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Environmental Health Perspectives Dec 1993In most investigations of cell proliferation in vivo, the population under study consists of mononuclear diploid cells that undergo replication via normal complete... (Review)
Review
In most investigations of cell proliferation in vivo, the population under study consists of mononuclear diploid cells that undergo replication via normal complete division cycles. Because the phenomena associated with the cell cycle are sequential, only one is normally measured and it is usually adequate to quantify the proliferative activity in one of two ways. The first involves labeling the cells undergoing semi-conservative DNA synthesis with a radioactive DNA precursor, preparing autoradiographs of histological sections, and counting labeled nuclei. The other commonly studied parameter of cell proliferation is mitotic activity. The livers of rats and mice, unlike those of other mammals, consist mainly of hepatocytes that contain two classes of cell with respect to nuclei and several ploidy classes. These classes of hepatocytes arise as the result of modified cell division cycles. The peculiar cytological composition of the rodent liver has, until recently, caused difficulties in the measurement and interpretation of cell ploidy and cell proliferation by the above methods. Flow cytometry and fluorescence-activated cell sorting used in conjunction with quantitative fluorescent stains for DNA and fluorescently labeled antibodies to bromodeoxyuridine have permitted the rapid and precise quantification of cell proliferative activity in the rodent liver. Studies using these techniques have revealed that proliferative activity of hepatocytes may occur in different subpopulations of cells depending on the kind of toxicological injury inflicted on the animal.
Topics: Animals; Cell Cycle; Cell Division; DNA; Genes; Liver; Ploidies; Polyploidy; Rodentia
PubMed: 8013426
DOI: 10.1289/ehp.93101s567 -
Experientia. Supplementum 1987Plant taxa that reproduce asexually display some distinct geographical and ecological patterns. A literature review reveals that such taxa 1) tend to have larger ranges,... (Review)
Review
Plant taxa that reproduce asexually display some distinct geographical and ecological patterns. A literature review reveals that such taxa 1) tend to have larger ranges, 2) tend to range into higher latitudes, and 3) tend to range to higher elevations than do their sexual relatives. Asexual taxa have a greater tendency than sexual taxa do to colonize once-glaciated areas. These trends have previously been identified as characteristic of parthenogenetic animals as well. While many authors have interpreted these trends as providing support for the 'biotic uncertainty' hypothesis for the maintenance of sex, these trends are consistent with several other interpretations as well. Furthermore, all of these interpretations have ignored the positive correlation that exists between ploidy level and breeding system: asexual plant and animal taxa are generally polyploid, while their sexual relatives are generally diploid. Evidence is presented for plants, and by extension for animals as well, that high ploidy levels alone-independent of breeding system-could endow individuals with the ability to tolerate these 'extreme' environments. For this reason, it appears premature to interpret observed distribution patterns as evidence to support hypotheses about what forces maintain sexual reproduction. Only experimental tests, using sexuals and asexuals of comparable ploidy levels, can permit us to discriminate among the alternatives.
Topics: Ecology; Parthenogenesis; Plants; Ploidies
PubMed: 2961597
DOI: 10.1007/978-3-0348-6273-8_9 -
Annals of Botany Feb 2023Oil palms showing exceptional vigour and dubbed as 'giant palms' were identified in some progeny during breeding. A panel of phenotypical traits were studied to...
BACKGROUND AND AIMS
Oil palms showing exceptional vigour and dubbed as 'giant palms' were identified in some progeny during breeding. A panel of phenotypical traits were studied to characterize these trees. The hypothesis that gigantism and other anomalies might be linked to polyploidy was investigated.
METHODS
Twenty sib pairs of palms from different crosses, each comprising a giant and a normal oil palm, were studied by flow cytometry with rice 'Nipponbare' as standard reference. In parallel, palms were assessed in the field using 11 phenotypic traits. A principal component analysis (PCA) was conducted to define relationships between these phenotypical traits, and a linear discriminant analysis (LDA) to predict ploidy level and giant classification. Finally, a co-dominant molecular marker study was implemented to highlight the sexual process leading to the formation of 2n gametes.
KEY RESULTS
The first group of oil palms presented an oil palm/rice peak ratio of around 4.8 corresponding to diploid oil palms, whereas the second group presented a ratio of around 7, classifying these plants as triploid. The PCA enabled the classification of the plants in three classes: 21 were normal diploid palms; ten were giant diploid palms; while 11 were giant triploid palms. The LDA revealed three predictors for ploidy classification: phyllotaxy, petiole size and circumference of the plant, but surprisingly not height. The molecular study revealed that triploid palms arose from 2n gametes resulting from the second division restitution of meiosis in parents.
CONCLUSIONS
This study confirms and details the process of sexual polyploidization in oil palm. It also identifies three phenotypical traits to assess the ploidy level of the giant oil palms in the field. In practical terms, our results provide a cheap scientific method to identify polyploid palms in the field.
Topics: Triploidy; Crosses, Genetic; Ploidies; Diploidy; Phenotype; Arecaceae
PubMed: 35299242
DOI: 10.1093/aob/mcac036 -
Nature Communications Mar 2021Liver cancer typically arises after years of inflammatory insults to hepatocytes. These cells can change their ploidy state during health and disease. Whilst polyploidy...
Liver cancer typically arises after years of inflammatory insults to hepatocytes. These cells can change their ploidy state during health and disease. Whilst polyploidy may offer some protection, new research shows it may also promote the formation of liver tumours.
Topics: Humans; Liver Neoplasms; Ploidies; Polyploidy
PubMed: 33767143
DOI: 10.1038/s41467-021-21897-8 -
Plant Physiology Oct 2022Whole-genome duplication generates a tetraploid from a diploid. Newly created tetraploids (neo-tetraploids) of Arabidopsis (Arabidopsis thaliana) have elevated leaf...
Whole-genome duplication generates a tetraploid from a diploid. Newly created tetraploids (neo-tetraploids) of Arabidopsis (Arabidopsis thaliana) have elevated leaf potassium (K), compared to their diploid progenitor. Micro-grafting has previously established that this elevated leaf K is driven by processes within the root. Here, mutational analysis revealed that the K+-uptake transporters K+ TRANSPORTER 1 (AKT1) and HIGH AFFINITY K+ TRANSPORTER 5 (HAK5) are not necessary for the difference in leaf K caused by whole-genome duplication. However, the endodermis and salt overly sensitive and abscisic acid-related signaling were necessary for the elevated leaf K in neo-tetraploids. Contrasting the root transcriptomes of neo-tetraploid and diploid wild-type and mutants that suppress the neo-tetraploid elevated leaf K phenotype allowed us to identify a core set of 92 differentially expressed genes associated with the difference in leaf K between neo-tetraploids and their diploid progenitor. This core set of genes connected whole-genome duplication with the difference in leaf K between neo-tetraploids and their diploid progenitors. The set of genes is enriched in functions such as cell wall and Casparian strip development and ion transport in the endodermis, root hairs, and procambium. This gene set provides tools to test the intriguing idea of recreating the physiological effects of whole-genome duplication within a diploid genome.
Topics: Tetraploidy; Potassium; Gene Regulatory Networks; Arabidopsis; Ploidies; Plant Leaves
PubMed: 35929797
DOI: 10.1093/plphys/kiac360 -
PeerJ 2023, which is common in China's Hainan Province, is an important woody olive tree species. Due to many years of geographic isolation, has not received the attention it...
, which is common in China's Hainan Province, is an important woody olive tree species. Due to many years of geographic isolation, has not received the attention it deserves, which limits the exploitation of germplasm resources. Therefore, it is necessary to study population genetic characteristics for further utilization and conservation of . In this study, 96 individuals in six wild populations were used for ploidy analysis of the chromosome number, and the genetic diversity and population structure were investigated using 12 pairs of SSR primers. The results show complex ploidy differentiation in species. The ploidy of wild includes tetraploid, pentaploid, hexaploid, heptaploid, octoploid and decaploid species. Genetic analysis shows that genetic diversity and genetic differentiation among populations are low. Populations can be divided into two clusters based on their genetic structure, which matches their geographic location. Finally, to further maintain the genetic diversity of , ex-situ cultivation and in-situ management measures should be considered to protect it in the future.
Topics: Humans; Genetic Drift; Ploidies; Tetraploidy; Camellia; Genetic Structures
PubMed: 36852222
DOI: 10.7717/peerj.14756 -
FEMS Yeast Research Aug 2006Many of the difficulties of studying evolution in action can be surmounted using populations of microorganisms, such as yeast. A readily manipulated sexual system and an... (Review)
Review
Many of the difficulties of studying evolution in action can be surmounted using populations of microorganisms, such as yeast. A readily manipulated sexual system and an increasingly sophisticated array of molecular and genomic tools uniquely qualify Saccharomyces cerevisiae as an experimental subject. This minireview briefly describes some recent contributions of yeast experiments to current understanding of the evolution of ploidy, sex, mutation, and speciation.
Topics: Evolution, Molecular; Mutation; Ploidies; Yeasts
PubMed: 16879420
DOI: 10.1111/j.1567-1364.2006.00061.x -
Current Biology : CB Mar 2018Changes in ploidy are relatively rare, but play important roles in the development of cancer and the acquisition of long-term adaptations. Genome duplications occur...
Changes in ploidy are relatively rare, but play important roles in the development of cancer and the acquisition of long-term adaptations. Genome duplications occur across the tree of life, and can alter the rate of adaptive evolution. Moreover, by allowing the subsequent loss of individual chromosomes and the accumulation of mutations, changes in ploidy can promote genomic instability and/or adaptation. Although many studies have been published in the last years about changes in chromosome number and their evolutionary consequences, tracking and measuring the rate of whole-genome duplications have been extremely challenging. We have systematically studied the appearance of diploid cells among haploid yeast cultures evolving for over 100 generations in different media. We find that spontaneous diploidization is a relatively common event, which is usually selected against, but under certain stressful conditions may become advantageous. Furthermore, we were able to detect and distinguish between two different mechanisms of diploidization, one that requires whole-genome duplication (endoreduplication) and a second that involves mating-type switching despite the use of heterothallic strains. Our results have important implications for our understanding of evolution and adaptation in fungal pathogens and the development of cancer, and for the use of yeast cells in biotechnological applications.
Topics: Adaptation, Physiological; Diploidy; Gene Duplication; Genes, Mating Type, Fungal; Genome, Fungal; Genomic Instability; Haploidy; Mutation; Ploidies; Saccharomyces cerevisiae; Yeasts
PubMed: 29502947
DOI: 10.1016/j.cub.2018.01.062 -
Human Reproduction (Oxford, England) Dec 2023
Topics: Humans; Artificial Intelligence; Ploidies; Embryo, Mammalian
PubMed: 37877410
DOI: 10.1093/humrep/dead223 -
Molecular Ecology Jun 2023Polyploids recurrently emerge in angiosperms, but most polyploids are likely to go extinct before establishment due to minority cytotype exclusion, which may be...
Polyploids recurrently emerge in angiosperms, but most polyploids are likely to go extinct before establishment due to minority cytotype exclusion, which may be specifically a constraint for dioecious plants. Here we test the hypothesis that a stable sex-determination system and spatial/ecological isolation facilitate the establishment of dioecious polyploids. We determined the ploidy levels of 351 individuals from 28 populations of the dioecious species Salix polyclona, and resequenced 190 individuals of S. polyclona and related taxa for genomic diversity analyses. The ploidy survey revealed a frequency 52% of tetraploids in S. polyclona, and genomic k-mer spectra analyses suggested an autopolyploid origin for them. Comparisons of diploid male and female genomes identified a female heterogametic sex-determining factor on chromosome 15, which probably also acts in the dioecious tetraploids. Phylogenetic analyses revealed two diploid clades and a separate clade/grade of tetraploids with a distinct geographic distribution confined to western and central China, where complex mountain systems create higher levels of environmental heterogeneity. Fossil-calibrated phylogenies showed that the polyploids emerged during 7.6-2.3 million years ago, and population demographic histories largely matched the geological and climatic history of the region. Our results suggest that inheritance of the sex-determining system from the diploid progenitor as intrinsic factor and spatial isolation as extrinsic factor may have facilitated the preservation and establishment of polyploid dioecious populations.
Topics: Humans; Tetraploidy; Diploidy; Phylogeny; Biological Evolution; Polyploidy
PubMed: 36843569
DOI: 10.1111/mec.16902