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1.
Yamuna Narayanan 《Genetics》1973,73(2):319-350
The phylogenetic relationships among the species of the D. robusta group were investigated by the analysis of chromosomal differences. Six of the ten known members of the D. robusta group were available for the study: D. colorata and D. robusta from the United States, and D. sordidula, D. pseudosordidula, D. lacertosa, and D. moriwakii from Japan. Analysis of the metaphase chromosomes from larval ganglion cells suggests that D. moriwakii and D. colorata, with rod-shaped X-chromosomes, are the more ancestral species, while D. sordidula, D. pseudosordidula, D. robusta, and D. lacertosa, with V-shaped X-chromosomes, are derived. The ancestral position of D. colorata and D. moriwakii is further strengthened by the fact that these are the two species in the D. robusta group that are cytologically closest to D. nigromelanica of the related D. melanica group. Of the four derived species, D. sordidula was found to be the closest to the ancestral species. The phylogeny based on the analysis of the gene sequences in the homologous chromosomes agreed with that indicated by the metaphase chromosomes. Since all attempts to obtain hybrids were unsuccessful except for the cross involving D. moriwakii females and D. colorata males, photographic maps of the salivary chromosomes were used to determine homology between the chromosomes of the different species. Evidence is presented to indicate that the D. robusta group originated in Asia (Japan), and that there were two migrations to the New World, the first leading to D. robusta, and the second to D. colorata. It is suggested that the route of migrations was across the Bering Land Bridge, and further, that the migrations occurred during the period from late Oligocene to middle Miocene, 20-25 million years ago.  相似文献   

2.
Two of the three drilled aye-aye incisors collected in 1901 by Grandidier at the subfossil site of Lamboharana were recently rediscovered in uncatalogued collections of the Institut de Paléontologie in Paris. These teeth are not much wider or thicker than those of the extant aye-aye (Daubentonia madagascariensis), but their arc of curvature is noticeably greater. These facts indicate that the teeth probably belong to D. robusta, a large extinct aye-aye whose dentition is otherwise unknown. No other remains referable to Daubentonia have been reported from Lamboharana, although D. robusta is known from other localities in the southwest. The presence of Daubentonia in southern Madagascar does not demonstrate that this region was markedly more humid or densely forested in the recent past. It remains to be established whether the extinction of D. robusta throughout its range in southern Madagascar, and local disappearance of D. madagascariensis everywhere but in the eastern forest biotope, is due to late Holocene climatic change, to anthropogenic effects, or both factors combined.  相似文献   

3.
Deoxyribonucleic acids of members of the family Drosophilidae; e.g., D. melanogaster, D. robusta, D. pellewae, D, immigrans, D. mcclintockae, D. calloptera, C. procnemis and from a tissue culture cells of D. melanogaster have been compared with respect to base composition, heterogenecity, and nucleotide sequence homology. Considerable heterogeneity exists in DNA's from 3rd instar larvae and tissue culture cells. The DNA base composition of adult species ranges from 33-42 moles percent GC; in addition a polydAT component is apparent in larval DNA's. There are about 21 and 29 percent intragenomic homology in DNA's of D. melanogaster and D. immigrans, respectively. Relatively large differences were revealed in the nucleotide sequences of several species by DNA hybridization and thermal stability studies.  相似文献   

4.
Regardless of the well-documented virilis species group, most groups of the Drosophila virilis section have not been completely studied at molecular level since it was suggested. Therefore, phylogenetic relationships among and within species groups of the virilis section are generally unknown. In present paper, the complete mitochondrial ND2 gene and fragment of COI gene in combination with a nuclear gene, Adh coding region, were used to derive the most extensive molecular phylogeny to date for the Drosophila virilis section. A total of 111 individuals covering 61 species were sampled in this study. Novel phylogenetic findings included (1) support for the paraphyly of the melanica and robusta species group and at least two subgroups of the robusta species group, the lacertosa and okadai subgroups, were distinguished as paraphyletic taxa. In addition, (2) present results revealed the sister relationship between D. moriwakii and the robusta subgroup, conflicting with current taxonomy regarding D. moriwakii, which was shifted from the robusta species group to the melanica group. (3) In contrast to the robusta and melanica species groups, monophyly of the polychaeta species group, the angor group and the virilis group was confirmed, respectively. However, the monophyletic quadrisetata species group was resolved with uncertainty. (4) Our analyses of combined data set suggested close relationship between the quadrisetata species group and the unpublished clefta group, and the okadai subgroup is sister to the clade comprising of the quadrisetata and clefta species groups. Within the virilis section, D. fluvialis and three tropical species groups, the polychaeta group, the angor group and the repleta group, are found to branch off earlier than other ingroup taxa. This suggests that the virilis section might have originated in the Old World tropics. Besides, the derived status of the close affinities of the quadrisetata group, the clefta group, and the melanica and robusta groups is probably the result of their adaptation to forests between subtropical and cool-temperate climate. Based on the consideration of the phylogenetic placement of the species of the virilis section, we suggest that at least five independent migrations occurred from the Old World to the New World.  相似文献   

5.
A salivary gland chromosome phylogeny is presented which summarizes the evolutionary relationships of twenty-two species belonging to the sub-genus Drosophila, and members of the twelve species groups: D. melanica, D. repleta, D. carbonaria, D. polychaeta, D. annulimana, D. robusta, D. carsoni, D. virilis, D. funebris and the "picture-wing," D. mimica and D. crassifemur groups (of Hawaii).-Photographic salivary chromosome maps were prepared for all twenty-two species studied. While the chromosomes of different species belonging to the same group can usually be homologized almost completely, so that construction of intragroup phylogenies is easy, chromosomes of members of different groups are so modified structurally that in most cases only short sections can be fully homologized, and these in only one or two chromosome elements.-Broadly homologous chromosome elements were compared for three species at a time, and on the basis of overlapping homologous sections, or overlapping inversions included within homologous sections, the trio of chromosomes, and the species to which they belonged can often be arranged in a two-step phylogenetic series. Detection of many such ordered trios permits construction of a single phylogenetic scheme encompassing all species.-D. nigromelanica, of the D. melanica group is found to be chromosomally intermediate between the rest of its group and the species belonging to other groups, suggesting that it is the most nearly ancestral member of its group. When trios of species including D. nigromelanica and members of two other species groups are compared, it is found that in twelve of fourteen such comparisons the chromosomes of D. nigromelanica are structurally intermediate between those of the members of the other two species groups, indicating the central position of D. nigromelanica in the phylogeny as a whole.-Available cytological evidence indicates that among the nine continental groups studied, it is the D. robusta group which is chromosomally closest to the Hawaiian "picture-wing" groups. Among the members of the Hawaiian groups it is D. primaeva and D. attigua which are found to be closest to the continental species. This finding tends to confirm the earlier conclusion of Carson and Stalker, based on different evidence, that the above two species were in an ancestral position in the Hawaiian phylogeny.-The relationship of the D. robusta and D. melanica groups demonstrated in this paper, the phylogenies within each of these two groups earlier worked out by Narayanan and by Stalker, and the present geographical distributions of the species within them, require that at least three Asiatic-New World migrations must have occurred during the evolution of the two groups.  相似文献   

6.
The ethanolic extract of S. robusta resin (10 and 30 % w/w applied locally in excised and incised wounds) produced a dose-dependent acceleration in wound contraction and increased hydroxyproline content and tensile strength of wounds in rats. The results demonstrate wound healing activity of ethanolic extract of S. robusta resin.  相似文献   

7.
Smith  D.M.  Jackson  N.A.  Roberts  J.M.  Ong  C.K. 《Plant and Soil》1999,211(2):191-205
Limited knowledge of root distributions in agroforestry systems has resulted in assumptions that various tree species are more suited to agroforestry than others, because they are presumed to have few superficial lateral roots. This assumption was tested for Grevillea robusta when grown with maize (Zea mays) in an agroforestry system in a semi-arid region of Kenya. At a site with a shallow soil, root lengths of both species between the soil surface and bedrock were quantified by soil coring, at intervals over four cropping seasons, in plots containing sole stands and mixtures of the trees and crop; the trees were 4–6 years old and they were severely pruned before the third season. Profiles of soil water content were measured using a neutron probe. Prior to pruning of the trees, recharge of soil water below the deepest maize roots did not occur, resulting in significant (P<0.05) suppression of maize root lengths and downward root growth. Maximum root length densities for both species occurred at the top of the soil profile, reaching 1.1–1.7 cm cm-3 for G. robusta, but only 0.5 cm cm-3 for maize grown with trees. Root populations in mixed plots were dominated by G. robusta at all times, all depths and all distances from trees and maize and, thus, there was no spatial separation of the rooting zones of the trees and crop. Competition between G. robusta and maize for soil water stored near the surface was unavoidable, although pruning reduced its impact; complementary use of water by the trees and crop would only have been possible if alternative sources of water were available. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

8.
Two new names are published: Gibasis venustula subsp. robusta D. R. Hunt and Tradescantia poelliaeT). R. Hunt.  相似文献   

9.
利用不同浓度的苦楝树皮和叶、隆缘桉叶和乌桕叶的乙醇提取物对菟丝子及其宿主大豆幼苗进行处理,15d后评价三种提取物对菟丝子和大豆幼苗的影响。结果表明:三种提取物在低浓度时对菟丝子及其宿主大豆幼苗生长发育均无显著影响,在高浓度(0.25g/mL)下,桉树叶提取物对大豆和菟丝子的损伤程度分别达到了64%和70%,苦楝树皮提取物对菟丝子损伤程度为78%,但对大豆幼苗仅为7%。桉树叶和苦楝树皮提取物处理均导致大豆叶片超氧化物歧化酶(SOD)活性升高,最高值分别为相应对照组的2.37倍和2.0倍;但对过氧化物酶(POD)和过氧化氢酶(CAT)活性的影响不同,桉树叶提取物使大豆幼苗POD活性最大值为对照组的2.28倍,而苦楝树皮提取物处理则是CAT活性升高,最大值为对照组的1.58倍,提示桉树叶提取物对大豆较强的伤害作用与其较低的CAT活性有关。  相似文献   

10.
Two new names are published: Gibasis venustula subsp. robusta D. R. Hunt and Tradescantia poelliaeT). R. Hunt.  相似文献   

11.
采用空间代替时间法和典型抽样法,以四川省威远县桉树(Eucalyptus robusta)人工林为研究对象,综合分析其林下植被物种组成及重要值、灌木层和草本层地上、地下和全株生物量以及物种多样性指数(Shannon-Wiener多样性指数H、Simpson优势度指数H′、丰富度指数D和Pielou均匀度指数JSW),探究林下植被的物种多样性和生物量在5个不同林龄(4,5,6,7,8年生)下的动态变化及二者之间的相关性。结果表明:调查到植物共有210种,隶属79科151属,草本层物种数多于灌木层。草本层的五节芒(Miscanthus floridulus)、芒萁(Dicranop?teris pedata)和灌木层的野牡丹(Melastoma malabathricum)、戟叶悬钩子(Rubus hastifolius)在不同林龄下都占据主要优势地位。随着林龄的增大,郁闭度加大,灌木层的D、H和H′值均表现为先增后减的规律;草本层D、H和H′值均呈先增后减再增再减的双峰趋势。草本层各生物量呈先增后减再增的变化趋势;灌木层各生物量呈先增后减的变化趋势。物种多样性与生物量呈显著正相关,草本层的D、H指数是影响生物量的直接因子。桉树人工林林下植被物种分布、组成、物种多样性和生物量对林龄变化的响应不同,表现为不同的动态特征规律,相关结果为我国西南地区桉树林管理提供了数据支撑。  相似文献   

12.
Phenolic constituents from Grevillea robusta   总被引:1,自引:0,他引:1  
Seven phenolic compounds were isolated from a MeOH extract of the leaves of Grevillea robusta. Their structures were determined by various spectral methods including 2D NMR spectroscopy.  相似文献   

13.
银桦次生木质部导管分子观察研究   总被引:17,自引:2,他引:15  
陈树思  唐为萍 《广西植物》2004,24(4):380-382,F006
对银桦 (Grevillearobusta)次生木质部导管分子进行了观察研究。在银桦次生木质部导管分子中存在着许多不同的样式 ,分别对其进行了描述 ,并从导管分子个体发育与系统发育的角度进行了讨论。银桦导管分子中还存在着特殊的样式 ,如具三个单穿孔的导管以及导管分子侧壁上存在明显的皱褶 ,对其也分别进行了讨论  相似文献   

14.
Studies of natural and sexual selection in wild populations of Drosophila have historically provided strong inference for the maintenance of inversion polymorphism. Analysis of geographical variation in the Drosophila robusta chromosomal data collected over more than 50 years from 133 natural populations across eastern North America has confirmed several north–south and east–west clines in the frequencies of some gene arrangements and linked arrangement combinations. Patterns of geographical variation, including several north–south clines, revealed by regression and spatial autocorrelation analyses are concordant with palaeoclimatic shifts, Pleistocene glaciations and historical changes in the composition of North American forest communities. Because D. robusta is a sap-breeder, using the microbe-infested sap exudates of a number of deciduous tree species in which they carry out their life cycle, shifts in climate and palaeovegetation types since the formation of the eastern deciduous forests in the Miocene are hypothesized to be major factors influencing patterns of inversion polymorphisms across the range of this drosophilid species. In areas where sharp deviations in frequencies have been observed, particularly in the mid-western and western portions of the range, these divisions parallel historical geographical disjunctions in the species range that have yet to promote divergence and species formation despite the long history of D. robusta in North America.  © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 81 , 395–411.  相似文献   

15.
《Ibis》1930,72(S1):413-432
With what has already been said of the bird in the Definition of the pair and the Key to species, robusta requires little farther introduction. Some peculiarities in the bird's moults will require particular attention later on, when it comes to defining the racial variation.  相似文献   

16.
Achlya robusta sp. nov. was found on litter (floating twigs, leaves, and roots) in an artificial polluted channel, near a petroleum refinery, in Buenos Aires province, Argentina. The species is described, illustrated and compared with other species of the genus. A. robusta produces mainly smooth and papillate, tuberculate or bullate oogonia and monoclinous antheridial branches. It develops spherical and subglobose oogonia, with the oogonial wall yellowish and containing mainly immature oospheres. The oospores are eccentric and ranging from (1) 4-17 (30) per oogonium.  相似文献   

17.
The clinical features of the 9p-deletion syndrome include dysmorphic facial features (trigonocephaly, midface hypoplasia, upward-slanting palpebral fissures, and a long philtrum) and mental retardation. The majority of these patients appear to have similar cytogenetic breakpoints in 9p22, but some cases show phenotypic heterogeneity. To define the breakpoints of the deleted chromosomes, we studied 24 patients with a deletion of 9p, by high-resolution cytogenetics, FISH with 19 YACs, and PCR using 25 different sequence-tagged sites. Of 10 different breakpoints identified, 9 were localized within an approximately 5-Mb region, in 9p22-p23, that encompasses the interval between D9S1869 (telomeric) and D9S162 (centromeric). Eight unrelated patients had a breakpoint (group 1) in the same interval, between D9S274 (948h1) and D9S285 (767f2), suggesting a chromosome-breakage hotspot. Among 12 patients, seven different breakpoints (groups 3-9) were localized to a 2-Mb genomic region between D9S1709 and D9S162, which identified a breakpoint-cluster region. The critical region for the 9p-deletion syndrome maps to a 4-6-Mb region in 9p22-p23. The results from this study have provided insight into both the heterogeneous nature of the breakage in this deletion syndrome and the resultant phenotype-karyotype correlations.  相似文献   

18.
Satya Prakash 《Genetics》1973,75(2):347-369
The central and marginal populations of D. robusta differ greatly in the level of inversion polymorphism; the marginal populations are monomorphic or nearly so and the central populations are highly polymorphic. This paper presents the frequencies of alleles at forty gene loci in various populations of D. robusta, studied by electrophoresis of proteins and enzymes. Population samples were obtained from eight widely separated populations of D. robusta which included the central, the extreme marginal and the intervening populations between the center and the margins. We find that the proportion of polymorphic loci and average heterozygosity per individual is slightly higher in the marginal populations than the central populations. In D. robusta on an average, 39% of the loci are polymorphic and the average proportion of loci heterozygous per individual is 11%. A breakdown of loci in three categories, viz, hydrolytic enzymes and some other enzymes, larval proteins and glycolytic and Kreb's cycle enzymes, shows that in all populations the level of polymorphism is highest in the hydrolytic enzymes, intermediate in larval proteins and least in the glycolytic and Kreb's cycle enzymes. On the average, the proportion of loci heterozygous per individual for three groups of loci is: hydrolytic enzymes and others (.164), larval proteins (.115) and glycolytic and Kreb's cycle enzymes (.037). We also observe that in all populations the level of polymorphism on the X chromosome is far less than the expected 38%; in salivary gland cells the euchromatic length of the X chromosome is 38% of the entire genome. Lower levels of polymorphism for the X chromosome loci are explained due to low probability of balanced polymorphisms for the X-linked loci since the conditions for establishment of balanced polymorphism for X-linked loci are more restrictive than for the autosomal loci.-The polymorphic loci can be grouped according to pattern of allele frequencies in different populations as follows: (1) The allele frequencies are similar in all populations at the XDH, Pep-1 and Hex-1 loci. (2) The alleles at the Est-1, Est-2, Amy loci and the AP-4(1.0) and the LAP-1(.90) alleles show north south clinal change in frequency. (3) There is north south and east west differentiation at the Pt-5, Pt-8 and Pt-9 loci and the allele AP-4(.81). (4) Polymorphism at loci such as Fum, B.Ox, Hex-8, Pep-2 and Pep-3 are restricted to only one or two of the populations. (5) Allele frequencies at the MDH and ODH loci fluctuate between populations. (6) Allele frequencies at many polymorphic loci such as Est-1, Est-2, LAP-1, AP-4, Pt-5, Pt-8, Pt-9, Pt-16, MDH, Fum change clinally within a gene arrangement. The pattern of gene variation in D. robusta is very complex and cannot be easily explained due to migration of neutral alleles between once-isolated populations or to semi-isolation of neutral alleles. The observations of the pattern of allele variation in different populations, high levels of polymorphism in the marginal populations which have small population size and low levels of polymorphism of the X chromosome loci all support the argument in favor of balancing selection as the main mechanism for the maintenance of these polymorphisms. Environmental factors must play a role in the maintenance of a great deal of these polymorphisms, since we observe clinal allele frequency changes even within a given inversion type.  相似文献   

19.
Morphology and microstructure of the gladius and statolith were studied from 11 specimens of the boreal Pacific giant squid Moroteuthis robusta (mantle length (ML) ranging from 97.5 to 141.5cm) captured on the slope of the north-west Bering Sea in summer and autumn 1993. The most specific feature of the M. robusta gladius is a large and, in cross-section, round rostrum which has been found to be homologous to that of extinct Belemnitida. The functional morphology of the different gladius elements is discussed. Distinct growth increments have been revealed in all three gladius layers in M. robusta. Comparison of peculiarities of microstructure of growth increments, their ways of deposition and their numbers in different gladius layers has shown that all three layers in the M. robusta gladius grow synchronously. M. robusta statoliths are tiny (0.07-0.1% ML) and resemble in shape those of the ommastrephid Illex argentinus. It was impossible to count the total number of growth increments within the statoliths, owing to their complete disappearance in the outer portion of the peripheral zone, and therefore impossible to estimate the age of the M. robusta by using the statolith ageing technique. However, assuming the deposition of growth increments within the gladius as daily, the age of the specimens analysed may vary from 413 to 520 days.  相似文献   

20.
The phylogenetic relationships of several taxa from representative genera, subgenera, groups, and subgroups in the Drosophilidae were examined using sequences from a 905-bp mtDNA fragment. Conventional cloning and sequencing techniques were used to obtain nucleotide sequences. In addition, polymerase chain reaction primers were designed for the rapid amplification and sequencing of this region for the species examined in the Drosophilidae. Phylogenetic analysis was done by cladistic techniques. Because of the coding nature of the 905-bp mtDNA fragment, several separate analyses of these sequences were performed. The genera Scaptomyza and Hirtodrosophila occupy ancestral branching positions in the molecular phylogeny. The genera Chymomyza and Zaprionus have intermediate branching positions, while the subgenera Drosophila and Sophophora are in the most derived position in the molecular phylogeny. Within the subgenus Sophophora, there is little resolution using these sequences, while within the subgenus Drosophila, D. melanica, D. funebris, and D. pinicola form a clade in a derived part of the phylogeny, with D. robusta and D. immigrans branching in an intermediate position in the phylogeny. D. mercatorum, a member of the repleta species group, occupies an ancestral position in the molecular phylogeny.  相似文献   

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