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Results for “karyotype evolution”

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At least 19 recordsLinked to original sources
PubMed2025

Genomic insights into karyotype evolution and adaptive mechanisms in Polygonaceae species.

Polygonaceae, with ecological versatility and global distribution, is an ideal system for investigating plant adaptation. However, the genomic mechanisms underlying its karyotype evolution and environmental resilience remain unclear. We herein present chromosome-level genomes of 11 species from 10 Polygonaceae genera. Our analyses reveal that Gypsy retrotransposons are key drivers of genome size variations in Polygonaceae. We reconstructed a Polygonaceae ancestral karyotype comprising 28 proto-chromosomes and elucidated evolutionary trajectories via extensive chromosomal rearrangements. Furthermore, we constructed a cross-genus super pan-genome for Polygonaceae, identifying 80,055 gene families, of which 9,845 (12.30%) are core gene families. Private genes are found to contribute significantly to interspecific differences in adaptability. Notably, gene copy number variations are identified as a critical factor influencing adaptations to diverse niches involving species-specific increases in metabolic pathways. This study provides a genomic framework for Polygonaceae karyotype plasticity and adaptive innovation, offering insights into plant evolution under environmental challenges.

Karyotype↗
PubMed1979

Karyotypic evolution associated with loss of tumorigenicity.

A reproducible association between loss of tumorigenicity and specific karyotypic changes was described in cell culture lines SLU-5 and DMS-402 established from mouse plasmacytoma MOPC-21 carried in BALB/c mice. The defect in chromosome no. 15, which has been specifically associated with mouse myelomas, was neither corrected nor eliminated in the karyotypic evolution that occurred simultaneously and progressively with the grandual loss of oncogenicity.

Animals↗
PubMed1979

Karyotype evolution of the simian virus 40--transformed human cell line LNSV.

We have used trypsin-Wright's banding ("GTG-banding") to analyze the chromosome content in two sublines of the SV40-transformed human cell line LNSV, derived from fibroblasts of a patient with HPRT deficiency. Both LNSV sublines (GM-847 and "LNSV") were heteroploid and showed considerable numerical and structural chromosome variability. Nineteen rearranged chromosomes which were observed at high frequency have been set aside as "marker chromosomes," and their probable derivation from normal human chromosomes has been described in PARIS CONFERENCE (1971) nomenclature. Heterogeneity within these uncloned sublines appears to increase with time in culture, and no evidence was found for evolution of a karyotypically stable cell population. The results are of general significance for cell genetic studies using established cell lines.

Cell Line↗
PubMed1976

Non-random karyotypic evolution in chronic myeloid leukemia.

The chromosome banding pattern was analyzed in bone-marrow cells and/or spleen cells of 10 patients in the blastic phase of chronic myeloid leukemia (CML). It was obvious from the karyotype analysis that the chromosome aberrations occurring addition to the Philadelphia chromosome (Ph1) were strictly non-random. An extra Ph1, trisomy 8 and/or trisomy for the long arm of chromosome 17 were observed in all cases. This consistent pattern of chromosome involvement in CML was confirmed in 57 cases from the literature studied with banding techniques. In 88% of the total number of cases with further changes at least one of the three main chromosomal aberrations was found ("major route" of karyotypic evolution).

Adult↗
PubMedDate not supplied

[Swine cell sublines with different ploidies. I. Karyotypic evolution].

Two swine kidney cell sublines, one of them IB-RS-10-I, with diploid level of chromosomes and the other, IB-RS-10-II, with tetraploid level, were studied as far as their morphology and karyotypic evolution was concerned. Both of them derived from the parental cell line after seven months in continuous culture and maintained in the same type of nutrient medium showed peculiar chromosome alterations for each subline, though in both sublines were observed losses of chromosomes belonging to the gruop GIV.

Animals↗
PubMed1975

Certain patterns of karyotype evolution in chronic myelogeneous leukaemia. Chromosome abnormalities in CML.

The study of chromosome banding pattern of leukaemic cells in 15 patients with CML revealed t(9;22) in all cases. Similar additional chromosome abnormalities were observed in the terminal stage of the disease in 5 of 9 patients with aneuploid cell lines. The most frequent abnormalities were i(17q) and trisomy 8. The regularities of karyotype evolution in the terminal stage of CML are discussed.

Adult↗
PubMed1978

Karyotypic evolution in an originally XY cell line of Drosophila melanogaster: a case of heterochromatin increase in vitro.

The cell line Ca of Drosophila melanogaster, characterized initially by a nearly diploid and normal male karyotype (XY), was used to study chromosomal variation over a period of 5 years of cultivation in vitro. Some general aspects of cell population dynamics which are in accordance with previous findings are pointed out. Various phenomena regarding chromosomal changes leading to karyotype polymorphism are outlined, with a particular emphasis being given to the sex chromosomes. Accordingly, with the aid of fluorescence analysis, some features of the Y and the X chromosomes providing evidence of an enlargement of the heterochromatin (due to addition and to saltatory replication) are described. Moreover, a case of variation in cell morphology accompanied by karyotypic changes was observed, as well as the emergence of a new cell subline of XX type derived from the original of XY type.

Cell Line↗
PubMed1976

Karyotype evolution in cell lines of Drosophila melanogaster.

The chromosomal changes occurred in two independent cell lines (GM2 and GM3) of Drosophila melanogaster maintained in medium supplemented with serum and in serum-free medium were compared. In both culture conditions and in both lines a chromosomal evolution was revealed. Structural and numerical variations were analysed. The breaks giving rise to rearrangements were at heterochromatic level. Moreover, a tetraploidisation followed by loss of chromosomes or of portions of chromosomes recalls an analogous cycle observed in human cells.

Animals↗
PubMed1977

Chromosomes and causation of human cancer and leukemia. XXVI. Binding studies in acute lymphoblastic leukemia (ALL).

Chromosomes were studied in the bone marrow cells of 101 patients with acute lymphoblastic leukemia (ALL) hospitalized at or attending the clinics of Roswell Park Memorial Institute (RPMI) between January, 1968, and December, 1976. Aneuploidy was observed in about 50% (54/101) of the cases. Two cases were hypodiploid and the remaining were either pseudo or hyperdiploid. The frequency of abnormalities and the chromosomal numbers were similar to those of 106 cases studied in our laboratory prior to 1968. Of 50 recently unselected cases of ALL in whom Q- and G-banded karyotypes were attempted, 31 were successfully analyzed with these techniques. The banding patterns revealed 16 cases to have chromosome abnormalities and four of these to have a similar abnormality, i.e., partial deletion of the long arm of chromosome no. 6: two cases had a 6q- with additional abnormalities and two had 6q- as the sole karyotypic abnormality. The breakpoint in chromosome no. 6 seemed to involve a segment from q21 to q25. An isochromosome of the long arm of no. 7, i(7q), was observed in two cases, two additional no. 21 chromosomes were observed in five cases and, except for the Y, all other chromosomes participated in the karyotypic changes encountered in the 16 cases in which banding analyses were performed. Banding analysis has afforded the first reliable approach towards ascertaining karyotypic evolution in ALL, which was achieved in eight cases of the present study. The chromosomes contributing to this karyotypic evolution were distributed widely. Thus, all chromosomes except the Y participated in numerical and/or structural karyotypic changes. Even though nonrandom chromosome changes may occur early in ALL, the pristine prototypic picture of the karyotypes in ALL is often obfuscated by successive chromosomal changes and hyperdiploidy by the time the karyotypes are analyzed in this condition. Further cytogenetic studies are required, with special attention to karyotypic evolution, in order to uncover the significance of chromosomal changes in early and late ALL.

Adolescent↗
PubMed2025

Subgenomic divergence and functional innovation following whole-genome duplication in Maleae species of Rosaceae.

Whole-genome duplication (WGD) drives plant evolution by inducing karyotype rearrangements and gene loss through subgenome fractionation. In this study, we investigate post-WGD evolutionary dynamics in Rosaceae, focusing on Maleae species, which uniquely experienced an additional WGD. Using phylogenetic and synteny analyses, we reveal that chromosomal breakpoints act as hotspots for localized fractionation, contributing to blurred homoeologous origins and influencing gene retention patterns. Here, we reconstruct karyotype evolution across Rosaceae subfamilies, highlighting chromosome reductions and lineage-specific rearrangements in Dryadoideae, Rosoideae, and Amygdaloideae. We also identify a bias for retaining transcription factors and hormone-related genes from older WGDs in subsequent polyploidy events. Transcriptome analysis classifies WGD-derived genes in Maleae species, such as apple and loquat, into three expression groups, with hormone-enriched genes playing roles in lignification and fruit-related innovations. These findings demonstrate the interplay between chromosomal breakpoints, biased retention, and functional divergence, revealing their contributions to genomic and phenotypic evolution in Maleae and their adaptive success within Rosaceae.

Genome, Plant↗
PubMed1976

[New data on non-parallel evolution of karyotype and morphology in Phyllotinae (Rodents, Cricetidae)].

The non-concordance of the morphological and chromosomal evolution in the Phyllotinae is discussed in the light of the latest karyological data concerning the genus Zygodontomys: individual specimens of this genus from French Guiana present a new chromosomal formula with a high number 2 N; their karyotypical and morphological peculiarities are sufficient to warrant creating a new species Z. reigi. The great variability of the karyotypes appearing in this genus permits one to think that the various groups could represent successive aspects of the same chromosomal evolution, an increase of the number 2 N preceding an eventual decrease.

Animals↗
PubMed1979

Evolution of karyotypes in Philadelphia (Ph1) chromosome-negative chronic myelogenous leukemia.

Ten of 55 patients with chronic myelogenous leukemia (CML) diagnosed between 1972 and 1977 were found to lack the Philadelphia (Ph1) chromosome. Serial clinical, morphologic, and cytogenetic studies of patients with Ph1-negative CML showed that 30% of them had chromosomal abnormalities. Two had an extra chromosome No. 8 at the time of blast crisis, with a morphological picture of myeloblasts in the bone marrow. A third patient had a 6:14 translocation initially Abnormalities of chromosome No. 14 are frequently seen in lymphoproliferative disorders, and the bone marrow and peripheral blood contained a significant population of lymphoblasts as well as myeloblasts. The median survival for the 10 patients was 19 months. The exact nature of Ph1-negative CML is not yet clear; disease appears to be a distinct entity among the myeloproliferative disorders.

Aged↗
PubMed2026

Chromosome painting in plants: history and future perspectives.

Chromosome painting was developed in mammalian species nearly four decades ago and rapidly became a powerful tool for chromosome identification, comparative cytogenetics, and evolutionary genome analysis. Comparative chromosome painting among diverse mammals generated much of the foundational knowledge of chromosome structure, chromosomal rearrangements, and karyotype evolution before the advent of whole-genome sequencing. Although chromosome painting was first demonstrated in plants in 2001, its applications remained largely restricted to a few plant lineages until the development of oligonucleotide (oligo)-based chromosome painting in 2015. During the last decade, oligo-based chromosome painting has transformed plant cytogenetics, enabling many investigations that were previously impossible. These studies have provided new insights into meiotic chromosome pairing, crossover formation, chromosome fusion, karyotype stability, and chromosome evolution across diverse plant lineages. This review summarizes the history of technological development of chromosome painting in plants, highlights major discoveries enabled by oligo-based chromosome painting, and discusses future opportunities, particularly the integration of chromosome painting with three-dimensional chromosome and genome biology.

Chromosome Painting↗
PubMed2026

Highly Contiguous Is Not Chromosomally Accurate: Integrated Cytogenetic and Genomic Mapping in Two Turtle Genome.

High-quality genome assemblies are essential for robust research across biological and medical fields. Assembly errors can have far-reaching consequences for downstream analyses, including gene annotation and the inference of synteny. In contrast to the rapid growth of genomic data volume, there is a notable lag in the integration of chromosome-level assemblies with cytogenetic data. We conducted the first direct genome-to-genome comparison, integrating comparative chromosome painting, the alignment of chromosome-specific probes to available genome assemblies, and synteny-based comparison of independent chromosome-level assemblies of the loggerhead sea turtle (Caretta caretta, 2n = 56) and the red-eared slider (Trachemys scripta elegans, 2n = 50). Using two independent sets of flow-sorted chromosome-specific probes in cross-species hybridizations, together with the sequencing and mapping of chromosome-derived DNA libraries, we assigned assembled scaffolds to all physical chromosomes of both species. In C. caretta, chromosomal assignments and genome-wide synteny were fully consistent with the published assembly, except for the reduced sizes of two microchromosome scaffolds, which we attribute to under-representation of repetitive DNA. In contrast, in T. s. elegans, cytogenetic validation of the assemblies revealed a false rearrangement compared to a missed one. Our results show that even highly contiguous vertebrate genome assemblies can misrepresent chromosome structure. When cytogenetic analyses reveal such inaccuracies, updated reference genomes should be generated for widely studied species to enable accurate inference of karyotype evolution and downstream comparative genomic analyses.

FISH↗
PubMed1977

Chromosomal repatterning in Acrididae.

Studies on the chromosomes of the acridid grasshoppers Acrida turrita, Poekilocerus pictus and Chrotogonus oxypterus have led the authors to surmise that structural re-arrangements must have played a major role in chromosomal repatterning and karyotypic evolution. Moreover, the telocentricity noticed in the Cryptosacci was evident in the Chasmosacci without the presence of the metacentric chromosomes to account for the reduction in the chromosome number. Possible trends in the evolution are discussed.

Animals↗