at other loci. For markers on chromosome 23, the signal of selection was particularly strong, indicating that purifying selection against deleterious alleles may have occurred even in this very small population. These data suggest that population genomics allows the exploration of the effects of neutral and non-neutral evolution on a finer scale than what has previously been possible.

The Myristicaceae family is a primitive angiosperm family and is characterized by species that are highly endemic to the Western Ghats area of India. Myristica malabarica is confined to the evergreen forests of Western Ghats and Sri Lanka. In this paper we describe for the first time the development of eleven polymorhpic microsatellite markers for Myristica malabarica, which had 2–14 alleles per locus. These microsatellite markers could be used to study the population genetic structure of the species.

Dysoxylum malabaricum Bedd. (Meliaceae) is an economically important tree species occurring in the Western Ghats, a mega-diversity hotspot in southern India. In this paper, we report the development of fifteen microsatellite markers for D. malabaricum. The microsatellite primers development of fifteen microsatellite markers for D. malabaricum. The microsatellite primers screened had 2-9 alleles per locus and the observed and expected heterozygosity ranged from 0.07 to 1.00 and 0.07 to 0.9 respectively. Seven microsatellites cross amplified in the related species Dysoxylum binectariferum and showed good polymorphism. These are the first microsatellites described for D. malabaricum and they will be used to study population structure and genetic diversity.

We have recently found that the morphologically determined subspecies Gymnadenia conopsea ssp conopsea in Sweden includes early and late flowering individuals. We were interested in the interactions between the flowering time groups; if there were gene flow between them and if so this was detrimental or advantageous. A spatially mixed population of early and late flowering individuals was studied using three microsatellite loci. We measured patterns in genetic differentiation and inferred occurrence of hybridisation and introgression. Variation in flowering time, fertility and relative and absolute fruit set was measured. The pattern of introgression between flowering-time groups differed between loci. In two of the three investigated loci, allele separation was distinct between early and late flowering plants and one genetically obvious hybrid was infertile. In the third locus, several alleles were shared between the two flowering time variants. The degree of introgression was associated to fruit set failure, which was higher in the late flowering plants and lower in early flowering plants. A small group of early flowering individuals with somewhat delayed flowering compared to the main group was genetically distinct and had lower relative and absolute fruit set. This group was not genetically intermediate, but rather constituting an independent group, with lower fruit set possibly caused by absence of pollinators. There seem to be a strong barrier against introgression into the late flowering group which is kept genetically distinct and less diverse. The early flowering group is diverse, includes two subgroups and seems to benefit from gene flow.

In small and declining populations levels of genetic variability are expected to be reduced due to effects of inbreeding and random genetic drift. As a result, both individual fitness and populations' adaptability can be compromised, and the probability of extinction increased. Therefore, maintenance of genetic variability is a crucial goal in conservation biology. Here we show that although the level of genetic variability in mtDNA of the endangered Fennoscandian lesser white-fronted goose Anser erythropus population is currently lower than in the neigbouring populations, it has increased sixfold during the past 140 years despite the precipitously declining population. The explanation for increased genetic diversity in Fennoscandia appears to be recent spontaneous increase in male immigration rate equalling 0.56 per generation. This inference is supported by data on nuclear microsatellite markers, the latter of which show that the current and the historical Fennoscandian populations are significantly differentiated (F-ST = 0.046, P = 0) due to changes in allele frequencies. The effect of male-mediated gene flow is potentially dichotomous. On the one hand it may rescue the Fennoscandian lesser white-fronted goose from loss of genetic variability, but on the other hand, it eradicates the original genetic characteristics of this population.

Aim The main aim of the present study is to infer the post-glacial history of Abies species from north-east Asia and to test the hypotheses that coastal Abies populations suffered less from climatic fluctuations during Pleistocene glacial periods than their more continental counterparts, and that Sakhalin was a major area of introgression. Location Natural ranges of the fir species Abies nephrolepis, Abies sachalinensis and Abies holophylla in the Russian Far East, and of Abies gracilis, which is endemic to the Kamchatka Peninsula. Methods Nineteen populations were sampled for allozyme analysis. Seventeen of these populations were also screened for variation at two paternally inherited chloroplast DNA microsatellite loci (cpSSR) and variation at one maternally inherited mitochondrial marker (nad4-3/4). Finally a subset of 11 populations was analysed with amplified fragment length polymorphism (AFLP). Comparisons were made with already available Abies sibirica data. For all sets of markers, we estimated genetic diversity and differentiation using an analysis of molecular variance (AMOVA). Population clustering was assessed with a Bayesian approach implemented in structure v.2.3. Results Among the three major species, A. sibirica, A. nephrolepis and A. sachalinensis, A. sachalinensis demonstrated the highest cytoplasmic and nuclear diversity and the most continental species, A. sibirica, the lowest. Both nuclear and mitochondrial DNA markers revealed the presence of a transitional zone on Sakhalin Island between A. nephrolepis and A. sachalinensis of south Sakhalin. The structure analysis delivered very clear results confirming the admixed origin of A. sachalinensis, with a genetic contribution from A. nephrolepis. No variation in cytoplasmic markers was found in A. gracilis, suggesting the occurrence of a recent bottleneck. Main conclusions There is a clear reduction of genetic diversity in Abies species from the Pacific coast into the continent. The higher diversity in A. sachalinensis could have two causes: a larger effective population size in the islands due to relatively stable climatic conditions and consequently less pronounced demographic fluctuations in population size and/or hybridization with continental and Japanese populations. Sakhalin Island is a major transitional zone for conifer species. Finally, the fir from Kamchatka, A. gracilis, should be regarded as a separate species closely related to the A. nephrolepis-A. sachalinensis complex.

We used DNA microsatellites to study colony kin structure and breeding patterns in the primitively eusocial wasp Polistes biglumis. P. biglumis inhabits cool areas at high altitudes and, as a consequence, has a reduced colony cycle compared to more temperate Polistes. P. biglumis colonies are always founded and controlled by a single foundress, but nest failure is common and foundresses losing their nests do not have time to start new ones due to the short season. Instead, nests are characterized by frequent female turnover, in the form of females taking over (usurpation) other con-specific nests. Our results showed that most nests had offspring from multiple unrelated females, including some where multiple females were not observed in monitoring. Reconstruction of behavioural events from the genetic data revealed three types of multiple matriline nests: (a) nests that were usurped by another female, where the original nest owner disappeared following the usurpation event, (b) nests that were joined by another female, where the original nest owner stayed following the joining event, (c) nests that were both usurped and joined by other females. We also found, for the first time, a clear indication of multiple mating by Polistes females. Moreover, males mating with the same female were related, which may be explained by the lek mating system of P. biglumis. Finally, we analysed the nest sex ratios and how it changed during the season and found that sexes were produced sequentially, males before females.