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1.
Robert P. Adams 《Brittonia》1973,25(3):284-289
Foliage and bark samples were collected from the tree that provided the type specimen forJuniperus deppeana var.sperryi Correll, as well as from trees from populations ofJ. pinchotii Sudw.,J. flacida Schl., andJ. deppeana Steud. var.deppeana. These four taxa were compared using terpenoid and morphological characters. The terpenoid data suggest thatJ. deppeana var.sperryi is most closely related toJ. deppeana var.deppeana; no evidence of relict or present hybridization withJ. flaccida was detected. The morphological data showedJ. deppeana var.sperryi to be intermediate in several characters betweenJ. deppeana var.deppeana andJ. flacdda. The probability of a hybrid origin for this taxon is discussed. Due to the scattered occurrence of trees referable toJ. deppeana var.sperryi, it is proposed that this taxon be reduced in rank toJ. deppeana formasperryi.  相似文献   

2.
The phylogenetic relationship of the Korean endemic genus,Hanabusaya, to other campanulaceous genera has been controversial since it was described by Nakai in 1911. Three genera of Campanuloideae,Symphyandra, Adenophora, andCampanula, have been considered closely related by various taxonomists on the basis of anther shape, gross morphology, and pollen characters, respectively. We have tested these competing taxonomic hypotheses using the internal transcribed spacer (ITS) sequences of nuclear ribosomal DNA from 12 taxa representing 7 genera of Campanulaceae. The molecular phylogeny indicates strongly thatHanabusaya is more closely allied toAdenophora than toCampanula orSymphyandra. The phylogenetic affinity ofHanabusaya andAdenophora is supported by a 100% bootstrap value and a high decay index (13). The average sequence divergence value (Kimura’s 2-parameter method) betweenHanabusaya and theAdenophora species is 2.58. The value is significantly (about ten times) lower than the ones observed betweenHanabusaya and the species ofCampanula (average of 23.52) and betweenHanabusaya andSymphyandra (24.95). The ITS sequence phylogeny suggests that some morphological characters, such as fused anthers and corolla shape, are homoplastic in the Campanulaceae genera.  相似文献   

3.
The systematic position ofCathaya, a relic genus of thePinaceae, was discussed based on therbcL gene sequence. The sequence data were analysed with PAUP and MEGA programs. The great genetic distance value betweenCathaya and any other genus of thePinaceae showed thatCathaya was a distinct and isolated genus. The most parsimonious Fitch tree and neighbor-joining tree showed thatCathaya was distantly related to the clade comprisingAbies, Keteleeria, Pseudolarix andTsuga, and a sister group relationship betweenCathaya andPinus was weakly supported.Pseudotsuga is closely related toLarix. In theAbies-Keteleeria-Pseudolarix-Tsuga clade,Abies has a close relationship toKeteleeria whilePseudolarix is relatively closely related toTsuga.  相似文献   

4.
The relationship ofAmbrosia (ragweed) andFranseria has long been debated. Their treatment as separate genera has been repeatedly challenged. In this study, chloroplast DNA restriction site variation was examined for species from bothAmbrosia andFranseria as well as taxa from the closely related genusHymenoclea. The chloroplast genomes of members of these three genera were examined using 21 restriction endonucleases and the restriction mutations were used to construct phylogenetic trees. Wagner and Dollo parsimony as well as weighted parsimony were employed to compare the different phylogenies. The results support a close relationship betweenAmbrosia andFranseria, but indicate that the two groups are well separated. Compared toFranseria, Ambrosia is a much more strongly supported group, and the results indicate thatHymenoclea is closer toFranseria than toAmbrosia. The cpDNA phylogeny was used as a framework to examine evolutionary trends in morphology and secondary chemistry.  相似文献   

5.
Bidens ctenophylla andB. menziesii var.filiformis are two heterozygous, self-fertile but outcrossing, interfertile taxa. A relatively fertile intermediate population occurs on the “hybridized habitat” of a recent lava flow. This population contains some indi viduals which are similar toB. ctenophylla, some which are similar toB. menziesii var.filiformis, and many individuals of various intermediate forms. Variation studies of greenhouse populations of the two species, the F1 hybrid, the F2 hybrid, and the progeny of three wild intermediates confirm the field observation that the wild intermediate population is a product of natural hybridization betweenB. ctenophylla andB. menziesii var.filiformis. The analysis of two interspecific characters, stem anthocyanin and achene awns, indicates that each is polygenic and is regulated by relatively few genes.  相似文献   

6.
A comparison of some genera of the Condaminecae (Rubiaceae) with a few taxa of closely related tribes (Rondeletieae, Calycophylleae, and Cinchoneae) revealed that some species ofChimarrhis (Condamineeae s. 1.),Bathysa (Rondeletieae), andCalycophyllum (Calycophylleae) are often misassigned to genera. The taxonomic significance of calycophylls is discussed; the generic boundaries ofChimarrhis, Bathysa, andCalycophyllum are reevaluated; and their similarities and differences are discussed. As a result, a new calycophyllous species ofChimarrhis from the Amazon,C. gentryana, is described, two of its species are transferred toBathysa (B. Bathysoides, B. perijaënsis), and one species ofBathysa (B. difformis) is reduced to synonymy underChimarrhis (C. turbinata).  相似文献   

7.
Relationships amongCalamagrostis longiseta var.longiseta, C.l. var.longe-aristata andC. fauriei, which are principally at the 2n=28 chromosome level, were studied mainly on the basis of population samples. The populations comprised (1) “pure” populations of each ofC.l. longiseta, C.l. longe-aristata andC. fauriei and (2) populations showing a gradation fromC.l. longiseta toC. fauriei via the intermediateC.l. longearistata and fromC.l. longiseta toC.l. longe-aristata. Hybridization betweenC.l. longiseta andC. fauriei was estimated to be ultimately related to the geneses of the population structures detected, and it was concluded thatC.l. longe-aristata must be of hybrid origin betweenC.l. longiseta andC. fauriei. Populations showing a gradation fromC.l. longiseta toC.l. longe-aristata were regarded to have been brought about by the extinction ofC. fauriei from the hybridizing population coupled with the change of environments and also by the secondary contact betweenC.l. longiseta and plants ofC.l. longe-aristata migrating from the area that produced it. No significant reduction of pollen fertility and seed productivity was found inC.l. longe-aristata. Based on the results of population analyses, the delimitation of the taxa concerned was made clearer. The examination of herbarium specimens showed that the range ofC.l. longe-aristata considerably exceeds the overlapping area of the present ranges ofC.l. longiseta andC. fauriei. The three taxa were deviated ecologically, and “pure” populations ofC.l. longe-aristata were found on several damp subalpine fields in central and northern Honshu that seemed to represent the most suitable niche for this taxon. It was estimated thatC.l. longe-aristata would evolve into a new good species if the future organism-environment interactions are favorable for it.  相似文献   

8.
Isaya Higa  Yoshiaki Fuyama 《Genetica》1993,88(2-3):129-136
To reveal the genetic mechanism of host selection in a monophagous fruit flyDrosophila sechellia, olfactory responses and oviposition preferences of this species were compared with those of closely related polyphagous species,D. simulans andD. melanogaster. Adult flies ofD. sechellia were strongly attracted to the ripe fruit ofMorinda citrifolia which is known to be the sole breeding site of this species. They were also attracted to the odor ofn-caproic acid which is contained in the ripe fruit ofM. citrifolia and is presumably responsible for the characteristic odor of the fruit. In contrast,D. simulans andD. melanogaster showed a strong repulsion ton-caproic acid. In parallel with the olfactory responses,D. sechellia females laid eggs preferentially on a medium containingn-caproic acid, to which the other two species showed an aversion. Genetic analyses using the hybrid progeny betweenD. sechellia andD. simulans suggested that the species differences in these behaviors are controlled by gene(s) located on the second chromosome.  相似文献   

9.
Representatives of the generaCardamine, Dentaria, Nasturtium, Rorippa andArmoracia (Brassicaceae) were analyzed to elucidate their phylogenetic relationships based on nuclear (ITS) and non-coding chloroplast (cp) DNA sequences.Dentaria seems to be polyphyletic. The two studiedDentaria species group with differentCardamine clades, and it is argued thatD. bulbifera is an allopolyploid originating from a hybridization between aCardamine and aDentaria species. In the ITS tree,Nasturtium andRorippa form well supported clades but their relationship toCardamine andArmoracia remains unresolved. In the cpDNA tree,Nasturtium groups together withCardamine. Hybridization events apparently played a role in the evolution ofNasturtium. TheCardamine/Nasturtium clade is separated from a clade placingRorippa andArmoracia together.Armoracia is closely related toRorippa. Analyses of the 19Cardamine species studied revealed three main groupings, a northern hemispheric and two southern hemispheric groups. Within the northern hemisphere taxa theC. pratensis complex forms a well supported clade which seems to be closely related toC. amara, C. raphanifolia andC. flexuosa. The positions ofC. hirsuta andC. impatiens are uncertain. The two southern hemisphere clades consist of New Guinean species and south-eastern Australian/Tasmanian and subantarctic species, respectively. They may reflect migration routes from the northern to the southern hemisphere, but further studies are necessary to fully understand the evolution of the bihemispheric distribution pattern ofCardamine.  相似文献   

10.
To examine the hybrid origin of the diploid grassCalamagrostis longiseta var.longe-aristata, we performed morphometric and genetic analyses of this taxon and its putative parental taxa. The morphometric analyses revealed that, in general,C. longiseta var.longe-aristata is morphologically intermediate betweenC. longiseta var.longiseta andC. fauriei. Previous studies have reported that some hybrids exhibit transgressive characters but others do not; the latter is the case forC. longiseta var.longe-aristata. Their absence may be due to the ecological adaptation to environments intermediate between those inhabited by the putative parental taxa, and therefore the transgressive characters have not been selected. Nevertheless, there is no direct evidence for adaptive value of the characters examined in this study and only a small part of all characters potentially responsible for adaptation was investigated. An alternative hypothesis about the absence of transgressive characters inC. longiseta var.longe-aristata is that it is at an early stage of hybrid speciation. Random amplified polymorphic DNA (RAPD) analyses showed that individuals ofC. longiseta var.longe-aristata were placed in both of the clusters formed by each putative parental taxon. Greater genetic diversity was observed inC. longiseta var.longe-aristata than in its putative parental taxa. All here reported findings support the scenario thatC. longiseta var.longe-aristata is of hybrid origin, having evolved fromC. longiseta var.longiseta andC. fauriei.  相似文献   

11.
Asteropeia andPhysena are both enigmatic woody dicotyledons from Madagascar. Various taxonomic affinities have been suggested for both genera, but no consensus has been reached. An analysis of rbcL sequence data strongly supports recognition of the sister-group relationship ofAsteropeia andPhysena and their placement as the sister group to Caryophyllales. Many similarities were noted betweenAsteropeia andPhysena for stem, wood, leaf, flower, pollen, and fruit characters. The most notable differences are found in the morphology of the flowers and the anatomy of the wood rays.  相似文献   

12.
New sequences have been produced of the ITS rDNA region of twenty-nine species ofParmeliaceae, and analysed by neighbour-joining maximum likelihood distance analysis, and maximum parsimony analysis. Twelve monophyletic groups have been identified, most of which correspond to proposed generic segregated fromParmelias. lat.ParmeliaandParmelina,Melanelia, andPuncteliaappear as independent monophyletic groups; the type species of the two latter genera were, however, not included in the analysis. The parsimony analysis does not supportXanthoparmeliaas a monophyletic group separate fromNeofuscelia, andRimelia reticulatais nested withinParmotrema. Parmelinopsis horrescensis more closely related toHypotrachyna revolutathan toParmelina. Genetic distance values suggest thatFlavoparmelia caperatais closer toParmotremathan to other taxa included, and thatPlatismatia glaucaandHypogymnia tubulosaare closer toParmelias. lat. than to thePhysciaceae. However, there is no conclusive support for any of the latter groupings in the parsimony analysis. We conclude that the ITS region contains valuable information for studying generic delimitations within the familyParmeliaceae, but our study suggests that this region will not conclusively resolve within-family relationships in this group.  相似文献   

13.
The taxonomic positions ofRetzia, Desfontainia, andNicodemia have been much discussed, and all three genera have been included inLoganiaceae (Gentianales). We have made a cladistic analysis ofrbcL gene sequences to determine the relationships of these taxa toGentianales. Four newrbcL sequences are presented; i.e., ofRetzia, Desfontainia, Diervilla (Caprifoliaceae), andEuthystachys (Stilbaceae). Our results show thatRetzia, Desfontainia, andNicodemia are not closely related toLoganiaceae or theGentianales. Retzia is most closely related toEuthystachys and is better included inStilbaceae. The positions ofDesfontainia andNicodemia are not settled, butDesfontainia shows affinity for theDipsacales s.l. andNicodemia for theLamiales s.l.  相似文献   

14.
Urbatsch  Lowell E.  Turner  B. L. 《Brittonia》1975,27(4):348-354

The genusSabazia is expanded to include the genusTricarpha, Calea palmeri, and several newly described taxa,S. tridacoides var.tridacoides and var.latifolia, S. palmeri var.lancifolia, andS. longiradiata. Comparative studies of several morphological features suggest thatSabazia is most clearly related toSelloa andGalinsoga. Karyological data reinforce this observation: inSelloa andGalinsoga x = 8 whereas inSabazia x = 4 andn = 4, 8, 16, or 24. Several species ofCalea are very similar toSabazia in floral features and may be of close phyletic affinity, but most species ofCalea differ conspicuously, suggesting more remote relationships. Other taxa in the Galinsoginae apparently fairly closely allied toSabazia includeOteiza andTridax.

  相似文献   

15.
In this study, internal transcribed spacer (ITS) regions within the nuclear ribosomal DNA of KoreanIlex were analyzed in order to investigate any molecular evidence thatI. × wandoensis could serve as a putative hybrid betweenI. cornuta andI. integra. We also sought to clearly identify taxonomic relationships and problems caused by consecutive external morphological characters among taxa in the genus. We sequenced 20 clones fromI. × wandoensis and found these individuals displayed intra-genomic polymorphisms within ITS regions. The analysis of the clones clearly demonstrated the presence of discrete sequences from bothI. cornuta andI. integra, thereby confirmingI. × wandoensis is a species that was formed by crossingI. cornuta andI. integra. Lastly, the subgenusIlex, which contains the evergreen species, failed to form a monophyletic group in a strict consensus tree that was prepared based upon ITS regions.I. crenata var.microphylla in the subgenus KoreaIlex, which has presented taxonomic problems previously, formed an independent clade within the consensus tree, thereby showing distinction fromI. crenata.) Genetic discontinuity ofI. macropoda andI. Macropoda for.pseudo-macropoda individuals couldn't be confirmed.  相似文献   

16.
Xanthoria poeltii, a new species combining characters ofX. candelariaandX. ulophyllodesfrom Sweden, Denmark, Germany and Hungary, is described and illustrated. Comments about its differences from related taxa are provided.  相似文献   

17.
The murine polycystic kidney disease gene,pcy, is an autosomal recessive trait located on chromosome 9. To determine the genetic locus ofpcy, 222 intraspecific backcross mice were obtained by mating C57BL/6FG-pcy andMus molossinus. Restriction fragment length polymorphism analysis of 70 of the 222 backcross progeny showed thatpcy, dilute coat color (d), and cholecystokinin (Cck) were located in the orderd—pcy—Cck from the centromere. Simple sequence repeat length polymorphism analysis of DNA of all 222 backcross mice was carried out using four markers which were located near the central regions ofd andCck. One and eight recombinations were detected betweenD9Mit24 andpcy and betweenD9Mit16 andpcy, respectively. However, no recombinant was observed amongpcy, D9Mit14, andD9Mit148. These findings strongly suggest thatD9Mit14 andD9Mit148 are located near thepcy gene and are good markers for chromosomal walking to this gene.  相似文献   

18.
A laboratory study was conducted on the relationships betweenNosema bordati Goudegnon andApanteles flavipes (Cameron) when they simultaneously parasitiseChilo partellus (Swinhoe). The results indicate thatN. bordati is highly pathogenic to the immature instars of the parasitoid. Lightly infected adults ofA. flavipes are able to transmit the Microsporidian.  相似文献   

19.
Panicum amarum andP. amarulum exhibit north-south clinal variation and are virtually indistinguishable in the southern part of their range. Cytological evidence indicates thatP. amarum (2n = 54) is probably an autohexaploid derivative ofP. amarulum (2n = 36). The minor morphological differences, the apparent close genetic relationship, and the close ecological and chemical affinities between these two taxa indicate thatP. amarum andP. amarulum should have varietal rather than specific rank.  相似文献   

20.
Daviesia ulicifolia is a widespread species that exhibits complex variation throughout its range. Using ordination and cluster analysis of morphometric characters we resolved ten terminal taxa for phylogenetic analysis. A data set including these and five closely related species was coded for a combination of morphometric and qualitative characters and analysed using parsimony. This revealed thatD. ulicifolia is paraphyletic by inclusion ofD. acicularis, D. arenaria andD. microcarpa. One terminal cluster is more similar to an outgroup species (D. arthropoda) than toD. ulicifolia and should be treated as a new species. Given recent theoretical and empirical studies showing paraphyly to be both expected and observed at species level, we propose that all existing species in this group continue to be recognised taxonomically. We suggest subdividingD. ulicifolia into several subspecies.  相似文献   

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