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1.
The genus Caulerpa consists of about 75 species of tropical to subtropical siphonous green algae. To better understand the evolutionary history of the genus, a molecular phylogeny was inferred from chloroplast tufA sequences of 23 taxa. A sequence of Caulerpella ambigua was included as a potential outgroup. Results reveal that the latter taxon is, indeed, sister to all ingroup sequences. Caulerpa itself consists of a series of relatively ancient and species‐poor lineages and a relatively modern and rapidly diversifying clade, containing most of the diversity. The molecular phylogeny conflicts with the intrageneric sectional classification based on morphological characters and an evolutionary scheme based on chloroplast ultrastructure. High bootstrap values support monophyly of C. mexicana, C. sertularioides, C. taxifolia, C. webbiana, and C. prolifera, whereas most other Caulerpa species show para‐ or polyphyly.  相似文献   

2.
Baseline genotypes were established for 256 individuals of Caulerpa collected from 27 field locations in Florida (including the Keys), the Bahamas, US Virgin Islands, and Honduras, nearly doubling the number of available GenBank sequences. On the basis of sequences from the nuclear rDNA‐ITS 1+2 and the chloroplast tufA regions, the phylogeny of Caulerpa was reassessed and the presence of invasive strains was determined. Surveys in central Florida and southern California of >100 saltwater aquarium shops and 90 internet sites revealed that >50% sold Caulerpa. Of the 14 Caulerpa species encountered, Caulerpa racemosa was the most common, followed by Caulerpa sertularioides, Caulerpa prolifera, Caulerpa mexicana, and Caulerpa serrulata. None of the >180 field‐collected individuals (representing 13 species) was the invasive strain of Caulerpa taxifolia or C. racemosa. With one exception (a sample of C. racemosa from a shop in southern California belonged to the invasive Clade III strain), no invasive strains were found in saltwater aquarium stores in Florida or on any of the internet sites. Although these results are encouraging, we recommend a ban on the sale of all Caulerpa species (including “live rock”) because: morphological identification of Caulerpa species is unreliable (>12% misidentification rate) and invasive strains can only be identified by their aligned DNA sequences, and because the potential capacity for invasive behavior in other Caulerpa species is far from clear. The addition of the Florida region to the genetic data base for Caulerpa provides a valuable proactive resource for invasion biologists as well as researchers interested in the evolution and speciation of Caulerpa.  相似文献   

3.
The gastropod genus Cominella Gray, 1850 consists of approximately 20 species that inhabit a wide range of marine environments in New Zealand and Australia, including its external territory, the geographically isolated Norfolk Island. This distribution is puzzling, however, with apparently closely‐related species occurring either side of the Tasman Sea, even though all species are considered to have limited dispersal abilities. To determine how Cominella attained its current distribution, we derived a dated molecular phylogeny, which revealed a clade comprising all the Australian and Norfolk Island species nested within four clades of solely New Zealand species. This Australian clade diverged well after the vicariant separation of New Zealand from Australia, and implies two long‐distance dispersal events: a counter‐current movement across the Tasman Sea from New Zealand to Australia, occurring at the origination of the clade, followed by the colonization of Norfolk Island. The biology of Cominella suggests that the most likely method of long‐distance dispersal is rafting as egg capsules. Our robust phylogeny also means that the current Cominella classification requires revision. We propose that our clades be recognized as subgenera: Cominella (s.s.), Cominista, Josepha, Cominula, and Eucominia, with each subgenus comprising only of New Zealand or Australian species. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 115 , 315–332.  相似文献   

4.
Phylogenetic analysis of the genus Euscorpius (Scorpiones: Euscorpiidae) across the Mediterranean region (86 specimens, 77 localities, four DNA markers: 16S rDNA, COI, COII, and ITS1), focusing on Greek fauna, revealed high variation, deep clade divergences, many cryptic lineages, paraphyly at subgenus level, and sympatry of several new and formerly known lineages. Numerous specimens from mainland and insular Greece, undoubtedly the least studied region of the genus' distribution, have been included. The reconstructed phylogeny covers representative taxa and populations across the entire genus of Euscorpius. The deepest clades detected within Euscorpius correspond (partially) to its current subgeneric division, outlining subgenera Tetratrichobothrius and Alpiscorpius. The rest of the genus falls into several clades, including subgenus Polytrichobothrius and a paraphyletic subgenus Euscorpius s.s. Several cryptic lineages are recovered, especially on the islands. The inadequacy of the morphological characters used in the taxonomy of the genus to delineate species is discussed. Finally, the time frame of differentiation of Euscorpius in the study region is estimated and the distributional patterns of the lineages are contrasted with those of other highly diversified invertebrate genera occurring in the study region. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110 , 728–748.  相似文献   

5.
Sequences from the ribosomal DNA internal transcribed spacer‐2 (ITS‐2) were compared among species of Sargassaceae including the genera Sargassum and Hizikia. Species of different subgenera and sections of Sargassum were used to assess the taxonomic relationships within the genus, especially the subdivisions of the subgenus Bactrophycus. Sequences were aligned in accordance with their common secondary structure. Phylogenetic trees were constructed using neighbor‐joining, maximum likelihood and maximum parsimony methods with three species of Turbinaria as outgroups. The resulting phylogenetic trees showed that the genus Sargassum is divided into three clades corresponding to the subgenera Phyllotrichia, Sargassum and Bactrophycus. This last subgenus is further divided into four distinct groups: a Spongocarpus clade, a Teretia clade, a Hizikia clade, and a Halochloa/ Repentia clade. The position of the section Phyllo‐cystae, excluded from the subgenus Bactrophycus and included within the subgenus Sargassum is once again confirmed by the present study. Current results strongly support the assignation of Hizikia fusiformis to the genus Sargassum. Based on morphological differences and a distinct position in the molecular trees, Hizikia should be recognized as a section in the subgenus Bactrophycus so that Hizikia (Okamura) Yoshida, stat. nov. is proposed. A remarkably low divergence of ITS‐2 sequences was observed for the species in the sections Repentia and Halochloa, suggesting very recent radiation of these species. The subgenus Sargassum is divided into three clades corresponding to the three known sections: Acanthocarpicae, Malacocarpicae and Zygocarpicae, previously recognized by the morphology of receptacles. The position of Sargassum duplicatum, S. carpophyllum, S.yendoi, S. piluliferum and S. patens within the subgenus Sargassum is discussed.  相似文献   

6.
The systematics and phylogeny of the genus Arenaria and allied genera are unresolved. The use of morphological data has resulted in contradictory taxonomic concepts in the past due to their homoplastic nature. We present a phylogenetic analysis based on internal transcribed spacer (ITS) and rps16 sequence data of 140 (132 taxa) and 131 (120 taxa) accessions, respectively. Maximum parsimony and Bayesian analyses of each marker produced nearly congruent trees. Monophyly of Arenaria s.s. and Eremogone is confirmed here. Our results corroborate earlier results indicating that Arenaria subgenus Odontostemma is monophyletic, but outside the core group of Arenaria. Arenaria subgenus Solitaria is sister to Odontostemma and also not closely related to the latter; both of these subgenera are excluded from Arenaria and treated as distinct genera. The molecular data indicate that the ‘Arenaria s.s. clade’ consists of a few well‐supported subgroups and that the current subgeneric classification of the genus does not reflect evolutionary history. Arenaria subgenus Leiosperma is clearly monophyletic, but we reduce it to sectional level. Our molecular data show that the monotypic Arenaria subgenera Porphyrantha and Arenariastrum are nested in A. subgenus Arenaria, whereas subgenus Eremogoneastrum is included in Eremogone. None of the species‐rich sections in subgenus Arenaria is monophyletic. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 178 , 648–669.  相似文献   

7.
Chloroplast DNA (cpDNA) restriction site variation was examined in 32 species, representing five subgenera, of Bromus (Poaceae). Thirty-seven phylogenetically informative restriction sites were detected. Cladistic analysis of the restriction site data produced a single most-parsimonious tree of 50 steps. The cladogram indicated two major clades within the genus. One clade included B. trinii of subgenus Neobromus and species of subgenus Ceratochloa. The other was composed of subgenera Festucaria, Stenobromus, and Bromus. Within the second clade, species of subgenus Festucaria appeared in three lineages. The second clade also contained an assemblage of species belonging to subgenera Stenobromus and Bromus in a separate lineage. There was very little resolution of relationships in this assemblage since several species appeared individually in separate lineages. The cpDNA phylogenetic hypothesis did not separate species of subgenera Stenobromus and Bromus into well-defined clades as circumscribed by morphology and cytogenetics. The cpDNA tree is in agreement with the phylogenetic scheme based on traditional data in that: 1) subgenera Neobromus and Ceratochloa were the first to diverge, while Bromus and Stenobromus diverged later; 2) within the genus Bromus species with small chromosomes are ancestral; and 3) subgenera Bromus and Stenobromus probably originated from similar ancestors as Festucaria. The tree based on cpDNA data does not support that: 1) subgenera Neobromus and Ceratochloa did not have a common origin; 2) subgenus Festucaria is monophyletic; and 3) subgenera Stenobromus and Bromus are distinct entities. The mean nucleotide sequence divergence values between pairs of subgenera ranged from p = 0.0 to 0.9. These values suggest that cpDNA evolution in Bromus is slow.  相似文献   

8.
Abstract. We investigated the phylogeny and taxonomy of the Prenolepis genus‐group, a clade of ants we define within the subfamily Formicinae comprising the genera Euprenolepis, Nylanderia, gen. rev. , Paraparatrechina, gen. rev. & stat. nov. , Paratrechina, Prenolepis and Pseudolasius. We inferred a phylogeny of the Prenolepis genus‐group using DNA sequence data from five genes (CAD, EF1αF1, EF1αF2, wingless and COI) sampled from 50 taxa. Based on the results of this phylogeny the taxonomy of the Prenolepis genus‐group was re‐examined. Paratrechina (broad sense) species segregated into three distinct, robust clades. Paratrechina longicornis represents a distinct lineage, a result consistent with morphological evidence; because this is the type species for the genus, Paratrechina is redefined as a monotypic genus. Two formerly synonymized subgenera, Nylanderia and Paraparatrechina, are raised to generic status in order to provide names for the other two clades. The majority of taxa formerly placed in Paratrechina, 133 species and subspecies, are transferred to Nylanderia, and 28 species and subspecies are transferred to Paraparatrechina. In addition, two species are transferred from Pseudolasius to Paraparatrechina and one species of Pseudolasius is transferred to Nylanderia. A morphological diagnosis for the worker caste of all six genera is provided, with a discussion of the morphological characters used to define each genus. Two genera, Prenolepis and Pseudolasius, were not recovered as monophyletic by the molecular data, and the implications of this result are discussed. A worker‐based key to the genera of the Prenolepis genus‐group is provided.  相似文献   

9.
Drosophila is the genus responsible for the birth of experimental genetics, but the taxonomy of drosophilids is difficult because of the overwhelming diversity of the group. In this study, we assembled sequences for 358 species (14 genera, eight subgenera, 57 species groups, and 65 subgroups) to generate a maximum‐likelihood topology and a Bayesian timescale. In addition to sampling an unprecedented diversity of Drosophila lineages, our analyses incorporated a geographical perspective because of the high levels of endemism. In our topology, Drosophila funebris (Fabricius, 1787) (the type species of Drosophila) is tightly clustered with the pinicola subgroup in a North American clade within subgenus Drosophila. The type species of other drosophilid genera fall within the Drosophila radiation, presenting interesting prospects for the phylogenetic taxonomy of the group. Our timescale suggests that a few drosophilid lineages survived the Cretaceous–Palaeogene (K‐Pg) extinction. The drosophilid diversification began during the Palaeocene in Eurasia, but peaked during the Miocene, an epoch of drastic climatic changes. The most recent common ancestor of the clades corresponding to subgenera Sophophora and Drosophila lived approximately 56 Mya. Additionally, Hawaiian drosophilids diverged from an East Asian lineage approximately 26 Mya, which is similar to the age of the oldest emerging atoll in the Hawaiian–Emperor Chain. Interestingly, the time estimates for major geographical splits (New World versus Asia and Africa versus Asia) were highly similar for independent lineages. These results suggest that vicariance played a significant role in the radiation of fruit flies. © 2013 The Linnean Society of London  相似文献   

10.
Three new butenolides, caulerpalide A and a pair of enantiomers, (+)‐caulerpalide B and (?)‐caulerpalide B, together with seven known compounds, have been isolated from the green alga Caulerpa racemosa var. turbinata. All these structures were determined by spectroscopic techniques. The absolute configurations of caulerpalide A, (+)‐caulerpalide B and (?)‐caulerpalide B were elucidated by the method of ECD calculation. This is the first separation of butenolides from the algae of genus Caulerpa. Additionally, the antibacterial activities of the nine isolated compounds were also evaluated.  相似文献   

11.
In the present study, we investigated the intrageneric and intergeneric phylogenetic relationships of the heterotrophic marine dinoflagellate genus Protoperidinium. Using single‐cell polymerase chain reaction methods, we determined small subunit ribosomal RNA gene sequences for 10 Protoperidinium species belonging to four sections and two subgenera. Phylogenetic trees were constructed using maximum parsimony, neighbor joining and maximum likelihood methods. We found intraspecific variability of small subunit rDNA sequences in Protoperidinium conicum (Gran) Balech, Protoperidinium crassipes (Kofoid) Balech and Protoperidinium denticulatum (Gran et Braarud) Balech, but not in other species. The small subunit rDNA phylogeny revealed that the genus is monophyletic, but its phylogenetic position within the Dinophyceae could not be determined because of ambiguous basal topologies. Within the genus Protoperidinium, species of the subgenus Archaeperidinium with two anterior intercalary plates (2a) were shown to be monophyletic, but species of the subgenus Protoperidinium with three anterior intercalary plates (3a) were resolved as paraphyletic. The sections Avellana, Divergentia and Protoperidinium were shown to be monophyletic, while the section Conica was paraphyletic. Based on the trees obtained in the present study, most of the traditionally defined sections are supported by molecular phylogeny. It was also indicated that the section Avellana evolved from one of the Conica‐type dinoflagellates.  相似文献   

12.
Thanwisai A  Kuvangkadilok C  Baimai V 《Genetica》2006,128(1-3):177-204
The sequences of the second internal transcribed spacer (ITS2) of ribosomal DNA (rDNA) were determined for 40 black fly species from Thailand, belonging to 4 subgenera of the genus Simulium, namely Gomphostilbia (12 species), Nevermannia (5 species), Montisimulium (1 species), Simulium sensu stricto (21 species), and an unknown subgenus with one species (Simulium baimaii). The length of the ITS2 ranged from 247 to 308 bp. All black fly species had high AT content, ranging from 71 to 83.8%. Intraindividual variation (clonal variation) occurred in 13 species, ranging from 0.3 to 1.1%. Large intrapopulation and interpopulation heterogeneities exist in S. feuerboni from the same and different locations in Doi Inthanon National Park, northern Thailand. Phylogenetic relationships among 40 black fly species were examined using PAUP (version 4.0b10) and MrBAYS (version 3.0B4). The topology of the trees revealed two major monophyletic clades. The subgenus Simulium and Simulium baimaii were placed in the first monophyletic clade, whereas the subgenera Nevermannia + Montisimulium were placed as the sister group to the subgenus Gomphostilbia in the second monophyletic clade. Our results suggest that S. baimaii belongs to the malyschevi-group or variegatum-group in the subgenus Simulium. The molecular phylogeny generally agrees with existing morphology-based phylogenies.  相似文献   

13.
Diversification of avifaunas associated with savannah and steppes appears to correlate with open habitats becoming available, starting in the Miocene. Few comparative analyses exist for families for which all species are predominantly adapted to these habitats. One such group is Laniidae (Passeriformes), which are small‐ to medium‐sized predatory passerines known for their distinctive behaviour of impaling prey. We used multispecies coalescent‐based and concatenation methods to provide the first complete species‐level phylogeny for this group, as well as an estimate of the timing of diversification. Our analyses indicate that Laniidae as currently delimited is not monophyletic, as the genus Eurocephalus is not closely related to the remaining species. The two species currently assigned to the monotypic genera Urolestes and Corvinella are part of the same clade as the Lanius species, and we propose that they are included in the genus Lanius, making Laniidae monogeneric. The initial diversification of the clade is inferred to have occurred very rapidly, starting about 7.2–9.1 million years ago, timing depending on calibration method, but in either case coinciding with the expansion of C4 grasses. An African origin is inferred in the biogeographic analysis. In the redefined Laniidae, cooperative breeding is inferred to be restricted to a single clade, characterized by gregarious behaviour and rallying. Migratory behaviour evolved multiple times within the family.  相似文献   

14.
Eremias, or racerunners, is a widespread lacertid genus occurring in China, Mongolia, Korea, Central Asia, Southwest Asia and Southeast Europe. It has been through a series of taxonomic revisions, but the phylogenetic relationships among the species and subgenera remain unclear. In this study, a frequently studied region of the mitochondrial 16S rRNA was used to (i) reassess the phylogenetic relationships of some Eremias species, (ii) test if the viviparous species form a monophyletic group, and (iii) estimate divergence time among lineages using a Bayesian relaxed molecular-clock approach. The resulting phylogeny supports monophyly of Eremias sensu Szczerbak and a clade comprising Eremias, Acanthodactylus and Latastia. An earlier finding demonstrating monophyly of the subgenus Pareremias is corroborated, with Eremias argus being the sister taxon to Eremias brenchleyi. We present the first evidence that viviparous species form a monophyletic group. In addition, Eremias przewalskii is nested within Eremias multiocellata, suggesting that the latter is likely a paraphyletic species or a species complex. Eremias acutirostris and Eremias persica form a clade that is closely related to the subgenus Pareremias. However, the subgenera Aspidorhinus, Scapteira, and Rhabderemias seem not to be monophyletic, respectively. The Bayesian divergence-time estimation suggests that Eremias originated at about 9.9 million years ago (with the 95% confidence interval ranging from 7.6 to 12 Ma), and diversified from Late Miocene to Pleistocene. Specifically, the divergence time of the subgenus Pareremias was dated to about 6.3 million years ago (with the 95% confidence interval ranging from 5.3 to 8.5 Ma), which suggests that the diversification of this subgenus might be correlated with the evolution of an East Asian monsoon climate triggered by the rapid uplift of the Tibetan Plateau approximately 8 Ma.  相似文献   

15.
Both nuclear ribosomal ITS and chloroplast trnL-F sequences were acquired for 57 species (accessions) of Lysimachia and its close relatives, and were analyzed together with sequences retrieved from databases. The results of phylogenetic analyses based on these data (separately or combined) show that Lysimachia is paraphyletic, with the monotypic genus Glaux nested deeply inside. Previous suggestions that Anagallis and Trientalis could be ingroups of Lysimachia were not corroborated by our results. The molecular phylogenies do not support the current infrageneric divisions of Lysimachia. Subgenus Lysimachia contains at least five independent lineages. The Hawaii endemic subgenus Lysimachiopsis was shown to group with subgenera Palladia and Heterostylandra, instead of subgenus Idiophyton as previously suggested. The two North American representatives of Lysimachia, subgenus Seleucia and section Verticillatae of subgenus Lysimachia are group together as the most basal clade of the genus. Parallel and independent evolutions were inferred for morphological characters that were previously used as diagnostic criteria. Molecular phylogenies do not offer clear inferences on the overall historical biogeography of Lysimachia, but Southeast Asia origins of several clades, including the Hawaiian endemic clade and the Iberian Lysimachia ephemerum are strongly supported.  相似文献   

16.
The internal transcribed spacer (ITS1, 5.8S rDNA, and ITS2) region of nuclear ribosomal DNA (nrDNA) was sequenced from 53 species, which represent most of the living species diversity in the genus Phalaenopsis (Orchidaceae). A phylogeny was developed for the genus based on the neighbor-joining and maximum parsimony analyses of molecular data. Results of these analyses provided support for the monophyly of the genus Phalaenopsis and concurred in that the genera Doritis and Kingidium should be treated as being parts of the genus Phalaenopsis as suggested by Christenson (2001). Within the genus Phalaenopsis, neither subgenera Aphyllae nor Parishianae were monophyletic, and they were highly clustered with subgenus Proboscidioides plus sections Esmeralda and Deliciosae of subgenus Phalaenopsis based on ITS data. Those species also have the same characters of morphology of four pollinia and similar biogeographies. Furthermore, neither subgenus Phalaenopsis nor Polychilos was monophyletic. Within the subgenus Phalaenopsis, only section Phalaenopsis was highly supported as being monophyletic. As for the subgenus Polychilos, only section Polychilos was moderately supported as being monophyletic. In conclusion, the present molecular data obtained from the ITS sequence of nrDNA of the genus Phalaenopsis provide valuable information for elucidating the phylogeny of this genus.  相似文献   

17.
A molecular phylogeny and lineage age estimates are presented for the Macaronesian representatives of the weevil subfamily Cryptorhynchinae, using two mitochondrial genes (cytochrome c oxidase subunit 1 and 16S). The Bayesian reconstruction is supplemented by observations on morphology, ecology, and reproductive biology. The present study often corroborates the groups previously outlined in higher‐level informal taxonomies. These and further groups are now assigned new taxonomic status. The following genera and subgenera are described (formerly Acalles): Aeoniacalles gen. nov. , Canariacalles gen. nov. , Ficusacalles gen. nov. , Madeiracalles gen. nov. , Silvacalles gen. nov. (with Tolpiacalles subgen. nov. , Tagasastacalles subgen. nov. ), Sonchiacalles gen. nov. , Echiumacalles gen. nov. (monotypic), Lauriacalles gen. nov. (monotypic), and Pseudodichromacalles gen. nov. (monotypic; formerly Dichromacalles). For the western Palaearctic genus Acalles Schoenherr, 1825 the first subgenus Origoacalles subgen. nov. is described and for the genus Onyxacalles Stüben, 1999 the first subgenus Araneacalles subgen. nov. ; Paratorneuma Roudier 1956 resyn. Except for one species of Acalles (Origoacalles), all of these new higher taxa are endemic to the Macaronesian Islands. All new taxa are presented, together with their host plants and further data, in a synoptic tabular overview. Based on the results of our phylogenetic analysis, we advocate the hypothesis that the evolution of the species in the new genera (of which most group into a ‘Macaronesian clade’) began in the comparatively arid succulent bush zone and that the shady and humid laurel forest of the thermo‐Canarian and thermo‐Madeiran zone was entered much later. Our reconstruction implies that the Canarian and Madeiran archipelagos were colonized by Cryptorhynchinae at least seven times from the continent but saw only one considerable adaptive radiation. It also becomes apparent that it is the ancestor species of the genus Canariacalles– and not Pseudodichromacalles– that features a close connection to the south‐western European and north‐western African species of Dichromacalles s.s. Finally, a key is presented for all genera and subgenera of the Macaronesian Cryptorhynchinae. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 40–87.  相似文献   

18.
19.
We used nuclear ribosomal DNA internal transcribed spacer region (ITS 1 - 5.8S - ITS 2; ITS) sequences to generate the first phylogeny of Rubus based on a large, molecular data set. We sampled 57 taxa including 20 species of subgenus Rubus (blackberries), one to seven species from each of the remaining 11 subgenera, and the monotypic and closely related Dalibarda. In Rubus, ITS sequences are most informative among subgenera, and variability is low between closely related species. Parsimony analysis indicates that Rubus plus Dalibarda form a strongly supported clade, and D. repens may nest within Rubus. Of the subgenera with more than one species sampled, only subgenus Orobatus appears monophyletic. Three large clades are strongly supported: one contains all sampled species of nine of the 12 subgenera; another includes extreme Southern Hemisphere species of subgenera Comaropsis, Dalibarda, and Lampobatus; and a third clade consists of subgenus Rubus plus R. alpinus of subgenus Lampobatus. Rubus ursinus appears to be a hybrid between a close relative of R. macraei (subgenus Idaeobatus, raspberries) and an unidentified subgenus Rubus species. ITS sequences are generally consistent with biogeography and ploidy, but traditionally important morphological characters, such as stem armature and leaf type, appear to have limited phylogenetic value in Rubus.  相似文献   

20.
Passiflora L. has more than 575 species distributed especially in the Neotropics. The chromosome number variation in the genus is highly congruent with its main subgenera, but its basic chromosome number (x) and the underlying events responsible for this variation have remained controversial. Here, we provide a robust and well-resolved time-calibrated phylogeny that includes 102 taxa, and by means of phylogenetic comparative methods (PCM) we tested the relative importance of polyploidy and dysploidy events to Passiflora karyotype evolution and diversification. Passiflora arose 42.9 Mya, with subgenus diversification at the end of the Palaeogene (Eocene-Oligocene). The basic chromosome number of the genus is proposed as x?=?6, and a strong recent diversification found in the Passiflora subgenus (Miocene) correlated to genome size increase and a chromosome change from n?=?6 to n?=?9 by ascending dysploidy. Polyploidy, conversely, appeared restricted to few lineages, such as Astrophea and Deidamioides subgenera, and did not lead to diversification increases. Our findings suggest that ascending dysploidy provided a great advantage for generating long-term persistent lineages and promoting species diversification. Thus, chromosome numbers/genome size changes may have contributed to morphological/ecological traits that explain the pattern of diversification observed in the genus Passiflora.  相似文献   

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