Publications (11)24.51 Total impact
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Dataset: scalfi et al TAG 2004 errata
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Dataset: Piotti et al Heredity 2009
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Article: Conservation genetics of small relic populations of silver fir (Abies alba Mill.) in the northern Apennines
Plant Biosystems 09/2010; 144(3):683-691. · 1.42 Impact Factor -
Article: Spruce colonization at treeline: where do those seeds come from?
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ABSTRACT: At treeline, selection by harsh environmental conditions sets an upward limit to arboreal vegetation. Increasing temperatures and the decline of traditional animal raising have favoured an upward shift of treeline in the last decades. These circumstances create a unique opportunity to study the balance of the main forces (selection and gene flow) that drive tree migration. We conducted a parentage analysis sampling and genotyping with five microsatellite markers in all Norway spruce individuals (342 juveniles and 23 adults) found in a recently colonized treeline area (Paneveggio forest, Eastern Alps, Italy). Our goal was to evaluate local reproductive success versus gene flow from the outside. We were able to identify both parents among local adults for only 11.1% of the juveniles. In the gamete pool we sampled, two-thirds were not produced locally. Effective seed dispersal distance distribution was characterized by a peak far from the seed source (mean 344.66 m+/-191.02 s.d.). Reproductive success was skewed, with six local adults that generated almost two-thirds (62.4%) of juveniles with local parents. Our findings indicate that, although a few local adults seem to play an important role in the colonization process at treeline, large levels of gene flow from outside were maintained, suggesting that the potential advantages of local adults (such as local adaptation, proximity to the colonization area, phenological synchrony) did not prevent a large gamete immigration.Heredity 05/2009; 103(2):136-45. · 4.60 Impact Factor -
Article: Global change and upward shift of treeline in the Alps: genetic consequences of pastures colonization
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ABSTRACT: In the Alps global warming and change in land use, in particular the drastic reduction in cattle grazing, are causing a progressive treeline ecotone upwards shift. The colonization dynamics of woody species are modulated by high selective pressure on seedlings due to the extreme ecological conditions of this habitat. We studied the colonization dynamics of Norway spruce in a treeline plot, at the upper limit of the Paneveggio forest (Trentino, Italy). We have exhaustively sampled the study stand, collecting needle tissue from all the adults and the juveniles detected, and we have genotyped all the samples (376) with 4 SSR markers. Parentage relationships between the few adults presents in the stand (23) and the juveniles were established. Our results indicate that, in spite of extreme ecological condition of the treeline environment, local adaptations do not seem to favour local parents: only 4% of juveniles have both parents among local adult trees, while 96% of juveniles are completely or partially sired outside the sampling area. Assessing parentage relationship also allowed the estimation of relative reproductive success of local adult trees. Out of a total of 23 adult trees, 5 trees were involved in the 59% of successful reproductive events detected inside the sampling area.Forest@. 01/2007; -
Article: A RAPD, AFLP and SSR linkage map, and QTL analysis in European beech (Fagus sylvatica L.).
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ABSTRACT: The genetic linkage map of European beech ( Fagus sylvatica L.) that we report here is the first to our knowledge. Based on a total of 312 markers (28 RAPDs, 274 AFLPs, 10 SSRs) scored in 143 individuals from a F(1) full-sib family. Two maps (one for each parent) were constructed according to a "two-way pseudo-testcross" mapping strategy. In the male map 119 markers could be clustered in 11 major groups (971 cM), while in the female map 132 markers were distributed in 12 major linkage groups (844 cM). In addition, four and one minor linkage groups (doublets and triplets) were obtained for the male and female map respectively. The two maps cover about 82% and 78% of the genome. Based on the position of 15 AFLP and 2 SSR loci segregating in both parents, seven homologous linkage groups could be identified. In the same pedigree we investigated the association with genetic markers of several quantitative traits: leaf area, leaf number and shape in 2 different years, specific leaf area, leaf carbon-isotope discrimination and tree height. A composite interval-mapping approach was used to estimate the number of QTLs, the amount of variation explained by each of them, and their position on the genetic linkage maps. Eight QTLs associated with leaf traits were found that explained between 15% and 35% of the trait variation, five on the female map and three on the male map.Theoretical and Applied Genetics 03/2004; 108(3):433-41. · 3.30 Impact Factor -
Article: Intraindividual and intraspecies variability of ITS1 sequences in the ancient asexual Darwinula stevensoni (Crustacea: Ostracoda).
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ABSTRACT: The lack of variability in ITS regions within individuals and within species has been explained as the result of concerted evolution. In fact, many examples of intraindividual variation in the ITS regions have been reported. Here we report evidence of within-individual variation of the ITS1 region in the obligate parthenogenetic species Darwinula stevensoni. We analysed 46 clones obtained from 12 individuals of D. stevensoni, from three Italian sites and one site in Luxembourg. Seven nucleotides out of 366 were variable. Most variability (80%) was found among clones within individuals, and the remainder of the variability was observed among individuals. No difference was found among populations or between habitats. The low intraspecific variability and the observation of recombinant molecules are evaluated in light of the relevant literature. The high percentage of variation within individuals and the occurrence of recombination without meiosis are discussed by considering the ancient asexual "status" of the species.Heredity 11/2001; 87(Pt 4):449-55. · 4.60 Impact Factor -
Article: A population ‘consensus’, partial linkage map of Picea abies Karst. based on RAPD markers
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ABSTRACT: We built a “consensus” partial linkage map based on RAPD markers using 48 sibships of eight megagametophytes each from a natural population of Norway spruce. A RAPD linkage map for a single individual from the same population had previously been constructed. Using 30 random decamers that had yielded 83 RAPD markers in the single-tree map, eight megagametophytes for each of the 48 sibships were screened. The linkage relationship among markers was estimated considering each family of eight megagametophytes as a progeny of a phase-unknown backcross mating between a heterozygous mother and a fictitious ‘recessive’ father. Markers were assigned to windows using LOD=2.0 and θ=0.4 as thresholds, and ordered using a criterion of interval support ≥2.0. For eight “windows” of recombination selected on the single-tree map, we investigated the consistency of marker order in the two maps. We adopted restrictive criteria for rejecting co-linearity between the two locus orders. For each window we imposed the most likely locus order obtained from one data set to the other (and vice versa), obtaining two symmetrical log-likelihood differences. We considered the hypothesis of co-linearity rejected when both symmetrical differences were significant (ΔLOD>3.0). By bootstrapping a subset of markers for each window (highly informative, ‘framework’ loci chosen on the previous single-tree map using a matrix correlation method) the sampling variability of the single-tree and population maps was estimated. As expected the population map was affected by a larger variability than the single-tree map. Heterogeneity in pairwise recombination fractions among groups of sibship revealed a (possible) alternative genomic arrangement detected within a single recombination window.Theoretical and Applied Genetics 08/1997; 95(4):643-654. · 3.30 Impact Factor -
Article: Egg diapause and clonal structure in parthenogenetic populations of Heterocypris incongruens (Ostracoda)
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ABSTRACT: A study of the clonal structure of parthenogenetic populations of Heterocypris incongruens from rice-fields in Northern Italy carried out over two-year period is summarized. Significantly different levels of genetic polymorphism were found among populations. The coexistence of different electrophoretic clones and similar patterns of clonal seasonal succession have been observed in at least two different rice fields. The clone or group of clones present in fall, winter and early spring is substituted by other multilocus genotypes in late spring and summer. Different egg diapause induction mechanisms drive the clonal substitution in different clones. Here we report a new laboratory experiment designed to test the effect of temperature and photoperiod found in winter (12 C 8:16 L:D), spring (24C 12:12 L:D) and summer (28C 16:8 L:D) conditions on the deposition and hatching of diapausal eggs in different multilocus genotypes. Clones respond in a way compatible with their sustained presence in the field in different seasons.Hydrobiologia 01/1996; 320(1):45-54. · 1.78 Impact Factor -
Article: Segregation analysis of random amplified polymorphic DNA (RAPD) markers in Picea abies Karst.
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ABSTRACT: The reliability of arbitrarily primed amplification products was tested. The segregation analysis of 266 amplification products obtained using 17 different 10-mer oligonucleotides in 34 megagametophytes from a single tree of Picea abies was carried out. Fifty-four out of the 165 variable bands fit the 1:1 segregation ratio expected for Mendelian traits. The segregation ratio of a subset of six RAPD markers in five other individuals from the same population confirmed their genetic nature. Our results strengthen the evidence previously reported that RAPDs markers can be considered Mendelian traits useful in the detection of genetic variability among both different individuals and populations.Molecular Ecology 09/1993; 2(4):227-32. · 5.52 Impact Factor -
Article: Bridging the gap between ecophysiological and genetic knowledge to assess the adaptive potential of European beech
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ABSTRACT: In this study we aimed to combine knowledge of the ecophysiology and genetics of European beech to assess the potential of this species to adapt to environmental change. Therefore, we performed field and experimental studies on the genetic and ecophysiological functioning of beech. This information was integrated through a coupled genetic–ecophysiological model for individual trees that was parameterized with information derived from our own studies or from the literature. Using the model, we evaluated the adaptive response of beech stands in two ways: firstly, through sensitivity analyses (of initial genetic diversity, pollen dispersal distance, heritability of selected phenotypic traits, and forest management, representing disturbances) and secondly, through the evaluation of the responses of phenotypic traits and their genetic diversity to four management regimes applied to 10 study plots distributed over Western Europe. The model results indicate that the interval between recruitment events strongly affects the rate of adaptive response, because selection is most severe during the early stages of forest development. Forest management regimes largely determine recruitment intervals and thereby the potential for adaptive responses. Forest management regimes also determine the number of mother trees that contribute to the next generation and thereby the genetic variation that is maintained. Consequently, undisturbed forests maintain the largest amount of genetic variation, as recruitment intervals approach the longevity of trees and many mother trees contribute to the next generation. However, undisturbed forests have the slowest adaptive response, for the same reasons.Gene flow through pollen dispersal may compensate for the loss in genetic diversity brought about by selection. The sensitivity analysis showed that the total genetic diversity of a 2 ha stand is not affected by gene flow if the pollen distance distribution is varied from highly left-skewed to almost flat. However, a stand with a prevailing short-distance gene flow has a more pronounced spatial genetic structure than stands with equal short- and long-distance gene flows. The build-up of a spatial genetic structure is also strongly determined by the recruitment interval. Overall, the modelling results indicate that European beech has high adaptive potential to environmental change if recruitment intervals are short and many mother trees contribute to the next generation.The findings have two implications for modelling studies on the impacts of climate change on forests. Firstly: it cannot be taken for granted that parameter values remain constant over a time horizon of even a few generations – this is particularly important for threshold values subject to strong selection, like budburst, frost hardiness, drought tolerance, as used in species area models. Secondly: forest management should be taken into account in future assessments, as management affects the rate of adaptive response and thereby the response on trees and forests to environmental change, and because few forests are unmanaged. We conclude that a coupled ecophysiological and quantitative genetic tree model is a useful tool for such studies.Ecological Modelling.
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- Theoretical and Applied Genetics (2)
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Institutions
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1993–2012
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Università degli studi di Parma
Parma, Emilia-Romagna, Italy
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