The genus Holoaden includes three species described so far, but the only published cytogenetic data is from Holoaden bradei, with the karyotype 2n = 18, based on conventional staining. In the present paper we report, for the first time, data on chromosomes of H. luederwaldti, which presented 2n = 18 and a case of natural triploidy, with 2n = 3x = 27. In this sample, another karyotypic variation was observed due to the occurrence of two types of chromosome 8, which present submetacentric or subtelocentric morphologies. Homomorphic subtelocentric or heteromorphic condition was observed among the diploid specimens, whereas the triploid had one submetacentric and two subtelocentric chromosomes 8. In all specimens, Ag-NOR was located in the long arms of chromosomes 8, at the interstitial region when subtelocentric, or in the proximal region when submetacentric, confirmed by fluorescent in situ hybridization with the HM123 probe. The C bands showed centromeric distribution and distribution at Ag-NOR site. The centromeric heterochromatin was fluorescent with DAPI staining, whereas the Ag- NOR displayed bright fluorescence with CMA3. Fluorescent in situ hybridization using a telomeric probe labelled exclusively the telomere regions. Although the same 2n = 18 chromosome numbers have been observed in H. luederwaldti and H. bradei, some differences in both karyotypes can be visualized, mainly with regard to the morphology of the last chromosome pairs.
Prípad vzácnej triploidie 69, XXY u živorodeného plodu hmotnosti 760 g. Diagnóza bola stanovená na základe cytogenetického vyšetrenia post mortem.
Triploidy 69, XXY was described in a livebom foetus weighing 760 g. Diagnosis was based on postmortal cytogenetical analysis.
- MeSH
- Chromosome Aberrations MeSH
- Abortion, Induced MeSH
- Karyotyping MeSH
- Humans MeSH
- Hydatidiform Mole genetics MeSH
- Infant, Premature, Diseases genetics MeSH
- Infant, Newborn MeSH
- Polyploidy MeSH
- Abortion, Spontaneous MeSH
- Check Tag
- Humans MeSH
- Infant, Newborn MeSH
- Publication type
- Case Reports MeSH
We report for the first time, a comparison of two approaches for artificially induced triploidy in zebrafish (Danio rerio) using cold shock and heat shock treatments. Of the two methods, heat shock treatment proved more effective with a triploid production rate of 100% in particular females. Subsequently, triploid zebrafish larvae were used as recipients for intraperitoneal transplantation of ovarian and testicular cells originating from vas:EGFP strain in order to verify their suitability for surrogate reproduction. Production of donor-derived sperm was achieved in 23% of testicular cell recipients and 16% of ovarian cell recipients, indicating the suitability of triploids as surrogate hosts for germ cell transplantation. Success of the transplantation was confirmed by positive GFP signal detected in gonads of dissected fish and stripped sperm. Germline transmission was confirmed by fertilization tests followed by PCR analysis of embryos with GFP specific primers. Reproductive success of germline chimera triploids evaluated as fertilization rate and progeny development was comparable to control groups.
- MeSH
- Breeding methods MeSH
- Zebrafish genetics MeSH
- Genetic Engineering methods veterinary MeSH
- Flow Cytometry MeSH
- Temperature MeSH
- Triploidy * MeSH
- Germ Cells transplantation MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Comparative Study MeSH
Interspecific hybridization, polyploidization and transitions from sexuality to asexuality considerably affect organismal genomes. Especially the last mentioned process has been assumed to play a significant role in the initiation of chromosomal rearrangements, causing increased rates of karyotype evolution. We used cytogenetic analysis and molecular dating of cladogenetic events to compare the rate of changes of chromosome morphology and karyotype in asexually and sexually reproducing counterparts in European spined loach fish (Cobitis). We studied metaphases of three sexually reproducing species and their diploid and polyploid hybrid clones of different age of origin. The material includes artificial F1 hybrid strains, representatives of lineage originated in Holocene epoch, and also individuals of an oldest known age to date (roughly 0.37 MYA). Thereafter we applied GISH technique as a marker to differentiate parental chromosomal sets in hybrids. Although the sexual species accumulated remarkable chromosomal rearrangements after their speciation, we observed no differences in chromosome numbers and/or morphology among karyotypes of asexual hybrids. These hybrids possess chromosome sets originating from respective parental species with no cytogenetically detectable recombinations, suggesting their integrity even in a long term. The switch to asexual reproduction thus did not provoke any significant acceleration of the rate of chromosomal evolution in Cobitis. Asexual animals described in other case studies reproduce ameiotically, while Cobitis hybrids described here produce eggs likely through modified meiosis. Therefore, our findings indicate that the effect of asexuality on the rate of chromosomal change may be context-dependent rather than universal and related to particular type of asexual reproduction.
- MeSH
- Biological Evolution * MeSH
- Diploidy * MeSH
- Karyotype * MeSH
- Cypriniformes genetics MeSH
- Reproduction, Asexual genetics MeSH
- Triploidy * MeSH
- Animals MeSH
- Check Tag
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Moths and butterflies (Lepidoptera) have sex chromosome systems with female heterogamety, and 2 models, W-dominance and Z-counting, have been proposed to determine sex. The W-dominant mechanism is well known in Bombyx mori. However, little is known about the Z-counting mechanism in Z0/ZZ species. We investigated whether ploidy changes affect sexual development and gene expression in the eri silkmoth, Samia cynthia ricini (2n = 27♀/28♂, Z0♀/ZZ♂). Tetraploid males (4n = 56, ZZZZ) and females (4n = 54, ZZ) were induced by heat and cold shock, and then, triploid embryos were produced by crosses between diploids and tetraploids. Two karyotypes (3n = 42, ZZZ and 3n = 41, ZZ) were identified in triploid embryos. Triploid embryos with 3 Z chromosomes showed male-specific splicing of the S. cynthia doublesex (Scdsx) gene, whereas 2-Z triploid embryos showed both male- and female-specific splicing. From larva to adult, 3-Z triploids showed a normal male phenotype, except for defects in spermatogenesis. However, abnormal gonads were observed in 2-Z triploids, which showed both male- and female-specific Scdsx transcripts not only in the gonads but also in somatic tissues. Two-Z triploids were thus obviously intersexes, suggesting that sexual development in S. c. ricini depends on the Z:A ratio and not only on the Z number. Moreover, mRNA-seq analyses in embryos showed that relative levels of gene expression are similar between samples with different doses of Z chromosomes and autosome sets. Our results provide the first evidence that ploidy changes disrupt sexual development but have no effect on the general mode of dosage compensation in Lepidoptera.
Comparative image cytometry of erythrocytes of diploid and triploid tench Tinca tinca L. and evolutionary tetraploid sterlet Acipenser ruthenus L. was performed on whole live unstained cells, live cells with stained nuclei and on stained fixed whole cells and their nuclei to test if erythrocyte measurements made from blood smears reflect the true dimensions of live cells. Nuclear area and perimeter were the best ploidy level predictors distinguishing accurately among live and fixed diploid, triploid and tetraploid cells, without significant differences between live and fixed cells within a ploidy level. Redundancy analysis revealed insignificant marginal effect of fixation (explained 2.3% of variation, F = 0.804), whereas the effect of ploidy level was highly significant (explained 50.6% of variation, F = 34.874). The erythrocyte measurements of diploid, triploid and tetraploid fish erythrocytes and their nuclei made from blood smears reflect the true dimensions of live cells, and the fixation procedure did not substantially affect their predictive value for ploidy level determination.
- MeSH
- Diploidy MeSH
- Erythrocytes cytology MeSH
- Image Cytometry MeSH
- Fishes blood MeSH
- Tetraploidy MeSH
- Triploidy MeSH
- Cell Size MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Comparative Study MeSH
BACKGROUND: Carassius auratus complex is an extraordinary species complex including the diploid and polyploid forms exhibiting asexual and sexual reproduction modes. The coexistence of both forms in the same habitats is currently reported. The stable coexistence of asexual and sexual forms assumes some disadvantages for asexuals that balance the costs of sex. In our study, we hypothesized and tested the differences in physiological (including heamatological and immunological), growth-related, condition-related, and fitness-related traits between gynogenetic females and sexuals. RESULTS: Our results revealed similar growth performance in gynogenetic females and sexuals measured by body size and weight, or expressed by condition factor. The energy allocation in reproduction measured by the relative size of gonads revealed no difference between gynogenetic and sexual females; in addition, both females in spawning expressed the same estradiol levels in blood plasma. We found a gender specific trade-off between investment in reproduction and immunocompetence (measured by the spleen-somatic index). Higher aerobic performance expressed by the heart index and higher oxygen-carrying capacity were found in sexual males, with increasing values before and during spawning. Our study evidenced significantly lower aerobic performance but higher oxygen-carrying capacity per erythrocyte in gynogenetic females when compared to sexuals. IgM production differed between gynogens and sexuals of C. auratus complex. CONCLUSIONS: Our study indicates that a similar amount of energy is invested by both gynogenetic and sexual females of C. auratus complex in reproductive behaviour. We suggest that lower aerobic performance in gynogens may represent their physiological disadvantage balancing the cost of sexual reproduction. A trade-off between the number of erythrocytes and the oxygen-carrying capacity per erythrocyte in sexual males and gynogenetic females may contribute to the coexistence of gynogenetic and sexual forms. In addition, the differences in specific immunity between gynogens and sexuals may also reduce the evolutionary disadvantage of sexual reproduction. In conclusion, we propose that several mechanisms contribute to the coexistence of the gynogenetic-sexual C. auratus complex.
- MeSH
- Biological Evolution MeSH
- Diploidy MeSH
- Ecosystem MeSH
- Goldfish anatomy & histology genetics immunology physiology MeSH
- Reproduction MeSH
- Triploidy MeSH
- Aquaculture economics MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Edible banana cultivars are diploid, triploid, or tetraploid hybrids, which originated by natural cross hybridization between subspecies of diploid Musa acuminata, or between M. acuminata and diploid Musa balbisiana. The participation of two other wild diploid species Musa schizocarpa and Musa textilis was also indicated by molecular studies. The fusion of gametes with structurally different chromosome sets may give rise to progenies with structural chromosome heterozygosity and reduced fertility due to aberrant chromosome pairing and unbalanced chromosome segregation. Only a few translocations have been classified on the genomic level so far, and a comprehensive molecular cytogenetic characterization of cultivars and species of the family Musaceae is still lacking. Fluorescence in situ hybridization (FISH) with chromosome-arm-specific oligo painting probes was used for comparative karyotype analysis in a set of wild Musa species and edible banana clones. The results revealed large differences in chromosome structure, discriminating individual accessions. These results permitted the identification of putative progenitors of cultivated clones and clarified the genomic constitution and evolution of aneuploid banana clones, which seem to be common among the polyploid banana accessions. New insights into the chromosome organization and structural chromosome changes will be a valuable asset in breeding programs, particularly in the selection of appropriate parents for cross hybridization.
- MeSH
- Musa genetics growth & development MeSH
- Chromosomes, Plant genetics MeSH
- Diploidy MeSH
- Karyotype MeSH
- Chromosome Painting methods MeSH
- Evolution, Molecular MeSH
- Plant Breeding MeSH
- Tetraploidy MeSH
- Translocation, Genetic MeSH
- Triploidy MeSH
- Crops, Agricultural genetics growth & development MeSH
- Publication type
- Journal Article MeSH
- Comparative Study MeSH
BACKGROUND: A cytogenetic analysis of the new local triploid population of the caryophyllidean tapeworm Atractolytocestus huronensis, a unique parthenogenetic species with the ability to colonise new regions, was performed to understand the inner structure of its chromosome complement. METHODS: A karyotype analysis was carried out using classical Giemsa staining and C-banding combined with fluorescent DAPI staining. A hypothesis that triplets are composed from three homologue chromosomes of approximately the same length and same centromere position was tested statistically for multiple dependent variables using a non-parametric Friedman's ANOVA. The chromosomal location of ribosomal DNA clusters within the nucleolar organization region (NORs) and telomeric (TTAGGG)n sequences were detected by fluorescent in situ hybridization (FISH). Chromosomes were subjected to AgNO3 staining in order to determine whether the rDNA sites represent active NORs. RESULTS: The cytogenetic analysis confirmed the karyotype composed from eight chromosome triplets (3n = 24) as well as the existence of a pair of NORs located on each chromosome of the second triplet. Six NORs varied their activity from cell to cell, and it was reflected in the numbers of nucleoli (from 1 to 5). A huge morphological diversification of homologue chromosomes was originally detected in six out of eight triplets; the homologue elements differed significantly either in length and/or morphology, and some of them carried discernible interstitial telomeric sequences (ITSs), while the end telomeres were minute. The heterochromatin bands with high AT content varied irregularly, and the course of aberrant spermatogenesis was evident. CONCLUSIONS: Diversification of homologues is a unique phenomenon very likely caused by the long-term absence of a recombination and consequential accumulation of chromosome rearrangements in the genome of A. huronensis during species evolution. Unalterable asexual reproduction of the tapeworm, along with international trade in its host (carp), is facilitating its ongoing spread.
- MeSH
- Cestoda classification genetics physiology MeSH
- Chromosomes MeSH
- Carps parasitology MeSH
- Karyotyping MeSH
- Fish Diseases parasitology MeSH
- Reproduction MeSH
- Spermatocytes cytology MeSH
- Triploidy MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
