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.
- MeSH
- bourec * genetika MeSH
- motýli * genetika MeSH
- můry * genetika MeSH
- sexuální vývoj MeSH
- triploidie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
OBJECTIVES: We tested the toxicity of ethinylestradiol, a semisynthetic estrogen used in oral contraceptives, on all-male triploid zebrafish using commercial feeds and three different doses concentrations. We aimed to determine whether ethinylestradiol peroral administration resulted in vitellogenin production and whether all-male triploid zebrafish could serve as a model species for xenoestrogen testing. METHODS: The actual concentrations of 17α-ethinylestradiol were 0.0035 (low); 0.0315 (medium) and 0.365 (high) μg/g. Positive control represented commercial feeds containing 0.0465 μg/g of β-estradiol. The experiment lasted 8 weeks. RESULTS: Our results indicate that 17α-ethinylestradiol consumption does induce vitellogenin production in triploid zebrafish. CONCLUSIONS: The simple presence of vitellogenin is a definite symptom indicative of the potential for such changes due to the action of estrogenic substances. As such, this experiment has shown that the use of all-male triploid zebrafish populations, rather than the mixed-sex populations of other species previously used, could serve as a suitable alternative model population for controlled testing of the effects of xenoestrogens on fish.
The large-sized tapeworm Dibothriocephalus latus is known as the broad or fish-borne cestode of mammals that is capable to infect humans and cause diphyllobothriosis. Recently, molecular data on D. latus has been accumulating in the literature and a complete genome sequence has been published; however, little is known about the karyotype and chromosome architecture. In this study, an in-depth karyological analysis of 2 D. latus specimens was carried out. The plerocercoids originated from a perch caught in subalpine Lake Iseo (Italy) and the tapeworms were reared in hamsters. Both specimens contained cells with a highly variable number of chromosomes ranging from18 to 27. Nevertheless, the largest portion of mitotic figures (47%) showed a number corresponding to the triploid set, 3n = 27. Accordingly, the karyotype of the analyzed specimens consisted of 9 triplets of metacentric chromosomes. Fluorescence in situ hybridization (FISH) with the 18S rDNA probe clearly demonstrated the presence of 3 clusters of hybridization signals on the triplet of chromosome 7, thus confirming the triploid status of the specimens. FISH with a telomeric (TTAGGG)n probe confined hybridization signals exclusively to the terminal chromosomal regions, supporting the earlier findings that this repetitive motif is a conserved feature of tapeworm telomeres.
- MeSH
- chromozomy genetika MeSH
- cytogenetické vyšetření MeSH
- difylobotriáza parazitologie MeSH
- Diphyllobothrium genetika metabolismus MeSH
- hybridizace in situ fluorescenční MeSH
- karyotyp MeSH
- RNA helmintů analýza MeSH
- RNA ribozomální 18S analýza MeSH
- triploidie * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články 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
- banánovník genetika růst a vývoj MeSH
- chromozomy rostlin genetika MeSH
- diploidie MeSH
- karyotyp MeSH
- malování chromozomů metody MeSH
- molekulární evoluce MeSH
- šlechtění rostlin MeSH
- tetraploidie MeSH
- translokace genetická MeSH
- triploidie MeSH
- zemědělské plodiny genetika růst a vývoj MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
Although reproductive assurance has been suggested to be one of the most important factors shaping the differential distributional patterns between sexuals and asexuals (geographic parthenogenesis), it has only rarely been studied in natural populations of vascular plants with autonomous apomixis. Moreover, there are almost no data concerning the putative relationship between the level of apomictic versus sexual plant reproduction on one hand, and reproductive assurance on the other. We assessed the level of sexual versus apomictic reproduction in diploid and triploid plants of Hieracium alpinum across its distributional range using flow cytometric analyses of seeds, and compared the level of potential and realized seed set, i.e. reproductive assurance, between the two cytotypes under field and greenhouse conditions. Flow cytometric screening of embryos and endosperms of more than 4,100 seeds showed that diploids produced solely diploid progeny sexually, while triploids produced triploid progeny by obligate apomixis. Potential fruit set was much the same in diploids and triploids from the field and the greenhouse experiment. While in the pollination-limited environment in the greenhouse apomictic triploids had considerably higher realized fruit set than sexual diploids, there was no significant difference between cytotypes under natural conditions. In addition, sexuals varied to a significantly larger extent in realized fruit set than asexuals under both natural and greenhouse conditions. Our results indicate that triploid plants reproduce by obligate apomixis, assuring more stable and predictable fruit reproduction when compared to sexual diploids. This advantage could provide apomictic triploids with a superior colonisation ability, mirrored in a strong geographic parthenogenesis pattern observed in this species.
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
- chov metody MeSH
- dánio pruhované genetika MeSH
- genetické inženýrství metody veterinární MeSH
- průtoková cytometrie MeSH
- teplota MeSH
- triploidie * MeSH
- zárodečné buňky transplantace MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie 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 klasifikace genetika fyziologie MeSH
- chromozomy MeSH
- kapři parazitologie MeSH
- karyotypizace MeSH
- nemoci ryb parazitologie MeSH
- rozmnožování MeSH
- spermatocyty cytologie MeSH
- triploidie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The crucian carp Carassius carassius (Linnaeus, 1758), is native to many European freshwaters. Despite its wide distribution, the crucian carp is declining in both the number and sizes of populations across much of its range. Here we studied 30 individuals of a putative pure population from Helsinki, Finland. Despite clear external morphological features of C. carassius, an individual was of a higher ploidy level than the others. We therefore applied a set of molecular genetic (S7 nuclear and cytochrome b mitochondrial genes) and cytogenetic tools (sequential fluorescent 4', 6-diamidino-2-phenylindole [DAPI], Chromomycin A3 [CMA3], C-banding and in situ hybridization [FISH] with both 5S and 28S ribosomal DNA probes) to determine its origin. While all examined characteristics of a diploid representative male (CCAHe2Fi) clearly corresponded to those of C. carassius, a triploid individual (CCAHe1Fi) was more complex. Phylogenetic analysis revealed that the nuclear genome of CCAHe1Fi contained three haploid sets: two C. gibelio and one C. carassius. However the mitochondrial DNA was that of C. gibelio, demonstrating its hybrid origin. The FISH revealed three strong (more intensive) 5S rDNA loci, confirming the triploid status, and an additional 24 weak (less intensive) signals were observed in the chromosome complement of CCAHe1Fi. On the other hand, only two strong and 16 weak 5S rDNA signals were visible on the chromosomes of the CCAHe2Fi male. 28S rDNA FISH revealed four strong signals in both CCAHe1Fi and CCAHe2Fi individuals. CMA3 staining revealed four to six CMA3-positive bands of CCAHe1Fi, while that of diploids contained only two to four. The fact that a polyploid hybrid Carassius female with a strong invasive potential may share morphological characters typical for endangered C. carassius highlights a need to combine genetic investigations of Carassius cryptic diversity with conservation measures of C. carassius in Europe.
- MeSH
- diploidie MeSH
- druhová specificita MeSH
- fylogeneze MeSH
- genetická variace MeSH
- genetické markery MeSH
- hybridizace genetická MeSH
- hybridizace in situ fluorescenční MeSH
- kapři anatomie a histologie klasifikace genetika MeSH
- karyotyp MeSH
- ohrožené druhy MeSH
- pruhování chromozomů MeSH
- triploidie * MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Evropa MeSH
- Finsko 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.
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
- biologická evoluce MeSH
- diploidie MeSH
- ekosystém MeSH
- karas zlatý anatomie a histologie genetika imunologie fyziologie MeSH
- rozmnožování MeSH
- triploidie MeSH
- vodní hospodářství ekonomika MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
