Search results for "Ploidy"
showing 10 items of 299 documents
RCS1, a gene involved in controlling cell size inSaccharomyces cerevisiae
1991
Cloning and sequencing of RCS1, Saccharomyces cerevisiae gene whose product seems to be involved in timing the budding event of the cell cycle, is described. A haploid strain in which the 3'-terminal region of the chromosomal copy of the gene has been disrupted produces cells that are, on average, twice the size of cells of the parental strain. The critical size for budding in the mutant is similarly increased, and the disruption mutation is dominant in a diploid heterozygous for the RCS1 gene. Spores from this diploid have a reduced ability to germinate, the effect being more pronounced in the spores carrying the disrupted copy of RCS1. However, disrupted cells recover from alpha-factor tr…
High resolution analysis and differential condensation in RBA-banded human chromosomes.
1981
Human prophase, premetaphase, and mid-metaphase chromosomes are prepared and analyzed using the thymidine cell synchronization technique and R-banding patterns (RBA). Haploid sets with 700–1000 bands can be demonstrated. Sequences of chromosomes of different degrees of condensation are helpful for a better understanding and classification of regions of extended chromosomes. A considerable variation in the condensation of parts of homologous chromosomes is reflected in the variability of the arm ratio. This differential condensation of chromosomes is entirely effected by variation of the degree of condensation in AT rich interbands and can be attributed to the degree of labeling by BrdU.
Using Anther Culture Method for Flax Breeding Intensification
2015
Flax breeding is a long and complicated process based on hybridization and following selection of the best plants. Because of possible occasional cross-pollination the development of genetically stable homozygous lines could last more than 15 years. For more rapid creating of initial material for flax breeding anther culture methods for producing doubled haploid (DH) lines could be used successfully. The goal of this study was to develop the best anther culture protocol for producing DH lines from hybrids included in Latvian flax breeding programme and to do preliminary field evaluation of obtained DH lines. F4 hybrids were used in the experiment. Method, most applicable for establishing of…
Estrogen-Induced Mutations and Its Role in the Development of Tumorigenesis
2006
Using RAPD-PCR fingerprinting, the detection of mutations induced by estrogen (E) exposure was studied in nonmalignant- and malignant cells. Cells exposed to 17α-and 17β-estradiol, diethylstilbestrol, bisphenol A, and α-zearalanol induced mutations in different regions of the genome. They consisted of insertion/deletion as a result of point or length mutations and quantitative changes as a result of hypoploidy or polyploidy. We also detected several mutated loci in tumor-free tissues, adjacent to tumors, and DES-induced tumors. The data suggest that these mutations occurred in early stages of stilbene E-induced renal carcinogenesis, and that they may be induced as a result of stilbene E tre…
Genome size and chromosomes in marine sponges [Suberites domuncula, Geodia cydonium]
1995
The genome size of the marine sponges Suberites domuncula and Geodia cydonium has been determined by flow cytofluorometric analysis using diamidino-phenylindole [DAPI]. Using human lymphocytes as reference the amount of DNA in cells from S. domuncula has been determined to be 3.7 pg and that of G. cydonium 3.3 pg. While no chromosomes could be identified in G. cydonium, the karyotype of the Suberites domuncula is 32 chromosomes in the diploid state. The size of the chromosomes was between 0.25 and 1.0 micron. No pronounced banding pattern was visible.
Value of Deoxyribonucleic Acid Ploidy and Nuclear Morphometry for Prediction of Disease Progression in Renal Cell Carcinoma
1996
AbstractPurpose: A retrospective study was performed on 108 patients with localized renal cell carcinoma (pT1 to 3a N0M0) to determine whether ploidy and nuclear morphometry are independent predictive factors in addition to stage and grade.Materials and Methods: Deoxyribonucleic acid (DNA) content was analyzed by flow cytometry and nuclear morphometry characterized by 5 nuclear descriptors. A Cox proportional hazards regression model was used to identify significant prognostic factors for disease progression.Results: A model combining tumor stage and grade, DNA ploidy and nuclear minor axis was chosen as optimal with risk of disease progression increased with increasing tumor stage and grad…
Allium albanicum (Amaryllidaceae), a new species from Balkans and its relationships with A. meteoricum Heldr. & Hausskn. ex Halácsy
2019
A new species, Alliumalbanicum, is described and illustrated from Albania (Balkan Peninsula). It grows on serpentines or limestone in open rocky stands with a scattered distribution, mainly in mountain locations. Previously, the populations of this geophyte were attributed to A.meteoricum Heldr. & Hausskn. ex Halácsy, described from a few localities of North and Central Greece. These two species indeed show close relationships, chiefly regarding some features of the spathe valves, inflorescence and floral parts. They also share the same diploid chromosome number 2n =16 and similar karyotype, while seed testa micro-sculptures and leaf anatomy reveal remarkable differences. There are …
Taxonomic complexity in the halophyte Limonium vulgare and related taxa (Plumbaginaceae): insights from analysis of morphological, reproductive and k…
2014
Part of a special issue on halophytes and saline adaptations Background and Aims Limonium is awell-known example of a group of plants that is taxonomically complex due to certain biological characteristics that hamper species’ delineation. The closely related polyploid species Limonium vulgare Mill., L. humile Mill. and L. narbonense Mill. are defined species and can be used for studying patterns of morphological and reproductive variation. The first two taxa are usually found in Atlantic Europe and the third in the Mediterranean region, but a numberof intermediate morphological formsmay be present alongside typical examples of these species. This study attempts to elucidate morphological, …
Mapping genomic rearrangements in titi monkeys by chromosome flow sorting and multidirectional in-situ hybridization.
2004
We developed chromosome painting probes for Callicebus pallescens from flow-sorted chromosomes and used multidirectional chromosome painting to investigate the genomic rearrangements in C. cupreus and C. pallescens. Multidirectional painting provides information about chromosomal homologies at the subchromosomal level and rearrangement break points, allowing chromosomes to be used as cladistic markers. Chromosome paints of C. pallescens were hybridized to human metaphases and 43 signals were detected. Then, both human and C. pallescens probes were hybridized to the chromosomes of another titi monkey, C. cupreus. The human chromosome paints detected 45 segments in the haploid karyotype of C.…
Incomplete sequence homogenization in 45S rDNA multigene families: intermixed IGS heterogeneity within the single NOR locus of the polyploid species …
2014
† Background and Aims Ribosomal sequences have become the classical example of the genomic homogenization of nuclear multigene families. Despite theoretical advantages and modelling predictions that support concerted evolution of the 45S rDNA, several reports have found intragenomic polymorphisms. However, the origins and causes of these rDNA polymorphisms are difficult to assess because seed plants show a wide range of 45S rDNA loci number variation, especially in polyploids. Medicago arborea is a tetraploid species that has a single 45S rDNA locus. This feature makes this species a suitable case study to assess the fate of ribosomal IGS homogenization in polyploid species showing nucleolu…