02042nas a2200217   4500008004100000245014300041210006900184260000900253300001400262490000800276520134000284100002501624700001701649700001401666700002101680700001901701700001601720700001301736700001501749856006001764       2004                        eng d00aGenome Scanning for Interspecific Differentiation Between Two Closely Related Oak Species [Quercus robur L. and Q. petraea (Matt.) Liebl.]0 aGenome Scanning for Interspecific Differentiation Between Two Cl  c2004  a1615-16260 v1683 aInterspecific differentiation values (GST) between two closely related oak species (Quercus petraea and Q. robur) were compiled across different studies with the aim to explore the distribution of differentiation at the genome level. The study was based on a total set of 389 markers (isozymes, AFLPs, SCARs, microsatellites, and SNPs) for which allelic frequencies were estimated in pairs of populations sampled throughout the sympatric distribution of the two species. The overall distribution of GST values followed an L-shaped curve with most markers exhibiting low species differentiation (GST < 0.01) and only a few loci reaching >10% levels. Twelve percent of the loci exhibited significant GST deviations to neutral expectations, suggesting that selection contributed to species divergence. Coding regions expressed higher differentiation than noncoding regions. Among the 389 markers, 158 could be mapped on the 12 linkage groups of the existing Q. robur genetic map. Outlier loci with large GST values were distributed over 9 linkage groups. One cluster of three outlier loci was found within 0.51 cM; but significant autocorrelation of GST was observed at distances <2 cM. The size and distribution of genomic regions involved in species divergence are discussed in reference to hitchhiking effects and disruptive selection.1 aScotti-Saintagne, C.1 aMariette, S.1 aPorth, I.1 aGoicoechea, P.G.1 aBarreneche, T.1 aBodenes, C.1 aBurg, K.1 aKremer, A.  uhttp://www.genetics.org/cgi/content/abstract/168/3/161501996nas a2200169   4500008004100000245012500041210006900166260000900235300001200244490000700256520145500263100000501718700001601723700001701739700001401756856005601770       2004                        eng d00aMorphological and RAPD analysis of hybridization between Quercus affinis and Q. laurina (fagaceae), two Mexican red oaks0 aMorphological and RAPD analysis of hybridization between Quercus  c2004  a401-4090 v913 aQuercus affinis and Q. laurina are two closely related Mexican red oaks with partially overlapping distributions. Within the area of overlap, there are localities where morphological intergradation occurs. A previous hypothesis explained this pattern as a result of secondary contact between the two species, followed by hybridization and introgression. This possibility was analyzed here by examining foliar and genetic variation in 16 localities situated along a macrogeographic gradient, which included morphologically representative populations of both species and populations from within the area of overlap. Maximum-likelihood hybrid index scores calculated from nine semi-diagnostic RAPD markers indicated a shift in the genetic composition of populations from one species to the other along the macrogeographic gradient, with genetically intermediate populations situated in the area of overlap. Foliar variation followed a partially congruent pattern, but Q. laurina-like morphology predominated in some of the genetically intermediate populations. There were several instances of correlated frequency changeovers of single RAPD markers and morphological characters along the macrogeographic gradient and a few cases of markedly parallel patterns between markers. The results were interpreted as consistent with a hypothesis of secondary contact between the two oak species that has resulted in some differential introgression among markers.1 a1 aArias, D.M.1 aValencia, S.1 aOyama, K.  uhttp://www.amjbot.org/cgi/content/abstract/91/3/40102506nas a2200217   4500008004100000245006100041210006100102260000900163300001200172490000700184520191500191653001202106653001802118653001802136653002102154653002202175653001302197100001502210700002002225856004302245       2004                        eng d00aSelection and disperal in a multispecies oak hybrid zone0 aSelection and disperal in a multispecies oak hybrid zone  c2004  a261-2690 v583 aThe four western North American red oak species (Quercus wislizeni, Q. parvula, Q. agrifolia, and Q. kelloggii) are known to produce hybrid products in all interspecific combinations. However, it is unknown whether hybrids are transitory resulting from interspecific gene flow or whether they are maintained through extrinsic selection. Here, we examine cryptic hybrid structure in Q. wislizeni through a broad region including contact and isolation from three other western North American red oaks using amplified fragment length polymorphism molecular markers. All four species were simultaneously detected in the genetic background of individuals morphologically assigned to Q. wislizeni, although the contribution of Q. kelloggii was minor. In some cases, introgression was detected well outside the region of sympatry with one of the parental species. Molecular structure at the individual level indicated this was due to long-distance pollen dispersal and not to local extinction of parental species. Species admixture proportions were correlated with climatic variables and greater proportions of Q. agrifolia and Q. parvula were present in the genetic background of Q. wislizeni in sites with cooler and more humid summers, corresponding with habitat preferences of the parental species. Partial Mantel tests indicated that climate was more important than distance from pollen source in this association. Despite high levels of introgression, species integrity was maintained in some populations in close proximity to the other species, providing further support to environmental selection in determining population genetic structure. Thus, the contribution of species mixtures to population genetic structure varies across the landscape according to availability of pollen, but more importantly to varying environmental selection pressures that produce a complex pattern of hybrid and pure gene pools.10aClimate10aHYBRIDIZATION10aintrogression10apollen dispersal10aQuercus wislizeni10ared oaks1 aDodd, R.S.1 aAfzal-Rafii, Z.  uhttps://quercus.myspecies.info/node/3902566nas a2200373   4500008004100000245014100041210006900182260000900251300001200260490000700272520139600279653002301675653005401698653001801752653001201770653001901782653002801801653001401829653001401843653004801857653001301905653001201918653003301930653003901963653001802002653001902020653002002039653002002059100001602079700002002095700001602115700001802131856004302149       2004                        eng d00aTwo-generation analysis of pollen flow across a landscape V: A stepwise approach for extracting factors contributing to pollen structure0 aTwogeneration analysis of pollen flow across a landscape V A ste  c2004  a204-2110 v923 aPatterns of pollen dispersal are central to both the ecology and evolution of plant populations. However, the mechanisms controlling either the dispersal process itself or our estimation of that process may be influenced by site -specific factors such as local forest structure and nonuniform adult genetic structure. Here, we present an extension of the AMOVA model applied to the recently developed TWOGENER analysis of pollen pool structure. This model, dubbed the Stepwise AMOVA (StAMOVA), focuses on determining to what extent ecological, demographic, and/or environmental factors influence the observed genetic variation in spatially separated pollen pools. The analysis is verified for efficacy, using an extensive battery of simulations, illustrating: (1) how nonuniform adult genetic structure influences the differentiation of spatially separated pollen pools, and (2) how effectively the Stepwise analysis performs in carrying out the appropriate corrections. Finally, the model is applied to a Quercus alba data set, from which we have prior evidence that the adult genetic structure is nonuniformly distributed across the sampling landscape. From this data set, we show how the Stepwise model can be applied to remove the effects of spatial adult genetic structure on pollen pool differentiation and contrast these results with those derived from the original TWOGENER analysis.10a[26070-] Fagaceae-10aAMOVA-model: mathematical-and-computer-techniques10aAngiospermae-10aDicots-10aDicotyledones-10aFagaceae-: Angiosperms-10agene-flow10aGenetics-10aMathematical-Biology: Computational-Biology10aPlantae-10aPlants-10apollen-: reproductive-system10aQuercus-alba (Fagaceae-): species-10aReproduction-10aSpermatophyta-10aSpermatophytes-10aVascular-Plants1 aDyer, R.-J.1 aWestfall, R.-D.1 aSork, V.-L.1 aSmouse, P.-E.  uhttps://quercus.myspecies.info/node/40