摘要:

AbstractGenetic engineering offers the opportunity to generate plants with useful new traits conferred by genes originating from a variety of organisms. The objectives of this study were to establish methods for investigating persistence of recombinant plant marker DNA after introduction into soil and to collect data from controlled laboratory test systems. As a model system, we studied the stability of DNA encoding recombinant neomycin phosphotransferase II (rNPT‐II), a neomycin/kanamycin resistance marker, used in plant genetic engineering. The recombinant nature of the target (i.e. fusion of nopaline synthase promoter and NPT‐II coding region) allowed us to design a rNPT‐II‐specific PCR primer pair. DNA preparation and quantitative PCR protocols were established. Effects of temperature and moisture, on DNA persistence in soil were determined in two laboratory test systems. In the first system, purified plasmid DNA was added to soil and incubated under controlled conditions. Up to 0.08% of the rNPT‐II target sequences were detectable after 40 days. In the second system, fresh leaf tissue of transgenic tobacco was ground, added to soil, and incubated under controlled conditions. After 120 days, up to 0.14% of leaf tissue‐derived genomic rNPT‐II sequences were detectable. Under most experimental conditions, leaf tissue‐derived and plasmid DNA were initially degraded at a high rate. A small proportion of the added DNA resisted degradation and was detectable for several months. We hypothesize that this DNA may have been adsorbed to soil particles and was protected from compl

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1996.tb00356.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractMicrosatellite analysis was used to examine parentage and spatial distributions of 62 adult bur oaksQuercus macrocarpa, and 100 saplings in a single stand. Using genotypes scored by PCR products at four microsatellite loci, we determined that 94 saplings matched at least one parent in the stand. Saplings often occur as dense clusters of half‐sibs around the presumed maternal parent, and only four adults were seed parents to a large proportion of the saplings sampled. A stump apparently was the seed parent of the largest cluster of half‐sibs, which occupied a sizeable light gap opened up by the death of their maternal tree. Approximately half of the saplings appeared to have grown from seeds that had not been removed after falling from the tree, and half from seeds that were dispersed beyond the crown of their maternal parent. Long‐distance seed dispersal may be more common than has been previously reported. Extremely high levels of long‐distance pollination were indicated, and pollen donors within the stand were generally distributed randomly around maternal trees. More than half of the saplings had paternal parents outside of the stand. This study demonstrates the utility of microsatellite analysis for studying mating systems, seed dispersal and seedling establishment in natural plant popu

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1996.tb00357.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe yellow‐footed rock‐wallabyPetrogale xanthopusis considered to be potentially vulnerable to extinction. This wallaby inhabits naturally disjunct rocky outcrops which could restrict dispersal between populations, but the extent to which that occurs is unknown. Genetic differences between populations were assessed using mitochondrial DNA (control region) sequencing and analysis of variation at four microsatellite loci among three geographically close sites in south‐west Queensland (P. x. celeris) and, for mtDNA only, samples from South Australia (P. x. xanthopus) as well. Populations from South Australia and Queensland had phylogenetically distinct mtDNA, supporting the present classification of these two groups as evolutionarily distinct entities. Within Queensland, populations separated by 70 km of unsuitable habitat differed significantly for mtDNA and at microsatellite loci. Populations separated by 10 km of apparently suitable habitat had statistically homogeneous mtDNA, but a significant difference in allele frequency at one microsatellite locus. Tests for Hardy‐Weinberg equilibrium and micro‐geographical variation at microsatellite loci did not detect any substructuring between two wallaby aggregations within a colony encircling a single rock outcrop. Although the present study was limited by small sample sizes at two of the three Queensland locations examined, the genetic results suggest that dispersal between colonies is limited, consistent with an ecological study of dispersal at one of the sites. Considering both the genetic and ecological data, we suggest that management of yellow‐footed rock‐wallabies should treat each colony as an independent unit and that conservation of the Queensland and South Australian populations as separate entities

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1996.tb00358.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe stability of a genetically modified strain ofFusarium oxysporumused as antagonist against phytopathogenic formae speciales ofF. oxysporumwas evaluated bothin vitroand in microcosm assays. TheEscherichia colihygromycin B phosphotransferase gene (hph), conferring hygromycin B resistance, was introduced by genetic transformation into a recipient strain marked by benomyl resistance and a dark red pigmentation. Hybridization with the complete plasmid suggested that the integration had generally occurred in a multiple‐tandem array at multiple sites. Among nine independent transformants tested, only three of them were mitotically stable after four rounds of vegetative growth with no selective pressure, while six showed various changes in the integration pattern. One transformant had lost the ability to grow in the presence of hygromycin B. In soil microcosms all the transformants maintained the hygromycin B resistant phenotype, but six of them showed rearrangement of transforming DNA. Only one strain (coded T26.40) underwent no obvious rearrangement both afterin vitrogrowth and after recovery from the soil microcosm. The nine transformants were used in three biological control experiments against Fusarium wilt of carnation in comparison to two untransformed reference strains and to the recipient mutant. A high degree of variability in the biocontrol activity was observed throughout the experiments and only transformant T26.40 consistently controlled the incidence of disease. The results are discussed in relation to risk assessment of the release of transgenic antagonistic fung

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1996.tb00359.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractTuatara represent the last surviving member of the order Rhynchocephalia, a group of reptiles the members of which first appeared in the fossil record 200 million years ago. We report the existence of extensive minisatellite DNA variation in island populations of tuatara, as revealed by the use of heterologous DNA probes and compare this variation to that found in other vertebrates. Patterns of minisatellite variation within and among populations of tuatara on the Taranga and Marotere Islands off the coast of New Zealand are detailed. Individuals from West Bay and South Cove on Motumuka Island show higher levels of bandsharing than that recorded between randomly sampled individuals from the same island. We suggest that these populations comprise a proportion of closely related individuals and that populations within islands are genetically structured. Moreover, we identified individuals which have high levels of bandsharing with substantial proportions of the sampled population, suggesting close kinship. A pairwise, inter‐island comparison of individuals from Motumuka, Whatupuke and Mauimua Islands, reveals significant differences in distribution of restriction fragments in minisatellite DNA profile

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1996.tb00360.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractA survey on 148 clones of the aphidRhopalosiphum padifrom 11 widespread localities has been carried out to study the genetic structure of populations of this species as revealed by mitochondrial DNA restriction site and length polymorphisms as well as by restriction site analysis of a maternally inherited plasmid carried by the aphid eubacterial endosymbiontBuchnera aphidicola. Our results support the existence in the area under study of two main aphid maternal lineages strikingly coincidental with the two main reproductive categories displayed by this species. Those aphid clones possessing an incomplete life cycle that lacks the sexual phase (anholocyclic or androcyclic clones) show mitochondrial DNA (mtDNA) haplotype I and plasmid haplotype I, whereas those clones displaying the complete life cycle (holocyclic clones) posses some other distinct mtDNA haplotypes closely related to each other and plasmid haplotype II. While restriction‐site analysis of maternally inherited markers points to a relatively ancient origin of anholocycly/androcycly (between 460 000 and 1 400 000 years) followed by interrupted gene flow with respect to the ancestral holocyclic population, mtDNA size variation also suggests that historical stochastic processes have a different effect on the evolution of both main aphid lineages. Evidence of occasional nuclear gene flow between lineages and its consequences on the correspondence between maternally inherited haplotypes and life cycle are also presented and discusse

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1996.tb00361.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractWe report the methods and results of molecular genetic identification of the species and, in some cases, geographical origins of whale and dolphin products purchased from retail markets and restaurants in Japan and South Korea. As reported previously (Baker&Palumbi 1994), we used the polymerase chain reaction (PCR) and a portable laboratory to amplify, purify and later sequence a portion of the mitochondrial DNA control region from 16 commercial products purchased in Japan. This ‘spot check’ revealed a surprising variety of species for sale, including minke, fin and humpback whales and one or two species of dolphins sold as ‘kujira’ or whale. In the Korean survey, DNA amplifications were conducted by two of us (C.S.B. and F.C.) working with independent equipment and reagents. The two sets of DNA amplifications were returned to our respective laboratories and sequenced independently for cross‐validation. Among the total of 17 species‐specific sequences we found a dolphin, a beaked whale, 13 Northern Hemisphere minke whales (representing at least seven distinct individuals) and two whales which are closely related to the recognized sei and Bryde's whales but could not be identified as either using available type sequences. We suggest that these two specimens represent a currently unrecognized species or subspecies of Bryde's whale, possibly the so‐called ‘small‐form’ reported from the tropical waters of the Indo‐Pacific.We conclude that molecular systematic analyses of DNA sequences have tremendous utility for the identification of whale and dolphin products. However, there are certain constraints on the application of these techniques for monitoring whaling or trade in whale products. First, PCR and DNA sequencing can generate misleading artefacts. These can generally be recognized or eliminated through experimental controls. Second, phylogenetic reconstructions of DNA sequences can be misinterpreted if the database of type sequences is inadequate or the taxonomy of the group is incomplete. This constraint is, at present, a more serious obstacle to molecular monitoring of whaling. Our results highlight uncertainties about the taxonomic status of oceanic populations and morphological forms of two species (or species complexes) targeted by legal and illegal hunting, the minke and Bryde's whales. Despite these uncertainties, it is difficult to reconcile some of the species available in Japanese and Korean commercial markets with recent catch records made available to the International Whaling Commission. It is particularly disturbing that two specimens of an unrecognized species or subspecies of baleen whale were for sale in a restaurant in South Korea in October, 1994, 8 years after the acceptance of an international moratorium

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1996.tb00362.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe endangered Mauna Kea silversword,Argyroxiphium sandwicensessp.sandwicense(Asteraceae), has experienced a severe decline in distribution and abundance because of predation by alien ungulates. The small remnant natural population on the Mauna Kea volcano contains only 46 individuals. By contrast, the Haleakala silversword,A. sandwicensessp.macrocephalum, consists of a large, vigorous population exceeding 60 000 individuals. Molecular genetic variation in the two populations was assessed using random amplified polymorphic DNA (RAPD) loci. Despite its severe crash in size, the Mauna Kea population did not differ significantly from the Haleakala population in the number of detectably polymorphic loci or in heterozygosity. The lack of substantial reduction in genetic variation, at least as measured with RAPD loci, suggests that the Mauna Kea population may not yet have gone through multiple generations at very small size.

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1996.tb00363.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractDNA fingerprinting was used to test for genetic variation within putative clones ofEucalyptus argutifolia, a rare multistemmed (mallee) species endemic to Western Australia. Hybridization of the M13 repeat sequence toHaeIII digested DNA samples was able to discriminate between seedlings from the same maternal plant, demonstrating the capability of this probe in detecting different individuals of this species. Each of the putative clones yielded a unique banding pattern, but no variation was found within clones. These results are consistent with the notion of clonality inE. argutifoliaand reaffirm that populations are likely to contain considerably fewer individuals than originally anticipated.

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1996.tb00364.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractRandom amplified polymorphic DNA (RAPD) has been used to investigate the interrelationships of 20 populations ofGlobodera pallidacollected originally from field soils around the UK. RAPD analysis revealed a high level of relative genomic diversity within BritishG. pallidabut there was no general correlation of genomic similarity with geographic distribution. Two populations of pathotype Pa1 were clearly divergent from the bulk ofG. pallidaand might represent a distinct introduction. Two other populations, from Scotland and Wales, were also dissimilar from each other and from the rest of theG. pallidapopulations.

ISSN:0962-1083    

DOI:10.1111/j.1365-294X.1996.tb00365.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY