首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Jasminum L. (Oleaceae) consists of \(\sim 200\) species that are distributed in tropical, subtropical and temperate regions of the world. In India, this genus is represented by ca 47 species of which 16 are endemic. Based on the nuclear (internal-transcribed spacer (ITS) region of nrDNA and chloroplast markers (matK, trnL-F and trnH-psbA), phylogenetic relationships in 22 species including one variety of Jasminum in India have been assessed. Maximum likelihood and Bayesian analyses from individual markers, as well as from combined dataset, reveal that the group is monophyletic if Menodora spp. are excluded from the analyses. Our analyses recovered three strongly supported clades. Ancestral character state reconstruction of taxonomically useful characters (leaf forms, leaf arrangement and flower colour) which were used to demarcate sections within the genus reveals homoplasy. Our study suggests that after split from the last common ancestor, there have been at least four reversals to unifoliolate condition. Pinnately compound leaf form evolved at least twice and trifoliolate condition evolved one time only. Alternate leaf form evolved at least twice, once in clade 1 and once in clade 3 and all the time from ancestors having opposite leaf forms. Flower colour evolution clearly depicts that clade 1 is yellow-flowered and clades 2 and 3 have admixture of white and yellow-flowered Jasminum species. Our study suggests that yellow-flowered condition evolved from the white-flowered ancestor. The present study is first to estimate the evolutionary history of Indian Jasmines.  相似文献   

2.
Muscodor is a non-sporulating, volatile organic compounds producing endophytic fungi that has been extensively explored as a bio-fumigant and bio-preservative. Novel species of this genus have been mainly identified using ITS sequences. However, the ITS hyper-variability hinders the creation of reproducible alignments and stable phylogenetic trees. Conserved structural data of the ITS region represents as a vital auxiliary information for accurate speciation of fungi. In the present study, secondary structural data of ITS1, 5.8S, and ITS2 region of all Muscodor species were generated using LocaRNA web server. The predicted secondary structural data displayed greater variability in ITS1 region in comparison to ITS2. The structural data of all sequences exhibited characteristic conserved features of eukaryotic rRNA. Evolutionary conserved motifs were found among all 5.8S and ITS2 sequences. Profile neighbor joining (PNJ) tree based on combined sequence-structural information of ITS region was generated in ProfDists. The PNJ tree resolved into four major groups whereby M. fengyangenesis and M. albus species formed monophyletic clades. However, three M. albus species along with other Muscodor species emerged as sister branches to the existing clades, thereby, improving the precision of phylogenetic analysis for identification of novel species of Muscodor genus. Hence, the results indicated that structural analysis along with primary sequence information can provide new insights for precise identification of Muscodor species.  相似文献   

3.
Phylogenetic analyses of nuclear rDNA spacers (ITS and ETS) from Azorella and five closely related genera confirm earlier plastid results indicating that Azorella, Huanaca, Mulinum, and Schizeilema are all polyphyletic, and that the monotypic genus Laretia is nested within one of the six subclades of Azorella. Only Stilbocarpa is monophyletic, but that genus is embedded within a larger clade that includes representatives of three other genera (Azorella, Huanaca, and Schizeilema). Both nuclear and plastid datasets identify the same 10 clades, but the placement of these clades remains unstable. A new classification is presented in which these six genera are reduced to a single genus (Azorella) comprising 58 species arranged in 10 sections, one of which is newly described here (Azorella sect. Ranunculus), and one lectotypified (Azorella sect. Glabratae). A total of 13 new combinations are made (A. albovaginata, A. allanii, A. boelckei, A. burkartii, A. colensoi, A. echegarayi, A. echinus, A. hallei, A. lyallii, A. polaris, A. prolifera, A. robusta, A. ulicina), along with three replacement names (A. atacamensis, A. ruizii, A. schizeilema). For each of the 58 accepted species, a full synonymy is provided along with geographic ranges (and nomenclatural notes, where useful).  相似文献   

4.
The phylum Neocallimastigomycota contains eight genera (about 20 species) of strictly anaerobic fungi. The evolutionary relationships of these genera are uncertain due to insufficient sequence data to infer their phylogenies. Based on morphology and molecular phylogeny, thirteen isolates obtained from yak faeces and rumen digesta in China were assigned to Neocallimastix frontalis (nine isolates), Orpinomyces joyonii (two isolates) and Caecomyces sp. (two isolates), respectively. The phylogenetic relationships of the eight genera were evaluated using complete ITS and partial LSU sequences, compared to the ITS1 region which has been widely used in this phylum in the past. Five monophyletic lineages corresponding to six of the eight genera were statistically supported. Isolates of Caecomyces and Cyllamyces were present in a single lineage and could not be separated properly. Members of Neocallimastigomycota with uniflagellate zoospores represented by Piromyces were polyphyletic. The Piromyces-like genus Oontomyces was consistently closely related to the traditional Anaeromyces, and separated the latter genus into two clades. The phylogenetic position of the Piromyces-like genus Buwchfawromyces remained unresolved. Orpinomyces and Neocallimastix, sharing polyflagellate zoospores, were supported as sister genera in the LSU phylogeny. Apparently ITS, specifically ITS1 alone, is not a good marker to resolve the generic affinities of the studied fungi. The LSU sequences are easier to align and appear to work well to resolve generic relationships. This study provides a comparative phylogenetic revision of Neocallimastigomycota isolates known from culture and sequence data.  相似文献   

5.
The genus Scutellaria (Lamiaceae, Scutellarioidae) includes taxa with a wide range of pharmacological traits, which make this genus economically important. Previous taxonomical studies on Scutellaria were mainly based on morphological and chromosomal characters. The infrageneric classification of the genus has been the subject of a long controversy among authors, and delimitation of taxa remains problematic. In this study, the phylogeny of the genus was evaluated using nrDNA ITS and trnL-F sequences, with a focus on the 42 Iranian taxa belonging to subgenera Apeltanthus and Scutellaria. In both ITS and trnL-F trees, there were two main clades within the genus corresponding to the two subgenera Scutellaria and Apeltanthus. In the subg. Scutellaria, the sect. Anaspis was monophyletic, but the monophyly of sect. Scutellaria was not supported. In this subgenus, S. galericulata was located away from other species in both trees, supported the isolation of this species from the sect. Scutellaria and inclusion in the sect. Galericularia as was previously considered by some authors. In subg. Apeltanthus, sect. Apeltanthus and sect. Lupulinaria were not monophyletic; furthermore, the monophyly of subsect. Lupulinaria was not supported. Based on the results of this study, it can be suggested that the sectional classification of both subgenera Apeltanthus and Scutellaria should be revised.  相似文献   

6.
Sequence variability of the ITS spacers and 5.8S rRNA gene was examined in 11 accessions of the subfamily Scilloideae, including seven accessions of rare and endangered species Bellevalia sarmatica from Volgograd region. The intraspecific polymorphism level of the examined ITS1–5.8S–ITS2 sequence of B. sarmatica accessions constituted 1.3%. The phylogenetic position of B. sarmatica within the genus Bellevalia was determined. It was demonstrated that B. sarmatica belonged to the section Nutantes, and the most closely related species were B. webbiana and B. dubia. Nucleotide substitutions in the 5.8S rRNA gene sequence of the analyzed Scilloideae accessions were identified and studied. The predicted secondary structure of 5.8S rRNA gene was constructed. It was demonstrated that in the examined accessions, mutations in the 5.8S rRNA gene were mainly localized in the third hairpin region and had no effect on the secondary structure of the 5.8S rRNA molecule.  相似文献   

7.
In the legume genus Senna, series Aphyllae includes seven species of leafless shrubs and subshrubs from arid, semiarid and xerophilous areas of three different biogeographic subregions in southern South America. In this study, we investigated the evolutionary history of Aphyllae in a molecular phylogenetic framework. We reconstructed phylogenetic relationships among Aphyllae species based on DNA sequence data of four plastid (rpS16, rpL16, matK, trnL-F) and one nuclear (ITS) region from 23 accessions, analyzed with parsimony, Bayesian and maximum likelihood methods. We inferred the evolutionary and biogeographic history estimating divergence times and reconstructing ancestral character states and ancestral areas of distribution. Series Aphyllae was found to be monophyletic, and the taxa formed two main clades: Clade A gathering S. aphylla var. aphylla, S. crassiramea, S. rigidicaulis and S. spiniflora; and Clade B grouping S. acanthoclada, S. aphylla var. divaricata, S. aphylla var. pendula and S. pachyrrhiza. The morphologically complex S. aphylla appears thus polyphyletic. Molecular dating and ancestral area reconstructions suggest that the Aphyllae clade started to diversify in the South American Transition Zone in the Late Pliocene. Based on these results, we hypothesize that this diversification occurred during the last period of Andean uplift with the aridification in South America. The ancestral character state reconstructions suggest that, in addition to the loss of leaves in adult plants, series Aphyllae evolved various morphological features, such as fastigiate, thickened or decumbent–subdecumbent branches during the colonization and establishment in different arid and semiarid lands in South America.  相似文献   

8.
Geologic events promoting the aridization of southern South America contributed to lineage divergences and species differentiation through geographic (allopatric divergence) and biotic and abiotic factors (ecological divergence). For the genus Anarthrophyllum, which is distributed in arid and semi-arid regions of Patagonia, we assessed how these factors affected species diversification and reconstructed its possible biogeographic history in South American arid environments. Sequences were obtained from two molecular markers: the ITS nuclear region and the trnS-trnG plastid region. Using Parsimony, Maximum likelihood and Bayesian inference individual gene trees were reconstructed, and a species tree was obtained using multi-species coalescent analysis. Divergence times among species were estimated using secondary calibrations. Flexible Bayesian models and stochastic character mapping were used to elucidate ancestral geographic distributions and the evolution of the floral and vegetative phenotypes in the genus. Gene trees and species tree analyses strongly support Anarthrophyllum as monophyletic; all analyses consistently retrieved three well-supported main clades: High Andean Clade, Patagonian Clade 1, and Patagonian Clade 2. Main diversification events occurred concomitant with the Andean uplift and steppe aridization; the Andean mountain range possibly acted as a species barrier for the High Andean Clade. Vegetative traits showed adaptations to harsh climates in some clades, while pollinator-related floral features were associated with independent diversification in bee- and bird-pollinated clades within both Patagonian Clades. In conclusion, evolutionary and biogeographic history of Anarthrophyllum resulted from the action of ecological, historical, and geographic factors that acted either alternatively or simultaneously.  相似文献   

9.
Birch trees inhabiting the high-altitude Hyrcanian forest (the southern shores of the Caspian Sea of Iran and Azerbaijan) are classified in the EN (endangered) category of the International Union for Conservation of Nature (IUCN). Taxonomic status and phylogenetic relationship of Iranian populations, molecular taxonomy, and biogeography of the genus Betula in the world have been considered. Four remnant populations of Betula were selected from north and northwestern parts of Iran. The internal ITS and trnH-psbA intergenic spacer regions were sequenced. Based on the trnH-psbA and ITS, Iranian birch and white birch were placed in a clade, but based on trnH-psbA divided into two subclades. Phylogenetic trees based on ITS and trnH-psbA data did not completely support the morphological classification. Network analysis confirms a close relationship of B. pendula with B. platyphylla and B. papyrifera with B. humilis, and B. ermanii were in a group with the other tetraploid species of the subgenus Neurobetula. Divergence time analysis showed that about 75 Ma ago the Betula genus separated from the other genus of Betulaceae and then divided into two main clades in Oligocene. Our divergence analysis supports that two subgenera of Betulenta and Betulaster are the oldest subgenera in the genus Betula and they date back to Eocene. The ancestral reconstruction suggests that ancestors of the genus Betula originated from Southeast Asia.  相似文献   

10.
To study the phylogenetic relationships, evolutionary history, and molecular systematics of firs (genus Abies), the phylogenetic reconstruction, based on nuclear multilocus markers—amplified fragment length polymorphism (AFLP)—was conducted. Using seven combinations of selective primers, 84 samples of 39 taxa were genotyped for 553 polymorphic AFLP loci. A comparison with our earlier chloroplast and mitochondrial phylogenies of the genus (in 2014) shows that the nuclear phylogeny generally is more congruent to the chloroplast tree. Most of the clades resolved by the chloroplast phylogeny were supported also in the AFLP tree. Employing the nuclear DNA-based tree, we revealed the presence of new groups and the differences in the topology of several clades. AFLP confirmed the monophyly of Asian species of section Balsamea and their sister position in relation to the American group of species of this section. As shown by the tree of chloroplast DNA, Asian species of section Balsamea do not form a monophyletic group, but belong to the clade comprising the majority of Asian species. Phylogenetically mitochondrial DNA data to a large extent are not congruent to the nuclear and chloroplast DNA trees, and are more in line with geographical distribution of species. Conflicts between nuclear and cytoplasmic phylogeny were analyzed. Taking them into account, we consider the hypothesis of a hybrid origin of particular groups of firs, including ancient hybridization in section Balsamea. A comparison of molecular data with traditional taxonomy of the genus is discussed.  相似文献   

11.
The nucleotide sequences of the nuclear rDNA ITS regions were determined for 34 species of the genus Primula L. and one species of the genus Cortusa L., family Primulaceae Vent., and used to infer the phylogenetic relationships among these species. In this analysis species of the Russian flora and the flora of adjacent territories were studied for the first time. The results clarified the taxomic structure of the genus Primula and confirmed the entity of some of its sections; but not the subgenera sensu J.Richards. Our data do not support an independent status of the genus Cortusa, placing it as one of the terminal lineages of the section Cortusoides Balf. f. in the genus Primula.  相似文献   

12.
13.
The study of cryptic species allows to describe and to understand biodiversity, and the evolutionary processes shaping it. Mites of the family Rhinonyssidae are permanent parasites of the nasal cavities of birds, currently including about 500 described species and 12 genera. Here, we tested the hypothesis that mites from five populations of the genus Tinaminyssus—three isolated from European turtle doves (Streptopelia turtur), and two from Eurasian collared doves (Streptopelia decaocto; Aves: Columbiformes)—are, in fact, two cryptic species inhabiting different hosts. First, we performed a morphometrical study on 16 traits. Then, we used the ITS1-5.8S rDNA-ITS2 nuclear region (ITS region), and a fragment of the mitochondrial cytochrome c-oxidase 1 (COI) to carry out phylogenetic and species delimitation analyses on Tinaminyssus species. Morphological analyses revealed a lack of biometric differentiation among Tinaminyssus populations from the two host species. However, molecular analyses indicated a high degree of genetic differentiation between populations of Tinaminyssus sp. from S. turtur and S. decaocto. Overall, results show that they can be considered as different cryptic species, suggesting a case of evolutionary stasis, likely because of the anatomical similarity between closely-related bird host species.  相似文献   

14.
Stenotopic specialization to a fragmented habitat promotes the evolution of genetic structure. It is not yet clear whether small-scale population structure generally translates into large-scale intraspecific divergence. In the present survey of mitochondrial genetic structure in the Lake Tanganyika endemic Altolamprologus (Teleostei, Cichlidae), a rock-dwelling cichlid genus comprising A. compressiceps and A. calvus, habitat-induced population fragmentation contrasts with weak phylogeographic structure and recent divergence among genetic clades. Low rates of dispersal, perhaps along gastropod shell beds that connect patches of rocky habitat, and periodic secondary contact during lake level fluctuations are apparently sufficient to maintain genetic connectivity within each of the two Altolamprologus species. The picture of genetic cohesion was interrupted by a single highly divergent haplotype clade in A. compressiceps restricted to the northern part of the lake. Comparisons between mitochondrial and nuclear phylogenetic reconstructions suggested that the divergent mitochondrial clade originated from ancient interspecific introgression. Finally, ‘isolation-with-migration’ models indicated that divergence between the two Altolamprologus species was recent (67–142 KYA) and proceeded with little if any gene flow. As in other rock-dwelling cichlids, recent population expansions were inferred in both Altolamprologus species, which may be connected with drastic lake level fluctuations.  相似文献   

15.
Maximum parsimony and maximum likelihood phylogenetic trees were constructed for 21 taxa of Lophozia s. str. and the related genera, Schistochilopsis (5 species), Protolophozia elongata, and Obtusifolium obtusum based on combined nuclear ITS1-2 and chloroplast trnL-F DNA sequences. The trees were characterized by similar topology. It was demonstrated that the genus Lophozia s. str. was monophyletic, excluding L. sudetica, which deserved isolation into a distinct cryptic genus. The species distribution among the clades disagreed with the sections distinguished based on anatomical and morphological data. The relationships within the genus Schistochilopsis were consistent with the sectioning of the genus, based on morphological characters. Analysis of molecular data provided more precise definition of the systematic position of a number of taxa. A low level of genetic divergence of geographically distant forms was demonstrated.  相似文献   

16.
Rinorea, the second most species-rich genus in the Violaceae, has been shown to be polyphyletic with four separate clades recovered in phylogenetic studies. Among these clades is the Rinorea crenata group, which is composed of three Neotropical species. This group has been shown in family- and genus-level molecular phylogenies to be resolved outside of a large clade representing Rinorea s.str. Based on phylogenetic, morphological, and anatomical evidence, Bribria, a new genus, is segregated from Rinorea s.str. and described, with new combinations made for its three species: Bribria apiculata, Bribria crenata, and Bribria oraria. In addition, two new sections in Rinorea s.str. are described to accommodate the remaining Neotropical species: Rinorea sect. Rinorea and Rinorea sect. Pubiflora, which correspond to Group IIa Rinorea and Group IIc Pubiflora, respectively, in W. H. A. Hekking’s monograph of Neotropical Rinorea.  相似文献   

17.
The relationship between Sporidiobolus johnsonii and S. salmonicolor was investigated using rDNA sequence data. Two statistically well-supported clades were obtained. One clade included the type strain of S. johnsonii and the other included the type strain of S. salmonicolor. However, some mating strains of S. salmonicolor were found in the S. johnsonii group. These strains belonged to mating type A2 and were sexually compatible with mating type A1 strains from the S. salmonicolor group. DNA–DNA reassociation values were high within each clade and moderate between the two clades. In the re-investigation of teliospore germination, we observed that the basidia of S. salmonicolor were two-celled. In S. johnsonii, basidia were not formed and teliospore germination resulted in direct formation of yeast cells. We hypothesize that the S. johnsonii clade is becoming genetically isolated from the S. salmonicolor group and that a speciation process is presently going on. We suspect that the observed sexual compatibility between strains of the S. johnsonii and S. salmonicolor groups and the possible genetic flow between the two species has little biological relevance because distinct phenotypes have been fixed in the two taxa and intermediate (hybrid) sequences for LSU and ITS rDNAs have not been detected.  相似文献   

18.
The causal agents of witches' broom of bamboo plants in East Asia, Epichloë bambusae and E. sasae, were morphologically and phylogenetically examined. The phylogenetic studies were conducted using ITS 1, 2, and 5.8 S rDNA regions. Both Epichloë species produce Ephelis-type conidia in artificial medium and are phylogenetically situated in different clades from Epichloë and Parepichloë. Here, we propose a new genus Heteroepichloë for these two bambsicolous Epichloë species.  相似文献   

19.
The genus Otidea was recently monographed and studied phylogenetically, but knowledge of the diversity and distribution of Otidea species in China is fragmentary. In this study, collections from China were examined morphologically and included in phylogenetic analyses. Using LSU, TEF1-α, and RPB2 new species were placed within previously recognized clades in the genus. The results agree with both Genealogical Concordance Phylogenetic Species Recognition (GCPSR) and genetic divergence as previously reported. Three new species, Otidea hanseniae, Otidea korfii and Otidea purpureogrisea are recognized based on phylogenetic reconstruction using ITS, LSU, TEF1- α and RPB2. Comments on some incompletely known species are added. With the discovery of these three new species, the genus Otidea in China proves to be more diverse than previously recognized.  相似文献   

20.
The genus Jatropha (Euphorbiaceae) contains species that are of significant economic and ornamental value. However, Jatropha breeding material is rather limited due to incomplete information regarding phylogenetic relationships among germplasm resources. Phylogenetic analyses were performed based on the internal transcribed spacer of nuclear ribosomal DNA (nrDNA ITS), two chloroplast regions (trnL-F and rbcL), and the combined (ITS+trnL-F+rbcL) dataset among twenty-five specimens representing six key Jatropha species. Phylogenetic relationships of Jatropha were well resolved between subgenus Curcas and subgenus Jatropha, and demonstrated the intermediate position of section Polymorphae among sections of both subgenera. Jatropha curcas and J. integerrima demonstrated a close phylogenetic relationship. The molecular data agreed with the morphological classification that recognized J. multifida and J. podagrica in sec. Peltatae. The distinct intraspecific divergence that occurred in J. curcas could be attributed to restricted gene flow caused by geographical isolation and different ecological conditions. Phylograms produced with trnL-F and rbcL sequence data suggested slow rates of sequence divergence among Jatropha spp., while the ITS gene tree had good resolution suggesting high genetic variation of ITS among Jatropha species.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号