Detection of genomic regions differentiating two closely related oak species Quercus petraea (Matt.) Liebl. and Quercus robur L.

Bodénès, Catherine; Joandet, S; Laigret, Frédéric; Kremer, Antoine

doi:10.1038/hdy.1997.67

Cited by 73 publications

(58 citation statements)

References 40 publications

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“…Ideally, many markers should be screened before an appropriate set of informative markers is se-lected. This pre-screening step is critical since the genetic differentiation between closely related oak species is generally very low at selectively neutral genetic markers as the result of past and ongoing interspecifi c gene fl ow and incomplete lineage sorting (Bodénès et al 1997, Muir & Schlötterer 2005. The availability of gene-based markers (EST-SSRs, Expressed Sequence Tag-Simple Sequence Repeats) for white (Durand et al 2010, Bodénès et al 2012) and red oaks (Fagaceae Genomics web, http://www.…”

Section: Genetic Admixture In Multispecies Oak Standsmentioning

confidence: 99%

Interspecific gene flow and maintenance of species integrity in oaks

Gailing

Curtu

2014

Ann. For. Res.

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Abstract. Oak species show a wide variation in morphological and physiological characters, and boundaries between closely related species are often not clear-cut. Still, despite frequent interspecific gene flow, oaks maintain distinct morphological and physiological adaptations. In sympatric stands, spatial distribution of species with different ecological requirements is not random but constrained by soil and other micro-environmental factors. Here, we discuss factors that may influence the maintenance of the integrity of oak species in the face of interspecific gene flow. Pre-zygotic isolation (e.g. cross incompatibilities, asynchrony in flowering, pollen competition) and post-zygotic isolation (divergent selection) contribute to the maintenance of species integrity in sympatric oak stands. The antagonistic effects of interspecific gene flow and divergent selection are reflected in the low genetic differentiation between hybridizing oak species at most genomic regions interspersed by regions with signatures of divergent selection (outlier regions). In the near future, the availability of high-density genetic linkage maps anchored to scaffolds of a sequenced Q. robur genome will allow to characterize the underlying genes in these outlier regions and their putative role in reproductive isolation between species. Reciprocal transplant experiments of seedlings between parental environments can be used to characterize selection on outlier genes. High transferability of gene-based markers will enable comparative outlier screens in different oak species.

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Section: Genetic Admixture In Multispecies Oak Standsmentioning

confidence: 99%

Interspecific gene flow and maintenance of species integrity in oaks

Gailing

Curtu

2014

Ann. For. Res.

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“…Sampling procedures or data analyses based on a priori grouping inevitably introduced circularity in the taxonomic assignment procedure. Alternative methods for species identification have been explored in recent years using either isozymes [4,32,35] or molecular techniques [7,23,24]. These methods generally assume that species separation was known and were used to compare frequencies of genetic markers between the two species.…”

Section: Introductionmentioning

confidence: 99%

Leaf morphological differentiation between Quercus robur and Quercus petraea is stable across western European mixed oak stands

Kremer¹,

et al. 2002

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-Leaf 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, an "easy to use" discriminant function applicable to a major part of the natural distribution of the species was constructed. Validation on an independent set of trees provided a 98% rate of correct identification. The results were interpreted in the light of earlier reports about extensive hybridization occurring in mixed oak stands. Maternal effects on morphological characters, as well as a lower frequency or fitness of hybrids in comparison with parent species could explain the maintenance of two modes, which might be composed of either pure species or pure species and introgressed forms. morphology / leaf / Quercus robur / Quercus petraea / taxonomyRésumé -La différenciation morphologique des feuilles entre Quercus robur et Quercus petraea est stable à travers les peuplements mé-langés de chênes de l'ouest européen. La variabilité de la morphologie foliaire a été etudiée dans neuf peuplements mélangés de chênes (Quercus petraea et Q. robur) en Europe sur la base d'un échantillon exhaustif moyen de 170 arbres/espèce/peuplement. Trois méthodes d'analyses multivariables ont été utilisées (ACD : analyse canonique discriminante ; ACP : analyse en composantes principales ; AFC : analyse factorielle des correspondances). Les trois méthodes aboutissent à des résultats congruents. La première variable synthétique de chaque méthode se Ann. For. Sci. 59 (2002)

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“…Consequently, many studies comparing Q. petraea and Q. robur use identification criteria based on leaf morphology. In particular, genetic studies aiming to find species-specific molecular markers still rely on morphological characters to define these two species [6,18,19].…”

Section: Introductionmentioning

confidence: 99%

Leaf morphology as species indicator in seedlings of Quercus robur L. and Q. petraea (Matt.) Liebl.: modulation by irradiance and growth flush

2004

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-Morphological description of leaves provides the most reliable criteria to discriminate between the two oak species Quercus petraea and Q. robur. However, most earlier studies only assessed leaf morphology of adult trees, whereas interspecific variations between seedlings were poorly documented. We studied variations of leaf morphology on two-year-old seedlings growing in a common garden experiment and exposed to different irradiance regimes. Morphological measurements were performed on leaves from each growth flush. Large interspecific differences were detected. The discrimination between the two species was slightly better with first flush leaves. Irradiance influenced leaf size, but did not affect the characters usually used to discriminate the two species, like relative petiole length or angle of auricle at the base of the lamina. A discriminant function, based on the two most discriminating traits (lamina pilosity density and angle of auricles at the lamina base), provided less than 0.5% leaf misclassification. It appeared that, contrary to what is generally accepted, species recognition of oak seedlings based on leaf morphology is possible. Moreover, this is true whatever the irradiance regime, and even slightly easier under light shade than in full sun. morphology / leaf / light / flush / oakRésumé -La morphologie foliaire comme indicateur spécifique chez les semis de Quercus robur L. et Q. petraea (Matt.) Liebl.: variation avec l'éclairement et l'unité de croissance. La discrimination taxonomique des espèces Quercus petraea et Q. robur est essentiellement basée sur l'examen des fructifications, souvent absentes, ou de la morphologie foliaire. Alors que l'ensemble des travaux sur le sujet concerne des arbres adultes, nous avons étudié les variations morphologiques foliaires de jeunes plants de Q. petraea et Q. robur croissant sous différents régimes d'éclairement. La morphologie des feuilles des différents flushs a été analysée durant la deuxième année de croissance des plants en pépinière. Une analyse factorielle des correspondances portant sur l'ensemble de l'échantillon et intégrant toutes les variables morphologiques aboutit à une discrimination interspécifique nette dans la majorité des cas. La discrimination apparaît cependant meilleure pour les feuilles de la première unité de croissance. Le régime d'éclairement a principalement affecté la taille des feuilles. Les variables usuelles permettant la discrimination morphologique entre Q. petraea et Q. robur n'ont pas été affectées par les différences d'éclairement. Une fonction discriminante a été construite avec les deux variables les plus discriminantes (densité de pilosité du limbe et angle des oreillettes), aboutissant à moins de 0.5 % d'erreur dans le classement des feuilles. Contrairement à une opinion répandue, la discrimination des espèces de chêne est possible dès le stade jeune plant. De plus, elle ne nécessite pas obligatoirement l'observation des seules feuilles développées en pleine lumière. Elle est même légèrement meilleure sou...

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Detection of genomic regions differentiating two closely related oak species Quercus petraea (Matt.) Liebl. and Quercus robur L.

Cited by 73 publications

References 40 publications

Interspecific gene flow and maintenance of species integrity in oaks

Interspecific gene flow and maintenance of species integrity in oaks

Leaf morphological differentiation between Quercus robur and Quercus petraea is stable across western European mixed oak stands

Leaf morphology as species indicator in seedlings of Quercus robur L. and Q. petraea (Matt.) Liebl.: modulation by irradiance and growth flush

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