Ploidies

Ploidies
  • 文章类型: Journal Article
    无性生物通常在地理分布上与性亲属不同。这种现象,称为地理孤雌生殖,早就知道了,但是其多样化模式背后的潜在因素一直存在争议。特别有问题的是大多数分类群的无性和多倍体之间的关联。这里,我们在四倍体水平上提出了一个新的地理孤雌生殖系统,对这个复杂的话题有新的见解。我们使用流式细胞仪种子筛选和微卫星基因分型来表征Rubusser中有性和无融合生殖的分布模式以及基因型分布。Glandulosi在其范围内。使用生态模型以及局部尺度的植被和土壤分析来测试生殖组之间的生态位差异。仅在欧洲西北部发现了Apomicts,欧洲和西亚其他地区的性别,一条尖锐的边界横跨中欧。尽管如此,我们发现生态位没有显着差异。基因型丰富度分布表明生殖群体的独立性和二次接触。我们认为,除非生态位分化(由多倍体和/或杂交产生)进化,植物地理孤雌生殖模式背后的主要因素是系统地理历史和中性的微观进化过程,如克隆营业额。
    Asexual organisms often differ in their geographic distributions from their sexual relatives. This phenomenon, termed geographic parthenogenesis, has long been known, but the underlying factors behind its diverse patterns have been under dispute. Particularly problematic is an association between asexuality and polyploidy in most taxa. Here, we present a new system of geographic parthenogenesis on the tetraploid level, promising new insights into this complex topic. We used flow cytometric seed screen and microsatellite genotyping to characterise the patterns of distribution of sexuals and apomicts and genotypic distributions in Rubus ser. Glandulosi across its range. Ecological modelling and local-scale vegetation and soil analyses were used to test for niche differentiation between the reproductive groups. Apomicts were detected only in North-western Europe, sexuals in the rest of the range in Europe and West Asia, with a sharp borderline stretched across Central Europe. Despite that, we found no significant differences in ecological niches. Genotypic richness distributions suggested independence of the reproductive groups and a secondary contact. We argue that unless a niche differentiation (resulting from polyploidy and/or hybridity) evolves, the main factors behind the patterns of geographic parthenogenesis in plants are phylogeographic history and neutral microevolutionary processes, such as clonal turnover.
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  • 文章类型: Journal Article
    The use of antimitotic agents such as colchicine has been common to obtain polyploid organisms. However, this approach entails certain problems, from its toxicity to the operators for being carcinogenic compounds to the instability of the individuals obtained, and the consequent reversion to its original ploidy because the individuals obtained in most cases are chimeric. In vitro culture allows taking advantage of the full potential offered by the cellular totipotence of plant organisms. Based on this, we present a new in vitro culture protocol to obtain polyploid organisms using zeatin riboside (ZR) and eggplant as a model organism. Flow cytometry is used to identify tetraploid regenerants. The regeneration of whole plants from the appropriate tissues using ZR allowed developing polyploid individuals in eggplant, a crop that tends to be recalcitrant to in vitro organogenesis. Thanks to the use of the polysomatic pattern of the explants, we have been able to develop a methodology that allows to obtain stable non-chimeric polyploid individuals from organogenic processes.
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  • 文章类型: Case Reports
    This study searched a rare and aggressive type of cancer in dogs and humans, the breast carcinosarcoma. Both clinical and pathological traits of mammary carcinosarcomas in dogs are similar to humans, such as infrequent occurrence, fast tumor growth, and unfavorable prognosis when compared to carcinomas. Other possible alterations include chromosomal abnormalities that can be useful for the identification of tumoral cells and diagnosis. The aim of this study was to compare the chromosomal features of peripheral lymphocytes and tumor cells in a mammary carcinosarcoma of a 14-year-old female Poodle. Chromosomes were analyzed from 210 metaphases by conventional Giemsa staining, C-banding, and base-specific fluorochrome staining with chromomycin A3 (CMA3+) and DAPI. Of the 105 blood cells, 56.3% followed the standard karyotype of dogs (2n = 78). In contrast, the carcinosarcoma cells showed high chromosomal numbers (104 to 153), divided into 80% hypertriploid (118 to 136 chromosomes), 10.5% hypotetraploid (137 to 153 chromosomes), 5.7% hypotriploid (104 to 116 chromosomes), and 3.8% triploid cells (117 chromosomes). Among the aneuploid cells identified, we highlighted the trisomy of pair 1 and X chromosome once these elements were easily recognized in karyotype because of their size (pair 1) or differential morphology. Heterochromatin in normal cells was restricted to the pericentromeric region of all chromosomes while few C-bands were observed in tumor cells. This apparent loss of heterochromatin in neoplastic cells was supposed to favor centric fusion among formerly acrocentric chromosomes. Fluorochrome staining reinforced this hypothesis once GC-rich segments (CMA3+) were identified on 10 chromosomes from normal cells (2n = 78) whereas carcinosarcoma metaphases had up to 11 chromosomes bearing CMA3 signals in spite of their remarkable high chromosomal numbers. We concluded that, like in humans, the carcinosarcoma in dogs caused genome instability that eventually led to structural and numerical chromosomal aberrations. Besides, this study reinforced the importance of cytogenetic studies in dogs as a reference material for human cancer studies, especially in rare cases, since it is possible to increase knowledge about the characteristics of breast neoplasms in which there is a little availability of similar cases for comparative studies.
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  • 文章类型: Journal Article
    为了对分类单元进行全面的种质评估,减数分裂研究和染色体数据是必不可少的。在目前的努力中,减数分裂研究是在从克什米尔喜马拉雅的自然栖息地收集的26种唇形科的48个种群中进行的,这是喜马拉雅西北部的重要组成部分。五个物种的染色体计数。Dracocephalumnutans(2n=10),金丝雀(2n=22),马鲁比(2n=54),Nepetanervosa(2n=18)和Salviasclarea(2n=22)是印度首次报道的。此外,首次从研究区域-克什米尔喜马拉雅对17种物种进行了细胞学评估。在马鲁比,首次报道了六倍体细胞型(2n=6×=54)。此外,在Calaminthavulgaris(2n=20,40)中观察到二倍体和四倍体细胞形态变异体,纤毛(2n=16,32)和长叶薄荷(2n=20,40)。各种减数分裂异常,如染色质粘性,细胞移植,非同步放电,落后者,染色质桥,等。在某些物种中首次记录了导致花粉异常的情况。介绍了每个属的染色体数数据的全球状况。
    Meiotic studies and chromosome data are imperative in order to have an overall germplasm evaluation of a taxon. In the present effort, the meiotic study is carried out in 48 populations belonging to 26 species of Lamiaceae collected from their natural habitats in Kashmir Himalaya, which forms an important part of Northwest Himalaya. Chromosome counts in the five species viz. Dracocephalum nutans (2n = 10), Lycopus europaeus (2n = 22), Marrubium vulgare (2n = 54), Nepeta nervosa (2n = 18) and Salvia sclarea (2n = 22) are first time reported from India. Besides, 17 species are cytologically evaluated for the first time from the study area-Kashmir Himalaya. In Marrubium vulgare, hexaploid cytotype (2n = 6 × =54) is reported for the first time. Also, diploid and tetraploid cytomorphovariants are observed in Calamintha vulgaris (2n = 20, 40), Elsholtzia ciliata (2n = 16, 32) and Mentha longifolia (2n = 20, 40). Various meiotic abnormalities like chromatin stickiness, cytomixis, nonsynchronous disjunction, laggards, chromatin bridges, etc. leading to pollen abnormalities have been documented for the first time in some species. The worldwide status of chromosome number data in each genus is presented.
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  • 文章类型: Case Reports
    Gonadoblastomas are unusual neoplasias that frequently appear in the dysgenetic gonads of women with chromosome Y anomaly. We present two cases of gonadoblastoma associated with complete gonadal dysgenesis and Turner syndrome, respectively, with dysgerminoma overgrowth found in one case. We were interested in the DNA ploidy, the presence of Y chromosome DNA sequence and the status of chromosome 12p arm among the tumor cells. We performed cytophotometry to analyze the DNA content and fluorescence in situ hybridization (FISH) to identify the Y chromosome and the isochromosome 12p within the tumor cells. The cytophotometric result showed diploid DNA content in gonadoblastoma, whereas dysgerminoma revealed aneuploid DNA. The FISH result revealed Y chromosome DNA sequence within gonadoblastoma and dysgerminoma. Isochromosome 12p was identified in dysgerminoma, but not in gonadoblastoma. We conclude that gonadoblastoma and dysgerminoma have a strong association with the Y chromosome, and dysgerminoma overgrowth is due to further chromosomal aberrations, such as isochromosome 12p. Histological, immunohistocheimcal and molecular studies should render the correct diagnosis. Identifying dysgerminoma overgrowth is crucial since it is associated with adverse prognosis and requires additional therapy.
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  • 文章类型: Journal Article
    BACKGROUND: Hybridisation is presumed to be an important mechanism in plant speciation and a creative evolutionary force often accompanied by polyploidisation and in some cases by apomixis. The Potentilla collina group constitutes a particularly suitable model system to study these phenomena as it is morphologically extensively variable, exclusively polyploid and expresses apomixis. In the present study, the alpine taxon Potentilla alpicola has been chosen in order to study its presumed hybrid origin, identify underlying evolutionary processes and infer the discreteness or taxonomic value of hybrid forms.
    RESULTS: Combined analysis of AFLP, cpDNA sequences and ploidy level variation revealed a hybrid origin of the P. alpicola populations from South Tyrol (Italy) resulting from crosses between P. pusilla and two cytotypes of P. argentea. Hybrids were locally sympatric with at least one of the parental forms. Three lineages of different evolutionary origin comprising two ploidy levels were identified within P. alpicola. The lineages differed in parentage and the complexity of the evolutionary process. A geographically wide-spread lineage thus contrasted with locally distributed lineages of different origins. Populations of P. collina studied in addition, have been regarded rather as recent derivatives of the hexaploid P. argentea. The observation of clones within both P. alpicola and P. collina suggested a possible apomictic mode of reproduction.
    CONCLUSIONS: Different hybridisation scenarios taking place on geographically small scales resulted in viable progeny presumably stabilised by apomixis. The case study of P. alpicola supports that these processes played a significant role in the creation of polymorphism in the genus Potentilla. However, multiple origin of hybrids and backcrossing are considered to produce a variety of evolutionary spontaneous forms existing aside of reproductively stabilised, established lineages.
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  • 文章类型: Case Reports
    OBJECTIVE: To perform a highly detailed semen analysis in a man whose wife had a partial mole.
    METHODS: Case report.
    METHODS: Gynecology departments of two university hospitals and a laboratory of histology/embryology.
    METHODS: A 32-year-old man whose wife had a partial mole.
    METHODS: Sperm characteristics were examined by light microscopy, morphology was analysed by electron microscopy (TEM), DNA fragmentation was evaluated by TUNEL using fluorescence microscopy, and chromosomal abnormalities were assessed by fluorescence in situ hybridization using probes for chromosomes 13, 15, 16, 18, 21, 22, X, and Y.
    METHODS: Sperm count, motility, morphology, DNA fragmentation, and incidence of diploidy, tetraploidy, and aneuploidy.
    RESULTS: Sperm concentration was 61 million/mL, with 31% progressive motility and 4% normal morphology. TEM revealed a high incidence of head, neck, and tail abnormalities as well as the presence of phagocytes. DNA fragmentation was within normal limits (11.6%). Aneuploidy levels were low for all chromosomes tested. However, there was a high level of diploidy, with XY, XX, and YY constitution. Tetraploid sperm (XXYY) were also noted.
    CONCLUSIONS: Semen analysis revealed a high incidence of abnormal morphology and increased diploidy. It may be important to perform FISH testing, to verify increased diploidy in sperm, in men whose wives have had partial moles. These couples could be informed of the option to have preimplantation genetic diagnosis as a means to distinguish between diploid and triploid embryos arising from fertilization of a haploid egg by diploid sperm.
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  • 文章类型: Journal Article
    Standard sperm parameters have a limited power for prediction of the chance of natural conception. Recent studies have indicated that the sperm chromatin structure assay (SCSA) DNA fragmentation index (DFI), a measure for the fraction of sperms with DNA damage, is associated with fertility in vivo. The aim of this study was to evaluate the value of this parameter for prediction of infertility. One hundred and twenty-seven men from infertile couples with no known female factor and 137 men with proven fertility were included. Semen analysis was performed as recommended by the WHO. DFI was assessed using SCSA. Logistic binary regression was used to compute the odds ratios (OR) for infertility. As compared with men with a DFI <10%, men with a DFI between 10% and 20% had an increased risk for infertility (OR 2.5, 95% CI: 1.0-6.1). This was also true for men with a DFI >20% (OR 8.4; 95% CI: 3.0-23). In men with normal standard semen parameters (sperm concentration, motility and morphology) the OR for infertility was increased with DFI >20% (OR 5.1, 95% CI: 1.2-23), whereas if one of the standard semen parameters was abnormal, the OR for infertility was increased already at DFI above 10% (OR 16, 95% CI: 4.2-60). We conclude that SCSA DFI adds to the value of semen analysis in prediction of the chance of natural conception.
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  • 文章类型: Case Reports
    BACKGROUND: ADHD is a common, heritable disorder of childhood. Sex chromosome abnormalities are relatively rare conditions that are sometimes associated with behavioral disorders.
    METHODS: The authors present a male child with ADHD and a major de-novo Y chromosome abnormality consisting of deletion of the long arm and duplication of the short arm. It is possible that the Y chromosomal abnormality is causing the ADHD syndrome in this boy.
    CONCLUSIONS: Considering this case and considering that (a) ADHD is more common in boys than in girls, (b) the transmission of some genes associated with ADHD may occur preferentially from fathers rather than from mothers, and (c) ADHD is more common in children with XYY syndrome and Turner\'s syndrome than in other children, the authors propose that the sex chromosomes may contain risk genes for ADHD.
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    文章类型: Case Reports
    In a recurrence of a rare case of biliary papillomatosis, a disease that often becomes malignant, the presence of human papillomavirus (HPV), Cytomegalovirus (CMV) and Epstein-Barr virus (EBV), as well as DNA ploidy and markers of proliferation and invasion, were examined. No such viruses were identified by polymerase chain reactions. Moreover, markers of invasion, such as laminin, and of proliferation, MIB1 and cyclin A, were absent or at normal levels despite progressive superficial growth of the tumour. The tumour was aneuploid, but the p53-p21 tumour growth suppressor system was not mutated. It was concluded that the presented case of tumour relapse, despite an anamnesis of seven years and its expanding but non-invasive growth, did not contain the viruses that were examined for, and had not become malignant.
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