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 31 毫秒
1.
The presence of rat kappa-chain allotype specificities (RI-1a and b) has been studied in 13 subspecies of the seven native Australian species of Rattus. RI-1a reactivity was not detected among these rats. On the other hand, extensive cross-reactivity was seen with RI-1b, some sera cross-reacting totally (R. leucopus cooktownensis), some not at all (R. colletti), and the remainder showing at least two distinct levels of partial cross-reactivity, confirming the existence of multiple specificities for RI-1b. Three subspecies show polymorphism with respect to RI-1b cross-reactivity (R. sordidus, R. colletti, and R. l. leucopus) and in one case (leucopus) breeding studies have indicated that there is allelic inheritance of this trait. The segregation of RI-1b reactivity has been studied in crosses and backcrosses made between species differing in their RI-1b reactivity, and the results are consistent with the existence of codominant alleles at a single locus. The fact that these species differ extensively in their karyotype opens the door to possible chromosomal localization of this and other genetic traits.  相似文献   

2.
The distribution of rat kappa-chain allotype specificities (RI-1a and 1b) was studied amongRattus rattus and a variety of other Asian rodents. No sera other than those ofRattus norvegicus showed the presence of RI-1a (DA type), whereas many cross-reacted with RI-1b (LEW-type). While manyR. rattus showedtotal cross-reactivity with RI-1b, various sera from the generaRattus, Bandicota, andTokudaia showed different levels ofpartial cross-reactivity. These results indicate that (1) anti-RI-1b reagents can detectmultiple specificities on LEW-type kappa chains, and (2) these RI-1b specificities, butnot RI-1a, are widely distributed among murid rodents, in seeming contradiction to amino acid sequence data suggesting that RI-1b is more closely related to ancestral rat kappa chains.  相似文献   

3.
A total of 219 wild caught specimens representing 12 of the currently recognised 13 species and subspecies of Australian Rattus have been karyotyped. No two species possessed karyotypes in common, most species and several subspecies differing markedly in chromosome number. While the diploid number varied from 2n=32 to 2n=50, the fundamental number (FN) varied only from 60 to 62, suggesting that Robertsonian rearrangements have played a major role in karyotypic evolution in the group. — Karyotypically the Australian species of Rattus fall into two groups. — the R. lutreolus group and the R. sordidus group. Of the karyotypic forms encountered in the former group, that of R. lutreolus is probably most ancestral because it is identical to that of many Asian species of Rattus. Other karyotypic forms in the R. lutreolus group can be derived as follows: That of (1) R. tunneyi tunneyi and R. t. culmorum by a single fixed pericentric inversion; (2) R. fuscipes fuscipes, R. f. greyi, R. f. assimilis and R. f. coracius by two fixed fusions; (3) R. leucopus cooktownensis by three fixed fusions; and (4) R. leucopus leucopus by four fixed fusions. Of the R. sordidus group, R. s. villosissimus may possess the most ancestral karyotype with 2n=50 (FN=60), from which R. s. colletti (2n=42; FN=60) is derived by four fusions and R. s. sordidus (2n=32; FN=60) by nine fusions, four of which appear to be homologous with those R. s. colletti. — The karyotypic data are in accord with Taylor and Horner's (1973) suggestions that (1) R. t. tunneyi and R. t. culmorum belong to one species; (2) R. lut. lutreolus and R. lut. velutinus belong to one species; (3) R. leu. leucopus and R. leu. cooktownensis belong to one species and (4) R. f. fuscipes, R. f. greyi, R. f. assimilis and R. f. coracius belong to one species. However, the large karyotypic difference between R. s. sordidus and R. s. colletti and R. s. villosissimus may indicate that these groups belong to different biological species. — Supernumerary or B-chromosomes were found in R. f. assimilis and R. t. tunneyi. A single R. t. culmorum was heterozygous for a centric fusion.  相似文献   

4.
The systematics of the Saguinus oedipus group within the bare-face tamarins remains open to question. Hershkovitz (Living New World Monkeys (Platyrrhini), Vol. 1. Chicago: University of Chicago Press, 1977) places the cotton-top and rufus-naped tamarins as subspecies of Saguinus oedipus (S. o. oedipus and S. o. geoffroyi, respectively). In contrast, several other authors have argued that these two taxa should be considered separate species (S. oedipus and S. geoffroyi). Phylogenetic relationships within the group are also disputed. Resolving these different interpretations has been difficult in part because no study of this group has included an objective measure of expected levels of specific vs. subspecific variation. We used facial measurements from 179 adult crania to address the systematics of this group and included a related species that is known to include multiple subspecies. Our sample included three taxa from the S. oedipus group of the bare-face tamarins (S. oedipus, S. geoffroyi, and S. leucopus) and six subspecies from the related hairy-face tamarin species S. fuscicollis. Comparisons to S. leucopus provided a relative measure of species-level differences. Analyses that included S. fuscicollis provided a measure of subspecific variation. There was no evidence of facial sexual dimorphism in any of these taxa. A variety of multivariate statistical analyses including discriminant function and cluster analysis suggest that S. oedipus and S. geoffroyi differ morphologically at a level consistent with species-level distinctions. The extent of differences between these taxa is large. The differences in their facial morphology was on the order of differences between S. oedipus or S. geoffroyi and S. leucopus rather than the extent of variation among S. fuscicollis subspecies. Furthermore, a comparison of collecting localities revealed that the variation we observed among S. oedipus and S. geoffroyi was not clinal but presented a large morphological discontinuity at the boundary between taxa. Our analyses also suggested that S. leucopus is more similar to S. oedipus than is either to S. geoffroyi. Finally, it may be that there are some distinct species within the S. fuscicollis group. However, this hypothesis, along with other phylogenetic relationships suggested by this study, will require more data and further study. © 1992 Wiley-Liss, Inc.  相似文献   

5.
Summary Three subspecies ofPeromyscus inhabiting the montane, foothill, and coastal plain regions of the Carolinas were trapped in midwinter and the occurrence of spontaneous and ration-induced daily torpor was monitored via biotelemetric determination of body temperature. All tests were undertaken with field-caught mice that were subjected to a minimum of laboratory acclimation (two days). The tendency to enter torpor in the presence of adequate food was highest inP. maniculatus nubiterrae, whose natural montane habitat presents it with the greatest seasonal stress in terms of ambient temperature and food availability. This species exhibited significantly (P<0.05) longer spontaneous torpor bouts than did the two lowland subspecies,P. gossypinus gossypinus andP. leucopus leucopus (Table 1). Restriction of food to one-half thead libitum level increased the frequency, duration, and depth (mean minimum body temperature) of torpor in all three species (Fig. 1).P. maniculatus, however, displayed significantly (P<0.001) longer episodes of torpor induced by rationing than did either of the other two subspecies. The ability to compensate for a reduction in energy intake by adjusting levels of energy utilization may profoundly affect survival during short-term environmental stress in any of these three species.  相似文献   

6.
The cross-reactivity of five different rabbit polyclonal antibodies to human IgG and IgG subclass (IgG1, IgG2, IgG3, and IgG4) was determined by competitive ELISA with nine nonhuman primate species including five apes, three Old World monkeys, and one New World monkey. As similar to those previously reported, the reactivity of anti-human IgG antibody with plasma from different primate species was closely related with phylogenic distance from human. Every anti-human IgG subclass antibody showed low cross-reactivity with plasma from Old World and New World monkeys. The plasma from all apes except for gibbons (Hylobates spp.) showed 60 to 100% of cross-reactivity with anti-human IgG2 and IgG3 antibodies. On the other hand, chimpanzee (Pan troglodytes andPan paniscus) and orangutan (Pongo pygmaeus) plasma showed 100% cross-reactivity with anti-human IgG1 antibody, but gorilla (Gorilla gorilla) and gibbon plasma showed no cross-reactivity. The chimpanzee and gorilla plasma cross-reacted with anti-human IgG4 antibody at different reactivity, 100% in chimpanzee and 50% in gorilla, but no cross-reactivity was observed in orangutan and gibbon plasma. These results suggest the possibilities that the divergence of “human-type” IgG subclasses might occur at the time of divergence ofHomo sapience fromHylobatidae, and that the molecular evolution of IgG1 as well as IgG4 is different from that of IgG2 and IgG3 in great apes, this is probably caused by different in development of immune function in apes during the course of evolution.  相似文献   

7.
Population dynamics and habitat preferences of the dusky rat, Rattus colletti, were examined in the seasonal wetlands of the South Alligator River. Northern Territory, between late 1979 and 1982. Demographically, the species is characterized by short-term seasonal shifts between habitats superimposed on a longer-term irregular pattern of prolonged breeding and population irruption, followed by periods of relative rarity. These patterns are determined by the train of climatic events. The flexible life history strategy and movement patterns of R. colletti reflect fine-scale adaptation to a climatic regimen which is markedly seasonal, but also highly variable between years in the amount and temporal patterning of rainfall. The distribution of R. colletti amongst vegetation types is influenced by two sets of environmental factors, both reflecting a gradient in elevation, soil type and vegetation. The primary factors are vegetative cover and height, and the extent and duration of flooding; the secondary set comprises buffalo-induced features such as the degree of pugging and grazing. These factors are interrelated, and their relative importance to R. colletti varies greatly between seasons. Feral buffalo appear to exacerbate the harsh effects of the wet and dry seasons. The removal of these animals may ameliorate environmental conditions considerably, both temporally and spatially, resulting m generally higher, more stable and spatially less variable populations of R. colletti.  相似文献   

8.
Results of a mark-release study of Rattus sordidus colletti (Gould) on sub-coastal, treeless plains in the monsoonal north of the Northern Territory of Australia are given for 5 years. R. s. colletti is the dominant component of the small mammal fauna of these plains, with only small numbers of Melomys spp. and Planigale maculata also occurring. Two classes of peak densities were observed. Localized peaks resulted from non-breeding adult R. s. colletti refuging onto the marginally higher levees during flooding of the plains, and also from refuging into a lower-lying area at the end of a dry-season drought. Generalized peak densities resulted from peaks in reproductive effort. In 1972 and 1974, reproduction was confined to the period immediately following the monsoons, but in 1973 breeding continued throughout the dry season, following unseasonal rain in June. Thus, generalized peak densities were observed in one year at the beginning of the dry season, and in another at its end. The relatively shallower flooding and mildness of the 1972–3 wet season resulted in commencement of breeding earlier in 1973 than in 1974, while rapid severe flooding of the plains in December 1974 resulted in mass mortality and failure of the refuging populations of adults to recolonize the lower plains in 1975. R. s. colletti remained extremely rare until November 1976, when the study was terminated. The good conditions which allowed reproduction during the dry season of 1973 were reflected in rapid growth rates at that time, compared with rates approaching zero in the 1974 dry season. R. s. colletti is the most fecund form of Australian Rattus species. This high fecundity appears to compensate for the restriction, by dry-season aridity and wet-season flooding, of the breeding season in most years to a short period immediately following the monsoons. In unusual years with rainfall during the dry season, the high fecundity gives R. s. colletti populations the capacity to reach very high densities.  相似文献   

9.
Although several investigations have been made from different viewpoints, the classification or interspecific relationships ofSaguinus still remain uncertain. In the present study, we applied multivariate analysis methods to dental measurements of part ofSaguinus populations of sufficient sample size and obtained the following conclusions.Saguinus can be classified into two main groups: one consists ofS. oedipus andS. leucopus, and the other ofS. fuscicollis, S. nigricollis, S. labiatus, andS. mystax. Concerning the former group, the two subspecies ofS. oedipus, S. o. oedipus, andS. o. geoffroyi, show a close affinity with each other and also a close relationship toS. leucopus, while the latter group consists of two subgroups of species, one includingS. fuscicollis andS. nigricollis, and the other includingS. labiatus andS. mystax. The biological distance betweenS. oedipus oedipus andS. o. geoffroyi is slightly larger than that between the pairs ofS. fuscicollis andS. nigricollis and ofS. labiatus andS. mystax. Factor analysis revealed significant factors which could explain the differences among the seven maleSaguinus populations. Taking all the results into account, it seems necessary to reconsider the phylogenetic relationships within the genusSaguinus.  相似文献   

10.
Genetic variation within the Murina species group, which includes S. murina, S. gilberti, S. leucopus, S. dolichura and S. archeri, was examined through analyses of complete 12S rRNA, partial control region mitochondrial DNA sequences and partial omega-globin nuclear DNA sequences. Sminthopsis butleri was found to be an additional member of the Murina group, and appears to be most closely related to S. leucopus rather than the morphologically similar S. archeri. This latter species appears to be the most divergent member of the group, and there is a possible sister relationship between S. murina and S. gilberti, as suggested by previous allozyme evidence. It appears that the systematic affinities of the taxonomically problematic northeastern Queensland populations of both S. murina and S. leucopus and a disjunct population of S. gilberti (from the Western Australia/South Australia border) are indeed with those respective species; although each appears to belong to a distinct morphological and genetic lineage. A specimen of S. leucopus from Queensland was found to be as divergent from each of the southeastern Australian S. leucopus subspecies as they are from each other, suggesting that this northern population of S. leucopus may also warrant recognition as a distinct taxon. Specimens of S. murina murina were found to be genetically divergent from each other, and this subspecies appears to be paraphyletic, as suggested by previous morphological evidence. * This paper is the second part of a series dealing with the systematics and evolution of the dasyurid marsupial genus Sminthopsis. Part one covered the Macroura species group and was published in 2001 in the Journal of Mammalian Evolution 8, 149–170.  相似文献   

11.
Greater structural complexity of understory vegetation may be one factor that contributes to the negative relation ship between density of generalist rodents (eg,Peromyscus leucopus Rafinesque, 1818) and forest patch area; however, this hypothesis is difficult to test. We removed the problem of multicollinearity among variables by analyzing changes in structural complexity and relative abundance ofP. leucopus in 15 forest patches (1.3–200 ha) over a 3-yr period. We found that an in crease in the relative abundance ofP. leucopus was associated with an increase in structural complexity of understory vegetation in the same patches between years. Structural complexity of the understory was greater in smaller forest patches which we speculate may be influenced by moisture. It is possible that understory vegetation provides greater food availability and/or cover from some predators in small patches, but the specific mechanism(s) remains unclear. Multiple factors can potentially influence populations ofP. leucopus, but our results provide strong evidence that structural complexity of understory vegetation positively in fluences relative abundance ofP. leucopus in fragmented habitats.  相似文献   

12.
Difficulties in delimiting well-defined entities in the dogroses (Rosa sect.Caninae) has resulted in very variable taxonomic treatments. The present study was undertaken to provide a background for taxonomy as well as plant breeding. Morphometric diversity was analysed on seedlings obtained from field collections in South Sweden of three species,Rosa dumalis, R. rubiginosa andR. villosa. A canonical variates analysis showed that the three species are relatively distinct whereas two subspecies ofR. dumalis were less well discriminated. Analyses of variance demonstrated that intraspecific variation is pronounced inR. dumalis and, to a lesser extent, inR. villosa.  相似文献   

13.
Asperula sect.Oppositifoliae is validated. 2 new species ofAsperula and 7 new species and 1 variety ofGalium from Iran are described, discussed in respect to their affinities and illustrated. 2 subspecies are raised to species rank.  相似文献   

14.
K. D. Hill  S.-L Yang 《Brittonia》1999,51(1):48-73
The genusCycas is revised for Thailand. Ten species are enumerated, five of them described as new (C. chamaoensis, C. clivicola, C. litoralis, C. nongnoochiae, C. tansachana), with one new subspecies (C. clivicola subsp.lutea). The species are placed within an infrageneric classification previously outlined. Distributions of the taxa are mapped, eight of the species are illustrated, and a key to species is provided. Previous records ofC. circinalis andC. rumphii from Thailand (here not regarded as indigenous in Thailand) are discussed.  相似文献   

15.
The number of recognized flea‐borne pathogens has increased over the past decade. However, the true number of infections related to all flea‐borne pathogens remains unknown. To better understand the enzootic cycle of flea‐borne pathogens, fleas were sampled from small mammals trapped in central Pennsylvania. A total of 541 small mammals were trapped, with white‐footed mice (Peromyscus leucopus) and southern red‐backed voles (Myodes gapperi) accounting for over 94% of the captures. Only P. leucopus were positive for examined blood‐borne pathogens, with 47 (18.1%) and ten (4.8%) positive for Anaplasma phagocytophilum and Babesia microti, respectively. In addition, 61 fleas were collected from small mammals and tested for pathogens. Orchopeas leucopus was the most common flea and Bartonella vinsonii subspecies arupensis, B. microti, and a Rickettsia felis‐like bacterium were detected in various flea samples. To the best of our knowledge, this is the first report of B. microti DNA detected from a flea and the first report of a R. felis‐like bacterium from rodent fleas in eastern North America. This study provides evidence of emerging pathogens found in fleas, but further investigation is required to resolve the ecology of flea‐borne disease transmission cycles.  相似文献   

16.
Eleven populations of the rosy bitterling,Rhodeus ocellatus, from different localities in Japan, were genetically compared at 16 protein-coding loci using starch-gel electrophoresis. Two loci,Ldh-2 andPgdh, were demonstrated as diagnostic markers for the identification of two subspecies;R. ocellatus kurumeus, which is native to Japan, andR. ocellatus ocellatus, which was introduced from China. The two subspecies were distinguished by the complete substitution of different alleles between them. Population ofR. ocellatus kurumeus occurring in Yao City, Osaka, and in Kanzaki, Saga Prefecture were genetically closely related to each other (genetic distance: D=0.056) but distantly so toR. ocellatus ocellatus from Saitama Prefecture (D=0.202 or 0.265). Electrophoretic analyses also elucidated the existence of hybrid populations of the two subspecies. The populations ofR. ocellatus kurumeus in Yao City had lower genetic variability and a lower incidence of white coloration on the ventral fins than populations of the same in Saga Prefecture. The present study strongly implies that the introduction of the foreign freshwater fishes with subspecific differentiation, into the original range of indigenous subspecies, should be averted not to bring the genetic pollution.  相似文献   

17.
Mate recognition systems (MRSs) are complex signal-receivertraits. The present study addressed the roles of phylogeny,ecology, and geography in shaping the MRS of the African stripedmouse (Rhabdomys), which has a wide distribution in southernAfrica. Two putative species are recognized, which have differentecologies: Rhabdomys pumilio (arid) and Rhabdomys dilectus (mesic).The latter may be further subdivided into 2 subspecies (R. dilectusdilectus and R. dilectus chakae). Using 2 discrete populationsper taxon, we investigated within- and between-taxon variationsin male odor quality and female perception using habituation-discriminationand habituation-generalization tests, and female preferencein 2-way choice tests. Our results indicate: 1) no within-taxonvariation in odor quality, perception, or preference; 2) the2 subspecies of R. dilectus carry signals of different qualitiesbut share a common odor characteristic distinct from that ofR. pumilio; 3) female R. pumilio did not show a preference whentheir own species and R. d. chakae odors were presented simultaneouslybut displayed assortative preference when the alternative wasR. d. dilectus; 4) females of the 2 subspecies showed dissimilarpreferences: R. d. chakae for the genetically more similar taxonand R. d. dilectus for the most different one. Although we couldnot rule out the influence of ecology, we concluded that phylogenyappeared a more parsimonious explanation for the pattern ofdivergence in Rhabdomys. Further, we discuss our results inlight of current models on signal-receiver coevolution.  相似文献   

18.
A cell wall lytic enzyme (gamete wall-autolysin) and a polyclonal antiserum raised against one of the major cell wall glycopeptides ofChlamydomonas reinhardtii were used to study their cross-reactivities with the cell walls of variety of members of the Volvocales. Lytic enzyme was able to digest completely the cell walls of five species ofChlamydomonas (C. reinhardtii group), six species ofGonium and two species ofAstrephomene. The colonial structures ofGonium andAstrephomene were broken into individual cells by exposure to the enzyme and protoplasts were then formed. These organisms also showed a strong cross-reactivity with anti-cell wall glycopeptide by an indirect-immunofluorescence test. The cell walls ofChlamydomonas angulosa, Dysmorphococcus globosus, Pandorina morum, Eudorina elegans, Volvulina steinii, Pleodorina california andVolvox carteri all showed a strong cross-reactivity to the antibody, although they were insensitive to the lytic enzyme. Many other species ofChlamydomonas, Carteria crucifera, Chlorogonium elongatum, Polytoma uvella, Haematococcus lacustris, Lobomonas piriformis, Phacotus lenticularis, Pteromonas angulosa, Stephanosphera pluvialis, andPyrobotrys casinoensis had cell walls which were resistant to the enzyme and showed no or weak cross-reactivity with the antibody. Based on the results, a possible evolutionary sequence from a unicellular relative ofC. reinhardtii to the multicellular algae is discussed.  相似文献   

19.
All study strains ofBacteroides gingivalis, B. asaccharolyticus, andB. melaninogenicus subspecies possessed numerous pilus-like fibers and capsule-like outer surface structures. The capsular morphology varied between the different species and subspecies.B. gingivalis strongly agglutinated 16 erythrocyte species studied.B. asaccharolyticus showed variable and weak agglutination of only a few erythrocyte species.B. melaninogenicus subsp.intermedius strains strongly agglutinated rabbit erythrocytes and exhibited variable, often weak agglutination of 8 other erythrocyte species. Preparations of capsular polysaccharide or lipopolysaccharide fromB. gingivalis failed to agglutinate human erythrocytes, while pili preparations from the same organisms possessed marked hemagglutinating activity.B. gingivalis cells adhered in high numbers to human buccal epithelial cells, whereas strains ofB. asaccharolyticus failed to show measurable adherence. Oral strains ofB. melaninogenicus subsp.intermedius feebly adhered to the buccal epithelial cells. Pretreatment ofB. gingivalis cells with serum or saliva prevented the adherence to epithelial cells. Our findings suggest that cell surfaces with distinct properties exist on the various black-pigmentedBacteroides species and subspecies and this may accout for markedly differing ability of these organisms to attach to mammalian cells.  相似文献   

20.
The rust fungusGymnoconia nitensinfects blackberry (Rubus argutus) systemically in regions of the continental United States, producing bright yellow–orange masses of spores on newly developing floricanes during springtime. In tests to determine the suitability of this rust as a biological control agent forR. penetransin Hawaii, a species now thought to be conspecific withR. argutus,rooted cuttings of the Hawaiian plants were grown at North Carolina State University, inoculated, and observed. Other introduced weedyRubusspp. in Hawaii, includingR. ellipticus, R. rosifolius,andR. glaucus,as well as the two endemic speciesR. hawaiensisandR. macraei,also were inoculated. No species ofRubusare of commercial importance in Hawaii, but the protection of the native species, of whichR. macraeiis rare, was of utmost concern. The native Hawaiian species did not survive well in North Carolina in this study, however. Later availability of a plant pathogen containment laboratory in Hawaii enabled similar tests to be conducted at that facility. In addition to the above species,R. spectabilis(salmonberry), a species native to the Pacific Northwest with which the HawaiianRubusspp. are thought to share a common ancestor, was inoculated in Hawaii. Infection withG. nitensunder natural field conditions becomes apparent only when sporulation occurs on floricanes the second year following infection. However, experimental inoculation led to early responses of chlorotic leaf flecking and puckering, leaf and stem contortion, and stem gall formation, indicating the sensitivity ofR. penetrans(=R. argutus),R. hawaiensis,andR. macraeito this rust. Apparent systemic infection also resulted in sporulation on one plant ofR. macraei.Ability to attack the endemic species suggests thatG. nitenswould not be suitable for release in Hawaii as a biological control agent, at least on the islands with populations of the native 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