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4,287 results for “Asteraceae”
Data from: Conflicting phylogenomic signals reveal a pattern of reticulate evolution in a recent high-Andean diversification (Asteraceae: Astereae: Diplostephium)
High-throughput sequencing is helping biologists to overcome the difficulties of inferring the phylogenies of recently diverged taxa. The present study analyzes the phylogenetic signal of genomic regions with different inheritance patterns using genome skimming and ddRAD-seq in a species-rich Andean genus (Diplostephium) and its allies. We analyzed the complete nuclear ribosomal cistron, the complete chloroplast genome, a partial mitochondrial genome, and a nuclear-ddRAD matrix separately with phylogenetic methods. We applied several approaches to understand the causes of incongruence among datasets, including simulations and the detection of introgression using the D-statistic (ABBA-BABA test). We found significant incongruence among the nuclear, chloroplast, and mitochondrial phylogenies. The strong signal of hybridization found by simulations and the D-statistic among genera and inside the main clades of Diplostephium indicate reticulate evolution as a main cause of phylogenetic incongruence. Our results add evidence for a major role of reticulate evolution in events of rapid diversification. Hybridization and introgression confound chloroplast and mitochondrial phylogenies in relation to the species tree as a result of the uniparental inheritance of these genomic regions. Practical implications regarding the prevalence of hybridization are discussed in relation to the phylogenetic method.
Data from: Macroevolutionary dynamics in the early diversification of Asteraceae
Spatial and temporal differences in ecological opportunity can result in disparity of net species diversification rates and consequently uneven distribution of taxon richness across the tree of life. The largest eudicotyledonous plant family Asteraceae has a global distribution and at least 460 times more species than its South American endemic sister family Calyceraceae. In this study, diversification rate dynamics across Asteraceae are examined in light of the several hypothesized causes for the family's evolutionary success that could be responsible for rate change. The innovations of racemose capitulum and pappus, and a whole genome duplication event occurred near the origin of the family, yet we found the basal lineages of Asteraceae that evolved in South America share background diversification rates with Calyceraceae and their Australasian sister Goodeniaceae. Instead we found diversification rates increased gradually from the origin of Asteraceae approximately 69.5 Ma in the late Cretaceous through the Early Eocene Climatic Optimum at least. In contrast to earlier studies, significant rate shifts were not strongly correlated with intercontinental dispersals or polyploidization. The difference is due primarily to sampling more backbone nodes, as well as calibrations placed internally in Asteraceae that resulted in earlier divergence times than those found in most previous relaxed clock studies. Two clades identified as having transformed rate processes are the Vernonioid Clade and a clade within the Heliantheae alliance characterized by phytomelanic fruit (PF Clade) that represents an American radiation. In Africa, subfamilies Carduoideae, Pertyoideae, Gymnarrhenoideae, Cichorioideae, Corymbioideae, and Asteroideae diverged in a relatively short span of only 6.5 million years during the Middle Eocene.
Data from: Artemisia baxoiensis (Asteraceae: Anthemideae), a distinctive new species from Xizang, China
A new species of Artemisia (Asteraceae: Antemideae) from Xizang, China, A. baxoiensis, is described, illustrated and discussed based on morphological, micromorphological and molecular phylogenetic evidence. It grows in Nu Jiang dry-hot valley and is narrowly distributed. This plant is similar to Neopallasia pectinata, but different in capitula and indumentum. Artemisia baxoiensis has distinctive morphology with pectinately pinnatisect leaf blade and unusually dense glandular hairs.
Data from: Breeding relationships in Macaronesian Tolpis (Asteraceae-Cichorieae): F1 hybrid pollen fertility within and among populations from the Azores, Canary Islands and Madeira
The pollen fertility of F1 hybrids, ranging from progeny within natural populations to synthetic hybrids between species of Tolpis from three archipelagos in Macaronesia, was determined. Pollen fertility of F1 hybrids of inter-archipelago crosses from the Azores, Canaries, and Madeira were generally lower than crosses between populations or species in the same archipelagos. Lower pollen fertility was pronounced in hybrids between plants from the Canaries and the other archipelagos, which is concordant with a more distant phylogenetic relationship between the Canaries, and the Azores and Madeira. Lower average pollen fertility was seen between plants from different as compared to the same clades in the Canary Islands. However, low pollen fertilities were also detected between plants from some populations/species in the same archipelagos, and even among progeny of individual maternal plants. Some hybrids with reduced fertility had meiotic irregularities, suggesting chromosomal rearrangements; in other cases meiosis appeared normal. Results indicate that postzygotic isolating factors evolved subsequent to the divergence of Tolpis in the three archipelagos, but there are hybrid sterility factors among plants within each of the archipelagos, and even within some natural populations. Phylogenetic relationships in the Canary Islands indicate that divergence has occurred within the last million years. Present results implicate postzygotic factors as reproductive barriers facilitating population divergence and speciation in Macaronesian Tolpis.
Data from: The impact of reconstruction methods, phylogenetic uncertainty and branch lengths on inference of chromosome number evolution in American daisies (Melampodium, Asteraceae)
Chromosome number change (polyploidy and dysploidy) plays an important role in plant diversification and speciation. Investigating chromosome number evolution commonly entails ancestral state reconstruction performed within a phylogenetic framework, which is, however, prone to uncertainty, whose effects on evolutionary inferences are insufficiently understood. Using the chromosomally diverse plant genus Melampodium (Asteraceae) as model group, we assess the impact of reconstruction method (maximum parsimony, maximum likelihood, Bayesian methods), branch length model (phylograms versus chronograms) and phylogenetic uncertainty (topological and branch length uncertainty) on the inference of chromosome number evolution. We also address the suitability of the maximum clade credibility (MCC) tree as single representative topology for chromosome number reconstruction. Each of the listed factors causes considerable incongruence among chromosome number reconstructions. Discrepancies between inferences on the MCC tree from those made by integrating over a set of trees are moderate for ancestral chromosome numbers, but severe for the difference of chromosome gains and losses, a measure of the directionality of dysploidy. Therefore, reliance on single trees, such as the MCC tree, is strongly discouraged and model averaging, taking both phylogenetic and model uncertainty into account, is recommended. For studying chromosome number evolution, dedicated models implemented in the program ChromEvol and ordered maximum parsimony may be most appropriate. Chromosome number evolution in Melampodium follows a pattern of bidirectional dysploidy (starting from x = 11 to x = 9 and x = 14, respectively) with no prevailing direction.
Data from: Genetic and ecotypic differentiation in a Californian plant polyploid complex (Grindelia, Asteraceae)
Studies of ecotypic differentiation in the California Floristic Province have contributed greatly to plant evolutionary biology since the pioneering work of Clausen, Keck, and Hiesey. The extent of gene flow and genetic differentiation across interfertile ecotypes that span major habitats in the California Floristic Province is understudied, however, and is important for understanding the prospects for local adaptation to evolve or persist in the face of potential gene flow across populations in different ecological settings. We used microsatellite data to examine local differentiation in one of these lineages, the Pacific Coast polyploid complex of the plant genus Grindelia (Asteraceae). We examined 439 individuals in 10 different populations. The plants grouped broadly into a coastal and an inland set of populations. The coastal group contained plants from salt marshes and coastal bluffs, as well as a population growing in a serpentine grassland close to the coast, while the inland group contained grassland plants. No evidence for hybridization was found at the single location where adjacent populations of the two groups were sampled. In addition to differentiation along ecotypic lines, there was also a strong signal of local differentiation, with the plants grouping strongly by population. The strength of local differentiation is consistent with the extensive morphological variation observed across populations and the history of taxonomic confusion in the group. The Pacific Clade of Grindelia and other young Californian plant groups warrant additional analysis of evolutionary divergence along the steep coast-to-inland climatic gradient, which has been associated with local adaptation and ecotype formation since the classic studies of Clausen, Keck, and Hiesey.
Data from: Taxonomic revision of Dasyphyllum sect. Macrocephala (Asteraceae: Barnadesioideae)
Dasyphyllum sect. Macrocephala is restricted to the Cerrado, Caatinga, and Atlantic Forest biomes of Brazil, spreading into similar areas in Bolivia and Paraguay. The six recognized species in this section are monoecious shrubs with erect or decumbent branches, single or paired, rarely fasciculate, straight or curved axillary spines, leaves with apiculate or aristate apices, 5–7 basally or suprabasally acrodromous veins, sessile capitula, usually solitary or in groups of two to four, a campanulate or infundibuliform involucre generally longer than 20 mm, and with hermaphroditic florets usually with liguliform corollas and externally sericeous lobes. An identification key, descriptions, comments regarding morphology and taxonomy, maps showing geographical distribution, and illustrations are presented, together with 17 new synonyms and 18 typifications.
Data from: Genome-wide SNP discovery in the annual herb, Lasthenia fremontii (Asteraceae): genetic resources for the conservation and restoration of a California vernal pool endemic
California vernal pool (VP) ecosystems support a diverse community of endemic plants that are threatened by multiple anthropogenic pressures, generating a need for molecular tools to quantify the extent and distribution of genetic variation in native populations. Here, we used RADseq to discover single nucleotide polymorphisms (SNPs) for a widespread VP endemic plant species, Lasthenia fremontii. We discovered nuclear-based SNPs using a RAD-tag library of 12 individuals from different VP complexes using SbfI, a restriction enzyme that does not cleave the chloroplast genome in Lasthenia. A total of 316,106 catalog loci were obtained across all twelve individuals in the library. Of these, 713 loci were polymorphic, yielding 3918 candidate SNPs. Next, we genotyped an additional 285 additional plants to validate and characterize 71 of the candidate SNPs. Of these, 44 were polymorphic among VP complexes. A preliminary analysis of the distribution of genetic variation using these loci revealed significant isolation-by-distance across the species' geographic range. Weaker, but in some cases significant, genetic differentiation was detected among subpopulations from different pools within a single VP complex. Thus, in this study, RADseq allowed the discovery of SNP markers that can characterize patterns of genetic variation at multiple spatial scales in L. fremontii, which can be used to inform the conservation and mitigation of VP populations.
Data from: Molecular phylogeny of Tragopogon L. (Asteraceae) based on seven nuclear loci (Adh, GapC, LFY, AP3, PI, ITS, and ETS)
Tragopogon is a large Eurasian genus of approximately 150 species. Despite the use of 6910 aligned bp of sequence data representing seven loci, relationships within the genus remain largely unresolved. The young age of the genus in combination with rapid diversification may be the best explanation for this poor resolution. Our studies have revealed that Geropogon is well supported as the immediate sister to Tragopogon. Sections Tragopogon, Brevirostris, Chromopappus, and Hebecarpus of traditional taxonomic treatments are largely monophyletic; sections Angustissimi, Majores, Collini, and Profundisulcati are non-monophyletic. The monotypic sections Macropogon, Dasypogon, and Dybjanskya appear within other sections and no longer merit recognition. Our molecular investigations of geographically widespread species in Europe, including T. crocifolius, T. pratensis, T. porrifolius, and T. orientalis, indicate that each may be non-monophyletic, comprising several cryptic species. These widespread diploids are the proposed parents of some of the Eurasian allopolyploids, as well as the parents of the recently formed T. mirus and T. miscellus from North America
Data from: Ecological differentiation, lack of hybrids involving diploids, and asymmetric gene flow between polyploids in narrow contact zones of Senecio carniolicus (syn. Jacobaea carniolica, Asteraceae)
Areas of immediate contact of different cytotypes offer a unique opportunity to study evolutionary dynamics within heteroploid species and to assess isolation mechanisms governing coexistence of cytotypes of different ploidy. The degree of reproductive isolation of cytotypes, i.e., the frequency of heteroploid crosses and subsequent formation of viable and (partly) fertile hybrids, plays a crucial role for the long-term integrity of lineages in contact zones. Here, we assessed fine-scale distribution, spatial clustering and ecological niches as well as patterns of gene-flow in parental and hybrid cytotypes in zones of immediate contact of di-, tetra- and hexaploid Senecio carniolicus (Asteraceae) in the Eastern Alps. Cytotypes were spatially separated also at the investigated micro-scale; the strongest spatial separation was observed for the fully interfertile tetra- and hexaploids. The three main cytotypes showed highly significant niche differences, which were, however, weaker than across their entire distribution ranges in the Eastern Alps. Individuals with intermediate ploidy levels were found neither in the diploid/tetraploid nor in the diploid/hexaploid contact zones indicating strong reproductive barriers. In contrast, pentaploid individuals were frequent in the tetraploid/hexaploid contact zone, albeit limited to a narrow strip in the immediate contact zone of their parental cytotypes. AFLP fingerprinting data revealed introgressive gene flow mediated by pentaploid hybrids from tetra- to hexaploid individuals, but not vice versa. The ecological niche of pentaploids differed significantly from that of tetraploids but not from hexaploids.
Data from: The influence of contemporary and historic landscape features on the genetic structure of the sand dune endemic, Cirsium pitcheri (Asteraceae)
Narrow endemics are at risk from climate change due to their restricted habitat preferences, lower colonization ability and dispersal distances. Landscape genetics combines new tools and analyses that allow us to test how both past and present landscape features have facilitated or hindered previous range expansion and local migration patterns, and thereby identifying potential limitations to future range shifts. We have compared current and historic habitat corridors in Cirsium pitcheri, an endemic of the linear dune ecosystem of the Great Lakes, to determine the relative contributions of contemporary migration and post-glacial range expansion on genetic structure. We used seven microsatellite loci to characterize the genetic structure for 24 populations of Cirsium pitcheri, spanning the center to periphery of the range. We tested genetic distance against different measures of geographic distance and landscape permeability, based on contemporary and historic landscape features. We found moderate genetic structure (ave Fst =0.14), and a north -south pattern to the distribution of genetic diversity and inbreeding, with northern populations having the highest diversity and lowest levels of inbreeding. High allelic diversity, small average pairwise distances and mixed genetic clusters identified in Structure suggest populations in the center of the range represent the point of entry to the Lake Michigan and a refugia of diversity for this species. A strong association between genetic distances and lake level changes suggests that historic lake fluctuations best explain the broad geographic patterns, and sandy habitat best explain local patterns or movement.
Data from: Chryselium, a new South American genus segregated from Helichrysum (Asteraceae, Gnaphalieae)
Chryselium Urtubey & S. E. Freire, a new monotypic genus, is here described and illustrated to accomodate one species that was initially placed in Helichrysum, H. gnaphalioides, as Chryselium gnaphalioides . The new genus, Chryselium , is a monoecious herb with single stems and terminal capitulescences that are densely glomerulate from the Tropical Andes of Venezuela, Colombia, Ecuador, Bolivia, and Peru. This genus differs fundamentally from Helichrysum by having a stoloniferous habit and corollas with purple apices. A molecular analysis using DNA sequences from nuclear (ITS and ETS) markers placed this genus in a clade with Chevreulia, Cuatrecasasiella, Antennaria, and Diaperia in the FLAG group. Affinities of the new genus with genera previously assigned to Chryselium are also discussed.
Data from: Faberia pinnatifida (Asteraceae; Cichorieae), a new species from Sichuan, China
Faberia pinnatifida (Asteraceae; Cichorieae), a species occurring at high altitudes in Muli and Yanyuan Xian, Sichuan, China, is described as new based on morphological, palynological and molecular phylogenetic data. The ITS data indicate that F. pinnatifida is closely related to F. glaucescens and F. thibetica, but it is easily distinguished from F. glaucescens by its scapigerous stem with only one or two leaves, and from F. thibetica in its much taller stature and elliptic to oblanceolate leaf blade. Faberia pinnatifida somewhat resembles F. ceterach in the scapigerous stem and pinnatifid leaves, but readily differs in its corymbiform synflorescence and nodding capitula bearing ca. 30 florets.
Data from: Next-generation sampling: pairing genomics with herbarium specimens provides species-level signal in Solidago (Asteraceae)
Premise of the study: The ability to conduct species delimitation and phylogeny reconstruction with genomic data sets obtained exclusively from herbarium specimens would rapidly enhance our knowledge of large, taxonomically contentious plant genera. In this study, the utility of genotyping by sequencing is assessed in the notoriously difficult genus Solidago (Asteraceae) by attempting to obtain an informative single-nucleotide polymorphism data set from a set of specimens collected between 1970 and 2010. Methods: Reduced representation libraries were prepared and Illumina-sequenced from 95 Solidago herbarium specimen DNAs, and resulting reads were processed with the nonreference Universal Network-Enabled Analysis Kit (UNEAK) pipeline. Multidimensional clustering was used to assess the correspondence between genetic groups and morphologically defined species. Results: Library construction and sequencing were successful in 93 of 95 samples. The UNEAK pipeline identified 8470 single-nucleotide polymorphisms, and a filtered data set was analyzed for each of three Solidago subsections. Although results varied, clustering identified genomic groups that often corresponded to currently recognized species or groups of closely related species. Discussion: These results suggest that genotyping by sequencing is broadly applicable to DNAs obtained from herbarium specimens. The data obtained and their biological signal suggest that pairing genomics with large-scale herbarium sampling is a promising strategy in species-rich plant groups.
FIGURES 17–22 in New genera and host plant records of Asteraceaefeeding Tephritidae (Diptera) from Brazil
FIGURES 17–22. Lewinsohnia magna: 17, head, lateral; 18, aculeus, ventral; 19, aculeus tip, ventral; 20, glans, dorsal; 21, epandrium and surstyli, posterior; 22, epandrium, surstyli, hypandrium, phallapodeme and phallus, lateral, with glans, lateral.
FIGURES 11–14 in New genera and host plant records of Asteraceaefeeding Tephritidae (Diptera) from Brazil
FIGURES 11–14. Eutretopsis albipunctata, male and female terminalia: 11, aculeus, ventral; 12, aculeus tip, ventral; 13, glans, lateral; 14, glans, dorsal.
FIGURES 4–10 in New genera and host plant records of Asteraceaefeeding Tephritidae (Diptera) from Brazil
FIGURES 4–10. Cipomyia totofusca, male and female terminalia: 4, epandrium and surstyli, posterior; 5, base of phallus, phallapodeme, and hypandrium, ventral; 6, epandrium, surstyli, hypandrium, phallapodeme and base of phallus, lateral; 7, aculeus, ventral; 8, aculeus tip, ventral; 9, glans, lateral; 10, glans, dorsal.
FIGURES 1–8 in Asphondylia gochnatiae, a new species of gall midge (Diptera, Cecidomyiidae) associated with Gochnatia polymorpha (Less.) Cabrera (Asteraceae)
FIGURES 1–8. Asphondylia gochnatiae Maia, sp. nov. 1, male head (frontal). 2, male, flagellomeres 10–12. 3, female, flagellomere 10–12. 4, male, flagellomere 5. 5, female, flagellomere 5. 6, female, foreleg, tarsomere 1. 7, male, midleg, tarsal claw and empodium. 8, male, abdominal segments 5–8 (lateral).
FIGURES 9–14 in Asphondylia gochnatiae, a new species of gall midge (Diptera, Cecidomyiidae) associated with Gochnatia polymorpha (Less.) Cabrera (Asteraceae)
FIGURES 9–14. Asphondylia gochnatiae Maia, sp. nov. 9, male terminalia (dorsal). 10, female, abdominal segments 4– 8 (lateral). 11, pupal head (frontal). 12, pupa, prothoracic spiracle. 13, pupa, abdominal segments 8–9. 14, larva, prothoracic spatula, sternal and lateral papillae (ventral).
FIGURE 7 in A new species of Aceria (Acari: Eriophyidae) damaging sowthistles, Sonchus spp. (Asteraceae), in Australia with notes on Aceria sonchi (Nalepa, 1902)
FIGURE 7. Damage symptoms by Aceria thalgi sp. n. showing leaf rolling and curling of A Sonchus oleraceus, B S. asper and C S. hydrophilus. D Enlarged image of diseased leaf of S. oleraceus. Flowerhead damage on E S. oleraceus and F S. asper. Scale bar = 5 mm.
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Allen Brain Atlas
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DANDI Archive for NWB datasets
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International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.