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1.
Four new and one unidentified species of Neohaliotrema Yamaguti, 1965 were obtained from the gills of the Indo-Pacific sergeant Abudefduf vaigensis (Quoy & Gaimard) off Pulau Langkawi, Malaysia. The five species, N. malayense n. sp., N. bombini n. sp., N. andamanense n. sp., N. parvum n. sp. and an unidentified Neohaliotrema sp. (similar to N. macracanthum Zhukov, 1976), are described and distinguished based mainly on features of the haptor. Species of this genus are divisible
into two groups, the ‘maomao group’, with two pairs of morphometrically modified ‘marginal’ hooks and a fenestrated haptor,
and the ‘gracile group’, with morphologically similar marginal hooks and an entire haptor. With the exception of N. bombini n. sp., the species described fit within the ‘maomao group’. It is suggested that the more complex Neohaliotrema species of the ‘maomao group’ have modified hooks 1 and 2 on a haptoral ‘isthmus’ between two large apertures, i.e. ‘windows’,
whereas the less complex species lacking these features are those of the ‘gracile group’. Neohaliotrema spp. have only a single pair of pigmented eye-spots. A fenestrated haptor is unique to the Neohaliotrema spp. of the ‘maomao group’. The generic diagnosis of Neohaliotrema is amended to include new data and a key to its known species is presented. 相似文献
2.
N. Friesen R. Fritsch K. Bachmann 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,95(8):1229-1238
Random amplified polymorphic DNA (RAPD) and genomic in situ hybridization (GISH) methods have been used to verify the hybridogenic
origin and to identify the parental species of some ornamental cultivars in the subgenus Melanocrommyum of the genus Allium. The cultivars had been selected from seed obtained after uncontrolled pollination in breeders’ fields. The combination of
GISH analysis with RAPD markers is very suitable for testing the hybridogenic origin of plants and to ascertain the parental
species of the hybrids in such cases. As suspected, A. macleanii and A. cristophii are the parental species of ‘Globemaster’. The parental species of cultivar ‘Globus’ are A. karataviense and A. stipitatum, and not A. cristophii and A. giganteum as has been assumed on morphological grounds. Cultivars ‘Lucy Ball’ and ‘Gladiator’ are of hybrid origin, though only one
of the parental species, A. hollandicum, could be confirmed. The cultivars ‘Purple Sensation’, ‘Mount Everest’, ‘White Giant’, ‘Michael H. Hoog’ and ‘Mars’ are not
hybrids since neither GISH nor RAPD suggest the presence of a second genome. ‘Purple Sensation’ belongs to A. hollandicum, ‘Mount Everest’, ‘White Giant’ and ‘Mars’ to A. stipitatum,‘Michael H. Hoog’ to A. rosenorum.
Received: 3 July 1997 / Accepted: 9 October 1997 相似文献
3.
Physalia is a genus of pelagic colonial hydrozoans often known by common names such as ‘Portuguese-man-of-war’ or ‘bluebottle’. Siphonophore
systematists generally recognise only a single species in this genus, Physalia physalis, however the name Physalia utriculus is also still in common use, which has led to considerable taxonomic confusion. With some morphological variation between
global regions there is the possibility that this genus holds a substantial amount of cryptic variation. We seek to examine
the genetic structure of Physalia present in New Zealand coastal waters. Fifty-four specimens collected from 13 locations around New Zealand and Australia
were sequenced for both mitochondrial cytochrome c oxidase I (COI) and the first internal transcribed spacer (ITS1) of the nuclear ribosomal cistron. Sequences were analysed
using maximum likelihood and split decomposition neighbour networks to determine conflict between clans (the unrooted analog
of clades). Three clans were identified from both the COI and ITS sequences. The results are complex and clans are not consistent
between the two genes. Nevertheless, it seems that there is substantial cryptic diversity amongst Physalia present in New Zealand coastal waters. 相似文献
4.
Carreras-Aubets M Repullés-Albelda A Kostadinova A Carrassón M 《Systematic parasitology》2011,79(2):145-159
The status of the trematode Aponurus laguncula Looss, 1907 in the western Mediterranean is re-assessed by means of a comparative morphological study and rDNA sequences
based on newly collected material. A. laguncula (sensu stricto) is redescribed from Trachinus draco L. and a new cryptic species of the ‘A. laguncula complex’, Aponurus mulli n. sp., is described on the basis of abundant material from Mullus barbatus L. (type-host) and M.
surmuletus L. off the Spanish Mediterranean coasts. The new species is differentiated from A. laguncula (sensu stricto) by its: significantly larger, elongate body, with maximum width at the level of the ventral sucker; shorter forebody; distinctly
larger sinus-sac, seminal receptacle and seminal vesicle, with the latter also being more elongate; vesicular pars prostatica;
more anteriorly located vitellarium, which consists of eight globular follicles; and distinctly smaller eggs, which are also
smaller in relation to body size and have both their opercular and anopercular poles rounded. The variability and the allometric
growth of the morphological characters in the new species were studied in detail, resulting in additional distinguishing features.
Sequences of the large subunit rRNA (28S) gene (domains D1–D3) and ITS2 rRNA gene region for the new species have been submitted
to GenBank in order to enhance future studies on species differentiation within the ‘A. laguncula complex’. 相似文献
5.
Cryptic species are common among protists and have long been known in ciliates. The ciliate genus Tetrahymena contains a large group of morphologically indistinguishable species referred to as the ‘T. pyriformis’ complex. These species include those reproductively isolated by mating type as well as asexual species characterized by
the absence of the germinal micronucleus. This paper examines the molecular diversity of the species and describes the biogeography
of ‘T. pyriformis’ species. Most species are globally distributed, though the best studied species, T. thermophila, is confined to North America and gives evidence of population structure in local populations. Selfers and asexual species
are common and arise from sexual species, a possible exploitation of nuclear dimorphism. It is argued that the cryptic species
likely have different ecological roles and that the biodiversity of Tetrahymena in particular, and ciliates in general, is underestimated.
Special Issue: Protist diversity and geographic distribution. Guest editor: W. Foissner. 相似文献
6.
The scaly-sided merganser (Mergus squamatus) is an endangered bird species on the IUCN Red List with the estimated global population of less than 2,500 individuals at
present. In the present study, we studied the complete mitochondrial genome (mtDNA) and the phylogenetic of M. squamatus by PCR amplification and GenBank data. The genome was 16,595 bp in length and contained 37 genes (13 protein coding genes,
two rRNAs, and 22 tRNAs) and a non-coding control region (D-loop). All protein-coding genes of M. squamatus mtDNA start with a typical ATG codon, except ND1, COI, and COII uses GTG as their initial codon. TAA, T- and TAG as the terminate
codon occurred very commonly in the sequence. All tRNA genes can be folded into canonical cloverleaf secondary structure except
for tRNASer (AGY) and tRNALeu (CUN), which lose ‘‘DHU’’ arm. The genome sequences had been deposited in GenBank under accession number HQ833701. Based
on the concatenated nucleotide sequences of mtDNA genes (Cyt b and D-loop), we reconstructed phylogenetic trees and discussed
the phylogenetic relationships among ten Anatidae species. The results are different from the present classification, and
we support Lophodytes cucullatus and Mergullus albellus to be members of the genus Mergus. 相似文献
7.
D. A. Lalli A. G. Abbott T. N. Zhebentyayeva M. L. Badenes V. Damsteegt J. Polák B. Krška J. Salava 《Tree Genetics & Genomes》2008,4(3):481-493
Plum pox virus (sharka; PPV) can cause severe crop loss in economically important Prunus species such as peach, plum, apricot, and cherry. Of these species, certain apricot cultivars (‘Stark Early Orange’, ‘Goldrich’,
‘Harlayne’) display significant levels of resistance to the disease and are the genetic substrate for studies of several xlaboratories
working cooperatively to genetically characterize and mark the resistance locus or loci for marker-assisted breeding. The
goals of the work presented in this communication are the characterization of the genetics of PPV resistance in ‘Stark Early
Orange’ and the development of co-dominant molecular markers for marker-assisted selection (MAS) in PPV resistance breeding.
We present the first genetic linkage map for an apricot backcross population of ‘Stark Early Orange’ and the susceptible cultivar
‘Vestar’ that segregates for resistance to PPV. This map is comprised of 357 loci (330 amplified fragment length polymorphisms
(AFLPs), 26 simple sequence repeats (SSRs), and 1 morphological marker for PPV resistance) assigned to eight linkage groups.
Twenty-two of the mapped SSRs are shared in common with genetic reference map for Prunus (T × E; Joobeur et al. 1998) and anchor our apricot map to the general Prunus map. A PPV resistance locus was mapped in linkage group 1 and four AFLP markers segregating with the PPV resistance trait,
identified through bulk segregant analysis, facilitated the development of SSRs in this region.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Lalli, D.A. and Salava, J. contributed equally to this work. 相似文献
8.
Wireworms, the polyphagous larvae of click beetles belonging to the genus Agriotes (Coleoptera: Elateridae), are severe and widespread agricultural pests affecting numerous crops. A previously unknown intracellular bacterium has been
identified in a diseased Agriotes larva. Microscopic studies revealed the subcellular structures characteristic of Rickettsiella infections. Molecular phylogenetic analysis based on 16S ribosomal RNA and signal recognition particle receptor (FtsY) encoding
sequences demonstrates that the wireworm pathogen belongs to the taxonomic genus Rickettsiella. Therefore, the new pathotype designation ‘R. agriotidis’ is proposed to refer to this organism. Moreover, genetic analysis makes it likely that—on the basis of the currently accepted
organization of the genus Rickettsiella—this new pathotype should be considered a synonym of the nomenclatural type species, Rickettsiella popilliae. 相似文献
9.
Costanzo S Jackson AK Brooks SA 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,123(1):33-41
Rhizoctonia solani is a necrotrophic fungal pathogen that causes disease on many crop-plant species. Anastomosis group 1-IA is the causal agent
of sheath blight of rice (Oryza sativa L.), one of the most important rice diseases worldwide. R. solani AG1-IA produces a necrosis-inducing phytotoxin and rice cultivar’s sensitivity to the toxin correlates with disease susceptibility.
Unlike genetic analyses of sheath blight resistance where resistance loci have been reported as quantitative trait loci, phytotoxin
sensitivity is inherited as a Mendelian trait that permits high-resolution mapping of the sensitivity genes. An F2 mapping population derived from parent cultivars ‘Cypress’ (toxin sensitive) and ‘Jasmine 85’ (toxin insensitive) was used
to map Rsn1, the necrosis-inducing locus. Initial mapping based on 176 F2 progeny and 69 simple sequence repeat (SSR) markers located Rsn1 on the long arm of chromosome 7, with tight linkage to SSR marker RM418. A high-resolution genetic map of the region was
subsequently developed using a total of 1,043 F2 progeny, and Rsn1 was mapped to a 0.7 cM interval flanked by markers NM590 and RM418. Analysis of the corresponding 29 Kb genomic sequences
from reference cultivars ‘Nipponbare’ and ‘93-11’ revealed the presence of four putative genes within the interval. Two are
expressed cytokinin-O-glucosyltransferases, which fit an apoptotic pathway model of toxin activity, and are individually being investigated further
as potential candidates for Rsn1. 相似文献
10.
K. Sorkheh B. Shiran M. Khodambshi V. Rouhi S. Ercisli 《Plant Cell, Tissue and Organ Culture》2011,105(3):395-404
Eight native Iranian almond species from three sections, ‘Euamygdalus’ (Prunus communis; Prunus eleagnifolia and Prunus orientalis); ‘Lycioides’ (Prunus lycioides and Prunus reuteri) and ‘Spartioides’ (Prunus arabica, Prunus glauca and Prunus scoparia) were in vitro screened for drought tolerance using sorbitol and polyethylene glycol (PEG) as an osmoticum. Different levels
of water stress were induced using five concentrations of either sorbitol or polyethylene glycol in Woody Plant Medium (WPM).
Water potential of various media ranged from −0.80 to −2.05 MPa and water stress in culture medium adversely affected plantlet
growth. Wild species from ‘Spartioides’ were less affected than ‘Lycioides’ and ‘Euamygdalus’. At the same level of water
potential, sorbitol had lower adverse effects than PEG; the latter being severe. Prunus × sorbitol and Prunus × PEG interactions were significant. At 0.2 M sorbitol and 0.003 M PEG, ‘Spartioides’ produced significantly more roots with
higher total root length and root volume, as well as root-dry weight than those of ‘Lycioides’ and ‘Euamygdalus.’ It is concluded
that in vitro screening of native Iranian almond species under specific and limited water-stress conditions may provide a
system for effectively differentiating the wild species of almond for their expected root mass production under field conditions. 相似文献