03004nas a2200277   4500008004100000020001400041245012700055210006900182300001200251520209300263653003102356653003702387653002202424653001802446653001802464653001102482653002702493653002702520653002402547653002402571100002102595700002102616700002202637700002302659856004402682       2014                        eng d  a1365-269900aInfluence of climatic niche suitability and geographical overlap on hybridization patterns among southern Californian oaks0 aInfluence of climatic niche suitability and geographical overlap  an/a-n/a3 aAim Information on the association between geographical patterns of hybridization and the climatic niche requirements and co-occurrence of the species involved can provide important insights that further our understanding of the factors promoting the formation of hybrid zones. Here, we test whether climatic niche suitability explains patterns of hybridization beyond spatial overlap in distributions of the geographically restricted Engelmann oak (Quercus engelmannii) and the widespread scrub oak species complex (Quercus spp.). Location Southern California, USA. Methods We sampled Engelmann and scrub oaks across 31 localities and genotyped 343 individuals at nine microsatellite loci. We used climatic niche modelling to assess the suitability of habitats for each parental species and hybrids and to analyse whether climatic niche suitability in addition to co-occurrence are associated with observed spatial patterns of hybridization. Results Our data indicated that hybrid zones are located in areas that are geographically constrained by the presence of scattered patches of Engelmann oak within a matrix broadly occupied by scrub oaks. However, the climatic niche of hybrids differed from that occupied by both Engelmann and scrub oaks, suggesting the importance of climate on their establishment and persistence beyond the simple role of geographical overlap of parental species distributions. We also found that even moderate levels of introgression contributed to increased genetic diversity in Engelmann oak but not in scrub oaks. Main conclusions These results show that hybrid zones follow a mosaic pattern constrained by the presence of scattered patches occupied by Engelmann oak and climatically suitable areas that favour the establishment of hybrids. The low rates of ongoing hybridization and the bimodal distribution of parental genotypes found here suggest that hybridization is not threatening Engelmann oak and this phenomenon could instead be promoting the acquisition of favourable alleles that may increase the adaptive potential of this vulnerable species.10aEcological niche modelling10aextinction through hybridization10agenetic diversity10aHYBRIDIZATION10aintrogression10aMaxent10amicrosatellite markers10aperipheral populations10aQuercus engelmannii10asouthern California1 aOrtego, Joaquín1 aGugger, Paul, F.1 aRiordan, Erin, C.1 aSork, Victoria, L.  uhttps://quercus.myspecies.info/node/16602636nas a2200217   4500008004100000020001400041245010500055210006900160260002900229300001000258520193300268653001802201653001802219653001602237653003302253100002402286700002502310700001702335700002202352856004402374       2012                        eng d  a1365-294X00aMitochondrial barcodes are diagnostic of shared refugia but not species in hybridizing oak gallwasps0 aMitochondrial barcodes are diagnostic of shared refugia but not   bBlackwell Publishing Ltd  ano-no3 aMitochondrial DNA barcodes provide a simple taxonomic tool for systematic and ecological research, with particular benefit for poorly studied or species-rich taxa. Barcoding assumes genetic diversity follows species boundaries; however, many processes disrupt species-level monophyly of barcodes leading to incorrect classifications. Spatial population structure, particularly when shared across closely related and potentially hybridizing taxa, can invalidate barcoding approaches yet few data exist to examine its impacts. We test how shared population structure across hybridizing species impacts upon mitochondrial barcodes by sequencing the cytochrome b gene for 518 individuals of four well-delimited Western Palaearctic gallwasp species within the Andricus quercuscalicis species group. Mitochondrial barcodes clustered individuals into mixed-species clades corresponding to refugia, with no difference in within- and between-species divergence. Four nuclear genes were also sequenced from 4 to 11 individuals per refugial population of each species. Multi-locus analyses of these data supported established species, with no support for the refugial clustering across species seen in mitochondrial barcodes. This pattern is consistent with mitochondrial introgression among populations of species sharing the same glacial refugium, such that mitochondrial barcodes identify a shared history of population structure rather than species. Many taxa show phylogeographic structure across glacial refugia, suggesting that mitochondrial barcoding may fail when applied to other sets of co-distributed, closely related species. Robust barcoding approaches must sample extensively across population structure to disentangle spatial from species-level variation. Methods incorporating multiple unlinked loci are also essential to accommodate coalescent variation among genes and provide power to resolve recently diverged species.10aDNA barcoding10aintrogression10amulti-locus10aspatial population structure1 aNicholls, James, A.1 aChallis, Richard, J.1 aMutun, Serap1 aStone, Graham, N.  uhttps://quercus.myspecies.info/node/14902535nas a2200229   4500008004100000245017900041210006900220260000900289300001200298490000700310520178800317653002002105653002002125653001802145653001802163653001902181100001502200700001602215700001602231700001502247856004302262       2007                        eng d00aPhylogeographic structure and late Quaternary population history of the Japanese oak Quercus mongolica var. crispula and related species revealed by chloroplast DNA variation0 aPhylogeographic structure and late Quaternary population history  c2007  a465-4770 v823 aGenerally, oaks dominate the broadleaf deciduous forests in Japan. The genetic variation in 6 cpDNA regions (trnT-trnL, trnL-trnF, atpB-rbcL, and trnH-psbA speacers, trnL intron, and matK gene) with regard to the Japanese oak (Quercus mongolica var. crispula) and 3 related species in the section Prinus (Q. serrata, Q. dentata and Q. aliena) was investigated in 598 trees belonging to 44 populations distributed throughout the Japanese archipelago. Additional samples were collected from Korea, China, and Russia (Sakhalin). Thirteen haplotypes (I to XIII) were identified on the bases of 15 nucleotide substitutions and 3 indels. Haplotypes I and II were discovered in northeastern Japan, whereas haplotypes III to IX were distributed in southwestern Japan. The boundary distinguishing these 2 groups was located in central Japan coincident with the Itoigawa-Shzuoka tectonic line. Haplotype I was also found in Sakhalin, whereas haplotypes VI, VII, VIII, X, XI, XII, and XIII were found in Korea and China. Four oak species in the same location shared identical haplotypes, suggesting cpDNA introgression by occasional hybridization. Both the values of total haplotype diversity (HT) and haplotype diversity within populations (HS) in Q. mongolica var. crispula were higher in the southwestern populations than in the northeastern populations. A haplotype network indicated that haplotype VI is the ancestral haplotype. The presence of identical haplotypes in Korea, China, and Japan suggested that the haplotypes diversified on the Eurasian continent before the last glacial period. The difference in genetic structure between the northeastern and southwestern regions indicates a difference in the history of migration and recolonization in Japan during the last glacial period.10acpDNA haplotype10aglacial periods10aintrogression10aJapanese oaks10aphylogeography1 aOkaura, T.1 aQuang, N.D.1 aUbukata, M.1 aHarada, K.  uhttps://quercus.myspecies.info/node/2402289nas a2200265   4500008004100000245013400041210006900175300001200244490000700256520147500263653001401738653002801752653001701780653001801797653002001815653001201835100002601847700003001873700001501903700001601918700001301934700002101947700001201968856004301980       2005                        eng d00aGene flow and hybridisation in a mixed oak forest (Quercus pyrenaica Willd. and Quercus petraea (Matts.) Liebl.) in central Spain0 aGene flow and hybridisation in a mixed oak forest Quercus pyrena  a457-4650 v953 aOaks are long-standing models for the study of gene flow and hybridisation. Temperate (Quercus petraea) and sub-Mediterranean (Quercus pyrenaica) oaks coexist in central Spain, showing remarkable differences in population size and structure. Q. petraea has a scattered distribution in central Spain, where it is at one of the southernmost limits of its range, and forms low-density stands; in contrast, Q. pyrenaica is widespread in the region. We selected a mixed population of the two species (approx13 ha, 176 adults and 96 saplings) to compare the patterns of gene flow within each species and the extent of introgression between them. Using five nuclear microsatellite markers, we performed a parentage analysis and found considerable immigration from outside the stand (approx38% for Q. petraea and approx34% for Q. pyrenaica), and estimated average seed-dispersal distances of 42 and 14 m for Q. petraea and Q. pyrenaica, respectively. Introgression between species was also estimated using our microsatellite battery. First, we developed a multivariate discriminant approach and, second, we compared our results with a widely used clustering method (STRUCTURE). Both analyses were consistent with a low level of introgression between Q. petraea and Q. pyrenaica. Indeed, only 15 adult trees, approx8.5%, were identified as putative hybrids when both methods of analysis were combined. Hybrids may be most common in contact zones due merely to physical proximity.10agene flow10agenetic differentiation10ahybrid zones10aintrogression10amicrosatellites10aQuercus1 aValbuena-Carabana, M.1 aGonzalez-Martinez, S., C.1 aSork, V.L.1 aCollada, C.1 aSOTO, A.1 aGoicoechea, P.G.1 aGil, L.  uhttps://quercus.myspecies.info/node/3602506nas 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/39