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1.
Foliage and bark samples were collected from the tree that provided the type specimen for Juniperus deppeana var. sperryi Correll, as well as from trees from populations of J. pinchotii Sudw., J. flacida Schl., and J. deppeana Steud. var. deppeana. These four taxa were compared using terpenoid and morphological characters. The terpenoid data suggest that J. deppeana var. sperryi is most closely related to J. deppeana var. deppeana; no evidence of relict or present hybridization with J. flaccida was detected. The morphological data showed J. deppeana var. sperryi to be intermediate in several characters between J. deppeana var. deppeana and J. flacdda. The probability of a hybrid origin for this taxon is discussed. Due to the scattered occurrence of trees referable to J. deppeana var. sperryi, it is proposed that this taxon be reduced in rank to J. deppeana forma sperryi. 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, and Campanula, 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 that Hanabusaya is more closely allied to Adenophora than to Campanula or Symphyandra. The phylogenetic affinity of Hanabusaya and Adenophora is supported by a 100% bootstrap value and a high decay index (13). The average sequence divergence value (Kimura’s 2-parameter
method) between Hanabusaya and the Adenophora species is 2.58. The value is significantly (about ten times) lower than the ones observed between Hanabusaya and the species of Campanula (average of 23.52) and between Hanabusaya and Symphyandra (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 of Cathaya, a relic genus of the Pinaceae, was discussed based on the rbcL gene sequence. The sequence data were analysed with PAUP and MEGA programs. The great genetic distance value between Cathaya and any other genus of the Pinaceae showed that Cathaya was a distinct and isolated genus. The most parsimonious Fitch tree and neighbor-joining tree showed that Cathaya was distantly related to the clade comprising Abies, Keteleeria, Pseudolarix and Tsuga, and a sister group relationship between Cathaya and Pinus was weakly supported. Pseudotsuga is closely related to Larix. In the Abies-Keteleeria-Pseudolarix-Tsuga clade, Abies has a close relationship to Keteleeria while Pseudolarix is relatively closely related to Tsuga. 相似文献
4.
The relationship of Ambrosia (ragweed) and Franseria 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 both Ambrosia and Franseria as well as taxa from the closely related genus Hymenoclea. 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 between Ambrosia and Franseria, but indicate that the two groups are well separated. Compared to Franseria, Ambrosia is a much more strongly supported group, and the results indicate that Hymenoclea is closer to Franseria than to Ambrosia. The cpDNA phylogeny was used as a framework to examine evolutionary trends in morphology and secondary chemistry. 相似文献
5.
Bidens ctenophylla and B. 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 to B. ctenophylla, some which are similar to B. menziesii var. filiformis, and many individuals of various intermediate forms. Variation studies of greenhouse populations of the two species, the F 1 hybrid, the F 2 hybrid, and the progeny of three wild intermediates confirm the field observation that the wild intermediate population is a product of natural hybridization between B. ctenophylla and B. 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 of Chimarrhis (Condamineeae s. 1.), Bathysa (Rondeletieae), and Calycophyllum (Calycophylleae) are often misassigned to genera. The taxonomic significance of calycophylls is discussed; the generic boundaries of Chimarrhis, Bathysa, and Calycophyllum are reevaluated; and their similarities and differences are discussed. As a result, a new calycophyllous species of Chimarrhis from the Amazon, C. gentryana, is described, two of its species are transferred to Bathysa (B. Bathysoides, B. perijaënsis), and one species of Bathysa (B. difformis) is reduced to synonymy under Chimarrhis (C. turbinata). 相似文献
7.
Relationships among Calamagrostis longiseta var. longiseta, C.l. var. longe-aristata and C. 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 of C.l. longiseta, C.l. longe-aristata and C. fauriei and (2) populations showing a gradation from C.l. longiseta to C. fauriei via the intermediate C.l. longearistata and from C.l. longiseta to C.l. longe-aristata. Hybridization between C.l. longiseta and C. fauriei was estimated to be ultimately related to the geneses of the population structures detected, and it was concluded that C.l. longe-aristata must be of hybrid origin between C.l. longiseta and C. fauriei. Populations showing a gradation from C.l. longiseta to C.l. longe-aristata were regarded to have been brought about by the extinction of C. fauriei from the hybridizing population coupled with the change of environments and also by the secondary contact between C.l. longiseta and plants of C.l. longe-aristata migrating from the area that produced it. No significant reduction of pollen fertility and seed productivity was found in C.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 of C.l. longe-aristata considerably exceeds the overlapping area of the present ranges of C.l. longiseta and C. fauriei. The three taxa were deviated ecologically, and “pure” populations of C.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 that C.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.
To reveal the genetic mechanism of host selection in a monophagous fruit fly Drosophila sechellia, olfactory responses and oviposition preferences of this species were compared with those of closely related polyphagous species, D. simulans and D. melanogaster. Adult flies of D. sechellia were strongly attracted to the ripe fruit of Morinda citrifolia which is known to be the sole breeding site of this species. They were also attracted to the odor of n-caproic acid which is contained in the ripe fruit of M. citrifolia and is presumably responsible for the characteristic odor of the fruit. In contrast, D. simulans and D. melanogaster showed a strong repulsion to n-caproic acid. In parallel with the olfactory responses, D. sechellia females laid eggs preferentially on a medium containing n-caproic acid, to which the other two species showed an aversion. Genetic analyses using the hybrid progeny between D. sechellia and D. 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 genera Cardamine, Dentaria, Nasturtium, Rorippa and Armoracia ( 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 studied Dentaria species group with different Cardamine clades, and it is argued that D. bulbifera is an allopolyploid originating from a hybridization between a Cardamine and a Dentaria species. In the ITS tree, Nasturtium and Rorippa form well supported clades but their relationship to Cardamine and Armoracia remains unresolved. In the cpDNA tree, Nasturtium groups together with Cardamine. Hybridization events apparently played a role in the evolution of Nasturtium. The Cardamine/Nasturtium clade is separated from a clade placing Rorippa and Armoracia together. Armoracia is closely related to Rorippa. Analyses of the 19 Cardamine species studied revealed three main groupings, a northern hemispheric and two southern hemispheric groups. Within the northern hemisphere taxa the C. pratensis complex forms a well supported clade which seems to be closely related to C. amara, C. raphanifolia and C. flexuosa. The positions of C. hirsuta and C. 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 of Cardamine. 相似文献
10.
To examine the hybrid origin of the diploid grass Calamagrostis 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 between C. longiseta var. longiseta and C. fauriei. Previous studies have reported that some hybrids exhibit transgressive characters but others do not; the latter is the case for C. 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 in C. longiseta var. longe-aristata is that it is at an early stage of hybrid speciation. Random amplified polymorphic DNA (RAPD) analyses showed that individuals of C. longiseta var. longe-aristata were placed in both of the clusters formed by each putative parental taxon. Greater genetic diversity was observed in C. longiseta var. longe-aristata than in its putative parental taxa. All here reported findings support the scenario that C. longiseta var. longe-aristata is of hybrid origin, having evolved from C. longiseta var. longiseta and C. fauriei. 相似文献
11.
Asteropeia and Physena 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 of Asteropeia and Physena and their placement as the sister group to Caryophyllales. Many similarities were noted between Asteropeia and Physena 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 of Parmeliaceae, 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 from Parmelias. lat. Parmeliaand Parmelina, Melanelia, and Puncteliaappear as independent monophyletic groups; the type species of the two latter genera were, however, not included in the analysis. The parsimony analysis does not support Xanthoparmeliaas a monophyletic group separate from Neofuscelia, and Rimelia reticulatais nested within Parmotrema. Parmelinopsis horrescensis more closely related to Hypotrachyna revolutathan to Parmelina. Genetic distance values suggest that Flavoparmelia caperatais closer to Parmotremathan to other taxa included, and that Platismatia glaucaand Hypogymnia tubulosaare closer to Parmelias. lat. than to the Physciaceae. 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 family Parmeliaceae, 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 of Retzia, Desfontainia, and Nicodemia have been much discussed, and all three genera have been included in Loganiaceae ( Gentianales). We have made a cladistic analysis of rbcL gene sequences to determine the relationships of these taxa to Gentianales. Four new rbcL sequences are presented; i.e., of Retzia, Desfontainia, Diervilla ( Caprifoliaceae), and Euthystachys ( Stilbaceae). Our results show that Retzia, Desfontainia, and Nicodemia are not closely related to Loganiaceae or the Gentianales. Retzia is most closely related to Euthystachys and is better included in Stilbaceae. The positions of Desfontainia and Nicodemia are not settled, but Desfontainia shows affinity for the Dipsacales s.l. and Nicodemia for the Lamiales s.l. 相似文献
14.
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 Korean Ilex were analyzed in order to investigate any molecular evidence that I. × wandoensis could serve as a putative hybrid between I. cornuta and I. 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 from I. × 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 both I. cornuta and I. integra, thereby confirming I. × wandoensis is a species that was formed by crossing I. cornuta and I. integra. Lastly, the subgenus Ilex, 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 Korea Ilex, which has presented taxonomic problems previously, formed an independent clade within the consensus tree, thereby showing distinction from I. crenata.) Genetic discontinuity of I. macropoda and I. Macropoda for. pseudo-macropoda individuals couldn't be confirmed. 相似文献
16.
Xanthoria poeltii, a new species combining characters of X. candelariaand X. 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 of pcy, 222 intraspecific backcross mice were obtained by mating C57BL/6FG- pcy and Mus molossinus. Restriction fragment length polymorphism analysis of 70 of the 222 backcross progeny showed that pcy, dilute coat color ( d), and cholecystokinin ( Cck) were located in the order d—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 of d and Cck. One and eight recombinations were detected between D9Mit24 and pcy and between D9Mit16 and pcy, respectively. However, no recombinant was observed among pcy, D9Mit14, and D9Mit148. These findings strongly suggest that D9Mit14 and D9Mit148 are located near the pcy gene and are good markers for chromosomal walking to this gene. 相似文献
18.
A laboratory study was conducted on the relationships between Nosema bordati Goudegnon and Apanteles flavipes (Cameron) when they simultaneously parasitise Chilo partellus (Swinhoe). The results indicate that N. bordati is highly pathogenic to the immature instars of the parasitoid. Lightly infected adults of A. flavipes are able to transmit the Microsporidian. 相似文献
19.
Panicum amarum and P. amarulum exhibit north-south clinal variation and are virtually indistinguishable in the southern part of their range. Cytological evidence indicates that P. amarum (2 n = 54) is probably an autohexaploid derivative of P. amarulum (2 n = 36). The minor morphological differences, the apparent close genetic relationship, and the close ecological and chemical affinities between these two taxa indicate that P. amarum and P. 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 that D. ulicifolia is paraphyletic by inclusion of D. acicularis, D. arenaria and D. microcarpa. One terminal cluster is more similar to an outgroup species ( D. arthropoda) than to D. 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 subdividing D. ulicifolia into several subspecies. 相似文献
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