01945nas a2200133   4500008004100000245005700041210005700098260000900155300001400164490000700178520156700185100001601752856004301768       1993                        eng d00aGene diversity in natural populations of oak species0 aGene diversity in natural populations of oak species  c1993  a186s-202s0 v503 aThis contribution reviews studies of nuclear and organelle gene diversity in oak species. Studies of allozymes were reported for 33 species belonging to the sections Erythrobalanus, Lepidobalanus and Mesobalanus of the genus Quercus. The extent and organization of gene diversity were investigated at 3 hierarchical levels: complex, species and population. Total diversity at the species and population level varies greatly among species (from 0.06 to 0.40). The range of variation among species is as large as that observed in other plant genera. Life history characteristics and evolutionary history are the main explanations for these results. Species with large and continuous distributions such as Q petraea and Q rubra exhibit high levels of gene diversity. Within a complex, most of the nuclear gene diversity is distributed within populations (74%). The remaining diversity is mainly due to species differentiation (23%), while the between-population component is low (3%). Organelle gene diversity has been investigated recently in 2 species complexes in the section Lepidobalanus (one in North America and one in Europe). Compared to nuclear genes, organelle gene diversity is strikingly different. Contributions of within-stand variation, species differentiation and population differentiation to total diversity, are respectively 13%, 11 % and 76%. Trees of a given population generally share the same chloroplast genome. Moreover, trees of different species (with reported introgression) occupying the same stand exhibit a high degree of similarity.1 aPetit, R.J.  uhttps://quercus.myspecies.info/node/8101007nas a2200145   4500008004100000245013100041210006900172260000900241300001200250490000700262520051600269100001500785700001800800856004300818       1999                        eng d00aAn efficient micro-method of DNA isolation from mature leaves of four hardwood tree species Acer, Fraxinus, Prunus and Quercus0 aefficient micromethod of DNA isolation from mature leaves of fou  c1999  a259-2630 v563 aIt is difficult to purify DNA from mature tree leaves at the end of the growing season, because of their thick cell wall, and high content in polysaccharides, phenolic compounds and endonucleases. A simple, fast and efficient method for DNA purification from 100 mg fresh weight leaf samples is described here. It has been developed for extracting DNA from mature leaves of Quercus, Fraxinus Prunus and Acer. The protocol is a modified CTAB (hexadecyltrimethylammonium bromide) method including a combination of1 aLefort, F.1 aDouglas, G.C.  uhttps://quercus.myspecies.info/node/6102355nas a2200337   4500008004100000245013200041210006900173260000900242300001200251490000700263520141100270100001501681700001601696700001401712700001701726700001501743700001801758700001601776700001501792700002001807700001601827700001701843700001601860700002201876700001301898700001601911700001401927700001801941700001501959856004301974       2002                        eng d00aLeaf morphological differentiation between Quercus robur and Quercus petraea is stable across western European mixed oak stands0 aLeaf morphological differentiation between Quercus robur and Que  c2002  a777-7870 v593 aLeaf morphology was assessed in nine mixed oak stands (Quercus petraea and Q. robur) located in eight European countries.Exhaustive sampling was used in an area of each stand where the two species coexisted in approximately equal proportions (about 170 trees/species/ stand). Fourteen leaf characters were assessed on each of 5 to10 leaves collected from the upper part of each tree. Three multivariate statistical techniques (CDA, canonical discriminant analysis; PCA, principal component analysis; MCA, multiple correspondence analysis) were used in two different ways: first on the total set of leaves over all stands (global analysis) and second, separately within each stand (local analysis). There was a general agreement of the results among the statistical methods used and between the analyses conducted (global and local). The first synthetic variable derived by each multivariate analysis exhibited a clear and sharp bimodal distribution, with overlapping in the central part. The two modes were interpreted as the two species, and the overlapping region was interpreted as an area where the within-species variations were superimposed. There was no discontinuity in the distribution or no visible evidence of a third mode which would have indicated the existence of a third population composed of trees with intermediate morphologies. Based on petiole length and number of intercalary veins, an1 aKremer, A.1 aDupouey, J.1 aDeans, J.1 aCottrell, J.1 aCsaikl, U.1 aFinkeldey, R.1 aEspinel, S.1 aJensen, J.1 aKleinschmit, J.1 aVan Dam, B.1 aDucousso, A.1 aForrest, I.1 ade Heredia, Lopez1 aLowe, A.1 aTutkova, M.1 aMunro, R.1 aSteinhoff, S.1 aBadeau, V.  uhttps://quercus.myspecies.info/node/52