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1.
Two repeated DNA sequences isolated from a partial genomic DNA library of Helianthus annuus, p HaS13 and p HaS211, were shown to represent portions of the int gene of a Ty3 /gypsy retroelement and of the RNase-Hgene of a Ty1 /copia retroelement, respectively. Southern blotting patterns obtained by hybridizing the two probes to BglII- or DraI-digested genomic DNA from different Helianthus species showed p HaS13 and p HaS211 were parts of dispersed repeats at least 8 and 7 kb in length, respectively, that were conserved in all species studied. Comparable hybridization patterns were obtained in all species with p HaS13. By contrast, the patterns obtained by hybridizing p HaS211 clearly differentiated annual species from perennials. The frequencies of p HaS13- and p HaS211-related sequences in different species were 4.3x10(4)-1.3x10(5) copies and 9.9x10(2)-8.1x10(3) copies per picogram of DNA, respectively. The frequency of p HaS13-related sequences varied widely within annual species, while no significant difference was observed among perennial species. Conversely, the frequency variation of p HaS211-related sequences was as large within annual species as within perennials. Sequences of both families were found to be dispersed along the length of all chromosomes in all species studied. However, Ty3 /gypsy-like sequences were localized preferentially at the centromeric regions, whereas Ty1/ copia-like sequences were less represented or absent around the centromeres and plentiful at the chromosome ends. These findings suggest that the two sequence families played a role in Helianthusgenome evolution and species divergence, evolved independently in the same genomic backgrounds and in annual or perennial species, and acquired different possible functions in the host genomes.  相似文献   

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3.
The aim of this study was to determine if individual ticks among the progeny of a single female Rhipicephalus (Boophilus) microplus tick removed from cattle under natural conditions are the result of mating with one or several males. To this end, simulations were run using an existing dataset of genotypes from 8 microsatellite loci to predict the number of samples required and the best locus. Subsequently, 14–22 progeny from each of 15 engorged female ticks removed from three cows, and the engorged females themselves, were genotyped for the BmM1 locus and the minimum number of potential male parents was determined for each progeny group. Of the 15 progeny groups, 10 must have been sired by more than one male, as indicated by the presence of five unique alleles among the progeny or three unique alleles that could not have been contributed by the female. This finding demonstrates multiple paternity in R. microplus.  相似文献   

4.
The cross compatible wild relatives of crops have furnished valuable genes for crop improvement. Understanding the genetics of these wild species may enhance their further use in breeding. In this study, sequence variation of the nuclear Lhs1 gene was used to investigate the population genetic structure and gene flow of Oryza rufipogon and O. nivara, two wild species most closely related to O. sativa. The two species diverge markedly in life history and mating system, with O. rufipogon being perennial and outcrossing and O. nivara being annual and predominantly inbreeding. Based on sequence data from 105 plants representing 11 wild populations covering the entire geographic range of these wild species, we detected significantly higher nucleotide variation in O. rufipogon than in O. nivara at both the population and species levels. At the population level the diversity in O. rufipogon (Hd = 0.712; θ sil = 0.0017) is 2–3 folds higher than that in O. nivara (Hd = 0.306; θ sil = 0.0005). AMOVA partitioning indicated that genetic differentiation among O. nivara populations (78.2%) was much higher than that among O. rufipogon populations (52.3%). The different level of genetic diversity and contrasting population genetic structure between O. rufipogon and O. nivara might be explained by their distinct life histories and mating systems. Our simulation using IM models demonstrated significant gene flow from O. nivara to O. rufipogon, indicating a directional introgression from the annual and selfing species into the perennial and outcrossing species. The ongoing introgression has played an important role in shaping current patterns of genetic diversity of these two wild species. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

5.
Using AP-PCR, the genome of Kamchatka mykiss (Parasalmo (O.) mykiss) was examined. Polymorphic fragments, implying geographic differences among the samples, were selected, cloned, and sequenced. Based on these sequences, longer, specific SCAR primers were selected and constructed. Using the BLAST software program, the sequences were analyzed for analogy to those from the GenBank database. It seemed likely that all sequences obtained belonged to earlier unexamined repeated sequences, variable in the populations of the species of interest. A total of seven SCAR markers, characterized by population-significant variability of the DNA products in Kamchatka geographic group of rainbow trout were constructed. These markers can be used for further investigation of the species Parasalmo (O.) mykiss. The SCAR marker sequences were deposited in GenBank under the accession numbers EU805500 to EU805506.  相似文献   

6.
A genetic transformation system has been developed for callus cells of Crataegus aronia using Agrobacterium tumefaciens. Callus culture was established from internodal stem segments incubated on Murashige and Skoog (MS) medium supplemented with 5 mg l−1 Indole-3-butyric acid (IBA) and 0.5 mg l−1 6-benzyladenine (BA). In order to optimize the callus culture system with respect to callus growth and coloration, different types and concentrations of plant growth regulators were tested. Results indicated that the best average fresh weight of red colored callus was obtained on MS medium supplemented with 2 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.5 mg l−1 kinetin (Kin) (callus maintenance medium). Callus cells were co-cultivated with Agrobacterium harboring the binary plasmid pCAMBIA1302 carrying the mgfp5 and hygromycin phosphotransferase (hptII) genes conferring green fluorescent protein (GFP) activity and hygromycin resistance, respectively. Putative transgenic calli were obtained 4 weeks after incubation of the co-cultivated explants onto maintenance medium supplemented with 50 mg l−1 hygromycin. Molecular analysis confirmed the integration of the transgenes in transformed callus. To our knowledge, this is the first time to report an Agrobacterium-mediated transformation system in Crataegus aronia.  相似文献   

7.
A revision of Penstemon sect. Saccanthera subsect. Serrulati includes a new species (P. salmonensis), a new variety (P. triphyllus var. infernalis), and the elevation of a subspecies to species (P. curtiflorus), bringing the total number of species to eight, which are keyed and described, complete with nomenclature and type citations.  相似文献   

8.
Studying Pneumocystis has proven to be a challenge from the perspective of propagating a significant amount of the pathogen in a facile manner. The study of several fungal pathogens has been aided by the use of invertebrate model hosts. Our efforts to infect the invertebrate larvae Galleria mellonella with Pneumocystis proved futile since P. murina neither caused disease nor was able to proliferate within G. mellonella. It did, however, show that the pathogen could be rapidly cleared from the host.  相似文献   

9.
We studied group formation and anemone use in captively reared anemonefish Amphiprion frenatus. Four small fish (23–32 mm total length) were simultaneously released into a central area of the aquaria (ca. 160 l) that was divided in half with an anemone placed on each half, with the opportunity to settle on either side. Four-day trials were conducted for analyzing settlement patterns. Because of the monogamous mating system, we predicted that small fish should settle in pairs. However, all four small fish settled on the same side in 7 of 14 replicates, which was a higher than expected value under random settlement.  相似文献   

10.
We examined the genetic population structure of Lefua echigonia (Japanese name, hotoke-dojo) using polymerase chain reaction restriction-fragment length polymorphisms (PCR-RFLPs) of the mitochondrial cytochrome b gene and two allozymic loci. The phylogenetic relationships of L. echigonia and those among L. echigonia, Lefua sp. (nagare hotoke-dojo), and L. nikkonis (ezo hotoke-dojo) were also investigated based on the nucleotide sequences of the cytochrome b gene. PCR-RFLP analysis revealed 18 mitotypes in L. echigonia, 2 in Lefua sp., and 1 in L. nikkonis. Phylogenetic trees based on the cytochrome b sequences indicated that the 18 mitotypes in L. echigonia were divided into five distinct groups (South-Kanto, North-Kanto, Tohoku, Echigo, and Tokai-Kinki clades) that differed by 8.5–15.3%, reflecting region-specific geographic distributions. The distributions of alleles in two allozymic loci roughly corresponded to those of the mitotype groups. The divergence times of the five groups were estimated to be about 3.4–7.7 million years ago by applying a general rate for mitochondrial DNA, suggesting that the divergence among them might have occurred in the late Tertiary. It can be inferred that the regional differentiation of each group was mainly due to geographic isolation and that this has been maintained, because the boundaries among the groups corresponded to geological features. The trees also supported the existence of three taxa, L. echigonia, Lefua sp., and L. nikkonis. We concluded that Lefua sp. was distinguished from other species in Lefua by morphological and ecological characters and also by genetic divergences of the cytochrome b gene. Our study also demonstrated the superior efficacy and simplicity of PCR-RFLP analysis as a method for detecting genetic variation in L. echigonia.  相似文献   

11.
The Hox gene Sex combs reduced (Scr) is responsible for the differentiation of the labial and prothoracic segments in Drosophila. Scr is expressed in several specific tissues throughout embryonic development, following a complex path that must be coordinated by an equally complex regulatory region. Although some cis-regulatory modules (CRMs) have been identified in the Scr regulatory region (~75 kb), there has been no detailed and systematic study of the distinct regulatory elements present within this region. In this study, the Scr regulatory region was revisited with the aim of filling this gap. We focused on the identification of Initiator elements (IEs) that bind segmentation factors, Polycomb response elements (PREs) that are recognized by the Polycomb and Trithorax complexes, as well as insulators and tethering elements. To this end, we summarized all currently available information, mainly obtained from high throughput ChIP data projects. In addition, a bioinformatic analysis based on the evolutionary conservation of regulatory sequences using the software MOTEVO was performed to identify IE and PRE candidates in the Scr region. The results obtained by this combined strategy are largely consistent with the CRMs previously identified in the Scr region and help to: (i) delimit them more accurately, (ii) subdivide two of them into different independent elements, (iii) identify a new CRM, (iv) identify the composition of their binding sites and (v) better define some of their characteristics. These positive results indicate that an approach that integrates functional and bioinformatic data might be useful to characterize other regulatory regions.  相似文献   

12.
Expressed sequence tag-derived microsatellite markers (EST-SSR) were generated and characterized in Laminaria japonica using data mining from updated public EST databases and polymorphism testing. Fifty-eight of 578 ESTs (10.0%) containing various repeat motifs were used to design polymerase chain reaction (PCR) amplification primers. A total of 12 pairs of primer were generated and used in the PCR amplification. Alleles per locus ranged from two to ten (average of 5.7). The observed heterozygosities and expected heterozygosities were from 0.045 to 0.543 and from 0.056 to 0.814, respectively. All loci were in Hardy–Weinberg equilibrium and no linkage disequilibrium was detected. These robust, informative, and potentially transferable polymorphic markers appear suitable for population, genetic, parentage, and mapping studies of L. japonica.  相似文献   

13.
The maT clade of transposons is a group of transposable elements intermediate in sequence and predicted protein structure to mariner and Tc transposons, with a distribution thus far limited to a few invertebrate species. We present evidence, based on searches of publicly available databases, that the nematode Caenorhabditis briggsae has several maT-like transposons, which we have designated as CbmaT elements, dispersed throughout its genome. We also describe two additional transposon sequences that probably share their evolutionary history with the CbmaT transposons. One resembles a fold back variant of a CbmaT element, with long (380-bp) inverted terminal repeats (ITRs) that show a high degree (71%) of identity to CbmaT1. The other, which shares only the 26-bp ITR sequences with one of the CbmaT variants, is present in eight nearly identical copies, but does not have a transposase gene and may therefore be cross mobilised by a CbmaT transposase. Using PCR-based mobility assays, we show that CbmaT1 transposons are capable of excising from the C. briggsae genome. CbmaT1 excised approximately 500 times less frequently than Tcb1 in the reference strain AF16, but both CbmaT1 and Tcb1 excised at extremely high frequencies in the HK105 strain. The HK105 strain also exhibited a high frequency of spontaneous induction of unc-22 mutants, suggesting that it may be a mutator strain of C. briggsae.  相似文献   

14.
Genome predictions based on selected genes would be a very welcome approach for taxonomic studies. We analyzed three genes, recN, flaA, and ftsY, for determining if these genes are useful tools for systematic analyses in the genus Anoxybacillus. The genes encoding a DNA repair and genetic recombination protein (recN), the flagellin protein (flaA), and GTPase signal docking protein (ftsY) were sequenced for ten Anoxybacillus species. The sequence comparisons revealed that recN sequence similarities range between 61% and 99% in the genus Anoxybacillus. Comparisons to other bacterial recN genes indicated that levels of similarity did not differ from the levels within genus Anoxybacillus. These data showed that recN is not a useful marker for the genus Anoxybacillus. A 550–600-bp region of the flagellin gene was amplified for all Anoxybacillus strains except for Anoxybacillus contaminans. The sequence similarity of flaA gene varies between 61% and 76%. Comparisons to other bacterial flagellin genes obtained from GenBank (Bacillus, Pectinatus, Proteus, and Vibrio) indicated that the levels of similarity were lower (3–42%). Based on these data, we concluded that the variability in this single gene makes it a particularly useful marker. Another housekeeping gene ftsY suggested to reflect the G+C (mol/mol) content of whole genome was analyzed for Anoxybacillus strains. A mean difference of 1.4% was observed between the G+C content of the gene ftsY and the G+C content of the whole genome. These results showed that the gene ftsY can be used to represent whole G+C content of the Anoxybacillus species.  相似文献   

15.
D. Xie  Y. Hong 《Plant cell reports》2002,20(10):917-922
A protocol was developed for Agrobacterium-mediated genetic transformation of Acacia mangium using rejuvenated shoots as the explant. Axillary buds and shoot apices of adult trees were rejuvenated by culturing them on Murashige and Skoog (MS) medium, and stem segments of rejuvenated shoots were co-cultured with Agrobacterium tumefaciens strain LBA4404 harbouring binary vector pBI121. The selection for transgenic shoots was performed through five consecutive steps on MS medium supplemented with 1.0 mg/l thidiazuron, 0.25 mg/l indole-3-acetic acid and different concentrations of geneticin (G418; 12–30 mg/l) and timentin (T; 50–300 mg/l) in the following order: 12 mg/l G418 and 300 mg/l T for 30 days, 20 mg/l G418 and 200 mg/l T for 60 days, 30 mg/l G418 and 100 mg/l T for 30 days, 12 mg/l G418 and 50 mg/l T for 30 days, and finally 15 mg/l G418 and 5 mg/l gibberellic acid (GA3) for 60 days. Thirty-four percent of the stem segments produced resistant multiple adventitious shoot buds, of which 30% expressed the β-glucuronidase gene. The shoot buds were subjected to repeated selection on MS medium supplemented with 2.0 mg/l 6-benzylaminopurine, 2.5 mg/l GA3 and 20 mg/l G418. Transgenic plants were obtained after rooting on half-strength MS medium supplemented with 2.0 mg/l α-naphthaleneacetic acid, 0.1 mg/l kinetin and 20 mg/l G418. Genomic Southern blot hybridization confirmed the incorporation of the NPTII gene into the host genome.  相似文献   

16.
To evaluate the KRAS, BRAF, EGFR, and HER2 gene status in colorectal cancer by novel techniques and evaluate whether anti-HER2 therapies could be offered in the treatment of these patients. There are conflicting data on the prevalence of BRAF mutations and EGFR and HER2 gene amplification in colorectal KRAS wild type patients. In our study we tried to evaluate these expressions and their relationship to future treatment assays. Clinical–pathological data and paraffin-embedded specimens were collected from 186 patients who underwent colorectal resections at General Yagüe Hospital in Burgos, Spain. KRAS and BRAF status was analyzed by real-time PCR in all patients. EGFR and HER2/NEU gene amplification was detected using fluorescent in situ hybridisation technique (FISH) in 38 KRAS and BRAF wild type patients. KRAS mutations were present in 48% of the colorectal cancer patients. BRAF mutations were present in 6.25% of the KRAS wild type patients. EGFR and HER2 gene amplification was observed in 5.3% and 26.3%, respectively, of KRAS and BRAF wild type colorectal cancer patients. HER2, but not EGFR gene amplification, was frequently observed in KRAS and BRAF wild type colorectal cancer patients. These data indicate that HER2 amplification could be one of the genes to be considered in the therapeutic management of colorectal cancer.  相似文献   

17.
A reproducible plant regeneration and an Agrobacterium tumefaciens-mediated genetic transformation protocol were developed for Perilla frutescens (perilla). The largest number of adventitious shoots were induced directly without an intervening callus phase from hypocotyl explants on MS medium supplemented with 3.0 mg/l 6-benzylaminopurine (BA). The effects of preculture and extent of cocultivation were examined by assaying -glucuronidase (GUS) activity in explants infected with A. tumefaciens strain EHA105 harboring the plasmid pIG121-Hm. The highest number of GUS-positive explants were obtained from hypocotyl explants cocultured for 3 days with Agrobacterium without precultivation. Transgenic perilla plants were regenerated and selected on MS basal medium supplemented with 3.0 mg/l BA, 125 mg/l kanamycin, and 500 mg/l carbenicillin. The transformants were confirmed by PCR of the neomycin phosphotransferase II gene and genomic Southern hybridization analysis of the hygromycin phosphotransferase gene. The frequency of transformation from hypocotyls was about 1.4%, and the transformants showed normal growth and sexual compatibility by producing progenies.  相似文献   

18.
Mitochondria play essential roles in development and disease. The characterisation of mitochondrial proteins is therefore of particular importance. The slowmo (slmo) gene of Drosophila melanogaster has been shown to encode a novel type of mitochondrial protein, and is essential in the developing central nervous system. The Slmo protein contains a conserved PRELI/MSF1p domain, found in proteins from a wide variety of eukaryotic organisms. However, the function of the proteins of this family is currently unknown. In this study, the evolutionary relationships between members of the PRELI/MSF1p family are described, and we present the first analysis of two novel Drosophila genes predicted to encode proteins of this type. The first of these, preli-like (prel), is expressed ubiquitously during embryonic development, whilst the second, real-time (retm), is expressed dynamically in the developing gut and central nervous system. retm encodes a member of a novel conserved subclass of larger PRELI/MSF1p domain proteins, which also contain the CRAL-TRIO motif thought to mediate the transport of small hydrophobic ligands. Here we provide evidence that, like Slmo, both the Prel and Retm proteins are localised to the mitochondria, indicating that the function of the PRELI/MSF1p domain is specific to this organelle.Edited by P. Simpson  相似文献   

19.
20.
Seol E  Jung Y  Lee J  Cho C  Kim T  Rhee Y  Lee S 《Plant cell reports》2008,27(7):1197-1206
Notocactus scopa cv. Soonjung was subjected to in planta Agrobacterium tumefaciens-mediated transformation with vacuum infiltration, pin-pricking, and a combination of the two methods. The pin-pricking combined with vacuum infiltration (20-30 cmHg for 15 min) resulted in a transformation efficiency of 67-100%, and the expression of the uidA and nptII genes was detected in transformed cactus. The established in planta transformation technique generated a transgenic cactus with higher transformation efficiency, shortened selection process, and stable gene expression via asexual reproduction. All of the results showed that the in planta transformation method utilized in the current study provided an efficient and time-saving procedure for the delivery of genes into the cactus genome, and that this technique can be applied to other asexually reproducing succulent plant species.  相似文献   

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