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Comparative Cytogenetics 2023An account is given of my development of techniques to obtain well-spread Giemsa-stained banded chromosome preparations. Apparent G-banding could be obtained following...
An account is given of my development of techniques to obtain well-spread Giemsa-stained banded chromosome preparations. Apparent G-banding could be obtained following very slight trypsin treatment of freshly prepared slides, but this banding was very fine (close-grained) and possibly not a reflection of chromosome structure. However, treatment of developing embryos with 5-fluorouridine produced a similar chromomere banding, which is therefore regarded as genuine. Steady accumulation of Fabricius, 1775 karyotypes has resulted in the production of an Atlas covering 62 of the 170 species known to occur in the Palaearctic. Chromosome polymorphisms involving pericentric inversions and addition of extra C-banding regions have been found, as well as small B-chromosomes in a few species. In general, karyotypes have proved very useful in establishing the limits of individual species. Parthenogenesis involving triploidy has been found in two species. Karyotypes of experimentally produced hybrids have revealed irregularities in chromosome condensation.
PubMed: 38284104
DOI: 10.3897/compcytogen.17.112831 -
Current Zoology Apr 2023Despite numerous works devoted to hybrid origin of parthenogenesis in reptiles, the causes of hybridization between different species, resulting in the origin of... (Review)
Review
Despite numerous works devoted to hybrid origin of parthenogenesis in reptiles, the causes of hybridization between different species, resulting in the origin of parthenogenetic forms, remain uncertain. Recent studies demonstrate that sexual species considered parental to parthenogenetic rock lizards ( spp.) avoid interspecific mating in the secondary overlap areas. A specific combination of environmental factors during last glaciation period was critical for ectotherms, which led to a change in their distribution and sex ratio. Biased population structure (e.g., male bias) and limited available distributional range favored the deviation of reproductive behavior when species switched to interspecific mates. To date, at least 7 diploid parthenogenetic species of rock lizards (, Lacertidae) originated through interspecific hybridization in the past. The cytogenetic specifics of meiosis, in particular the weak checkpoints of prophase I, may have allowed the formation of hybrid karyotypes in rock lizards. Hybridization and polyploidization are 2 important evolutionary forces in the genus . At present, throughout backcrossing between parthenogenetic and parental species, the triploid and tetraploid hybrid individuals appear annually, but no triploid species found among spp. on current stage of evolution. The speciation by hybridization with the long-term stage of diploid parthenogenetic species, non-distorted meiosis, together with the high ecological plasticity of Caucasian rock lizards provide us with a new model for considering the pathways and persistence of the evolution of parthenogenesis in vertebrates.
PubMed: 37091994
DOI: 10.1093/cz/zoac036 -
Frontiers in Endocrinology 2020The androgenic gland (AG)-a unique crustacean endocrine organ that secretes factors such as the insulin-like androgenic gland (IAG) hormone-is a key player in crustacean... (Review)
Review
The androgenic gland (AG)-a unique crustacean endocrine organ that secretes factors such as the insulin-like androgenic gland (IAG) hormone-is a key player in crustacean sex differentiation processes. IAG expression induces masculinization, while the absence of the AG or a deficiency in IAG expression results in feminization. Therefore, by virtue of its universal role as a master regulator of crustacean sexual development, the IAG hormone may be regarded as the sexual "IAG-switch." The switch functions within an endocrine axis governed by neuropeptides secreted from the eyestalks, and interacts downstream with specific insulin receptors at its target organs. In recent years, IAG hormones have been found-and sequenced-in dozens of decapod crustacean species, including crabs, prawns, crayfish and shrimps, bearing different types of reproductive strategies-from gonochorism, through hermaphroditism and intersexuality, to parthenogenesis. The IAG-switch has thus been the focus of efforts to manipulate sex developmental processes in crustaceans. Most sex manipulations were performed using AG ablation or knock-down of the gene in males in order to sex reverse them into "neo-females," or using AG implantation/injecting AG extracts or cells into females to produce "neo-males." These manipulations have highlighted the striking crustacean sexual plasticity in different species and have permitted the manifestation of either maleness or femaleness without altering the genotype of the animals. Furthermore, these sex manipulations have not only facilitated fundamental studies of crustacean sexual mechanisms, but have also enabled the development of the first IAG-switch-based monosex population biotechnologies, primarily for aquaculture but also for pest control. Here, we review the crustacean IAG-switch, a unique crustacean endocrine mechanism, from the early discoveries of the AG and the IAG hormone to recent IAG-switch-based manipulations. Moreover, we discuss this unique early pancrustacean insulin-based sexual differentiation control mechanism in contrast to the extensively studied mechanisms in vertebrates, which are based on sex steroids.
Topics: Animals; Arthropod Proteins; Decapoda; Endocrine System; Insulin; Invertebrate Hormones; Sex Differentiation; Signal Transduction
PubMed: 33013714
DOI: 10.3389/fendo.2020.00651 -
Genome Biology and Evolution Apr 2024Bacteria in the genus Wolbachia have evolved numerous strategies to manipulate arthropod sex, including the conversion of would-be male offspring to asexually...
Bacteria in the genus Wolbachia have evolved numerous strategies to manipulate arthropod sex, including the conversion of would-be male offspring to asexually reproducing females. This so-called "parthenogenesis induction" phenotype can be found in a number of Wolbachia strains that infect arthropods with haplodiploid sex determination systems, including parasitoid wasps. Despite the discovery of microbe-mediated parthenogenesis more than 30 yr ago, the underlying genetic mechanisms have remained elusive. We used a suite of genomic, computational, and molecular tools to identify and characterize two proteins that are uniquely found in parthenogenesis-inducing Wolbachia and have strong signatures of host-associated bacterial effector proteins. These putative parthenogenesis-inducing proteins have structural homology to eukaryotic protein domains including nucleoporins, the key insect sex determining factor Transformer, and a eukaryotic-like serine-threonine kinase with leucine-rich repeats. Furthermore, these proteins significantly impact eukaryotic cell biology in the model Saccharomyces cerevisiae. We suggest that these proteins are parthenogenesis-inducing factors and our results indicate that this would be made possible by a novel mechanism of bacterial-host interaction.
Topics: Male; Animals; Female; Wolbachia; Parthenogenesis; Wasps; Bacterial Proteins; Genomics; Symbiosis
PubMed: 38530785
DOI: 10.1093/gbe/evae036 -
Science Advances Feb 2022The shift from sexual reproduction to parthenogenesis has occurred repeatedly in animals, but how the loss of sex affects genome evolution remains poorly understood. We...
The shift from sexual reproduction to parthenogenesis has occurred repeatedly in animals, but how the loss of sex affects genome evolution remains poorly understood. We generated reference genomes for five independently evolved parthenogenetic species in the stick insect genus and their closest sexual relatives. Using these references and population genomic data, we show that parthenogenesis results in an extreme reduction of heterozygosity and often leads to genetically uniform populations. We also find evidence for less effective positive selection in parthenogenetic species, suggesting that sex is ubiquitous in natural populations because it facilitates fast rates of adaptation. Parthenogenetic species did not show increased transposable element (TE) accumulation, likely because there is little TE activity in the genus. By using replicated sexual-parthenogenetic comparisons, our study reveals how the absence of sex affects genome evolution in natural populations, providing empirical support for the negative consequences of parthenogenesis as predicted by theory.
Topics: Animals; DNA Transposable Elements; Genome, Insect; Insecta; Neoptera; Parthenogenesis; Reproduction
PubMed: 35196080
DOI: 10.1126/sciadv.abg3842 -
International Journal of Molecular... Aug 2021Parthenogenetic embryos have been widely studied as an effective tool related to paternal and maternal imprinting genes and reproductive problems for a long time. In...
Parthenogenetic embryos have been widely studied as an effective tool related to paternal and maternal imprinting genes and reproductive problems for a long time. In this study, we established a parthenogenetic epiblast-like stem cell line through culturing parthenogenetic diploid blastocysts in a chemically defined medium containing activin A and bFGF named paAFSCs. The paAFSCs expressed pluripotent marker genes and germ-layer-related genes, as well as being alkaline-phosphatase-positive, which is similar to epiblast stem cells (EpiSCs). We previously showed that advanced embryonic stem cells (ASCs) represent hypermethylated naive pluripotent embryonic stem cells (ESCs). Here, we converted paAFSCs to ASCs by replacing bFGF with bone morphogenetic protein 4 (BMP4), CHIR99021, and leukemia inhibitory factor (LIF) in a culture medium, and we obtained parthenogenetic advanced stem cells (paASCs). The paASCs showed similar morphology with ESCs and also displayed a stronger developmental potential than paAFSCs in vivo by producing chimaeras. Our study demonstrates that maternal genes could support parthenogenetic EpiSCs derived from blastocysts and also have the potential to convert primed state paAFSCs to naive state paASCs.
Topics: Activins; Animals; Blastocyst; Bone Morphogenetic Protein 4; Cell Culture Techniques; Cell Differentiation; DNA Methylation; Embryo Culture Techniques; Embryonic Stem Cells; Female; Fibroblast Growth Factors; Germ Layers; Leukemia Inhibitory Factor; Mice; Mice, 129 Strain; Mice, Inbred ICR; Mouse Embryonic Stem Cells; Parthenogenesis; Pluripotent Stem Cells
PubMed: 34445681
DOI: 10.3390/ijms22168976 -
Ecology and Evolution Jul 2023Reconstruction of species histories is a central aspect of evolutionary biology. Patterns of genetic variation within and among populations can be leveraged to elucidate...
Reconstruction of species histories is a central aspect of evolutionary biology. Patterns of genetic variation within and among populations can be leveraged to elucidate evolutionary processes and demographic histories. However, interpreting genetic signatures and unraveling the contributing processes can be challenging, in particular for non-model organisms with complex reproductive modes and genome organization. One way forward is the combined consideration of patterns revealed by different molecular markers (nuclear vs. mitochondrial) and types of variants (common vs. rare) that differ in their age, mode, and rate of evolution. Here, we applied this approach to RNAseq data generated for (Archaeognatha), an Alpine jumping bristletail considered parthenogenetic and triploid. We generated de novo transcriptome and mitochondrial assemblies to obtain high-density data to investigate patterns of mitochondrial and common and rare nuclear variation in 17 individuals sampled from all known populations. We find that the different variant types capture distinct aspects of the evolutionary history and discuss the observed patterns in the context of parthenogenesis, polyploidy, and survival during glaciation. This study highlights the potential of different variant types to gain insights into evolutionary scenarios even from challenging but often available data and the suitability of and the genus as a study system for the evolution of sexual strategies and polyploidization during environmental change. We also emphasize the need for further research which will be stimulated and facilitated by these newly generated resources and insights.
PubMed: 37404697
DOI: 10.1002/ece3.10227 -
Current Opinion in Insect Science Apr 2023Endosymbionts are maternally transmitted, and therefore benefit from maximizing female offspring numbers. Parthenogenesis-induction (PI) is the most effective type of... (Review)
Review
Endosymbionts are maternally transmitted, and therefore benefit from maximizing female offspring numbers. Parthenogenesis-induction (PI) is the most effective type of manipulation for transmission, but has solely been detected in haplodiploid species, whereas cytoplasmic incompatibility (CI) is detected frequently across the arthropod phylum, including haplodiploids. This puzzling observation led us to hypothesize that the molecular sex-determination mechanism of the haplodiploid host may be a constraining factor in the ability of endosymbionts to induce parthenogenesis. Recent insights indicate that PI-endosymbionts may be able to directly manipulate sex-determination genes to induce the necessary steps required for PI in haplodiploids. However, sex-determination cascades vary extensively, so PI-induction would require a specialized and host-dependent tool set. Contrastingly, CI-related genes target conserved cell-cycle mechanisms, are located on mobile elements, and spread easily. Finally, endosymbiont-manipulations may have a strong impact on the effectiveness of haplodiploid biocontrol agents, but can also be used to enhance their efficacy.
Topics: Animals; Female; Parthenogenesis; Wolbachia; Arthropods; Sex Determination Processes
PubMed: 36958587
DOI: 10.1016/j.cois.2023.101023 -
Frontiers in Cell and Developmental... 2022The cladoceran crustacean produces only females by parthenogenesis in a healthy population. However, in response to environmental declines such as crowding and lack of... (Review)
Review
The cladoceran crustacean produces only females by parthenogenesis in a healthy population. However, in response to environmental declines such as crowding and lack of foods, it produces eggs destined to become males that are genetically identical to females. During the development of the sexually committed eggs, DM domain-containing transcription factor () orchestrates male trait formation globally both in somatic and gonadal tissues. Recent studies have revealed that expression is tightly controlled at transcriptional, post-transcriptional, and epigenetic levels to avoid sexual ambiguity. In this review, together with basic information on structure and expression, we introduce the multi-layered regulation and discuss how each regulation is interconnected for controlling male development in environmental sex-determining .
PubMed: 35493103
DOI: 10.3389/fcell.2022.881255 -
Nature Communications Nov 2023The formation and consequences of polyploidization in animals with clonal reproduction remain largely unknown. Clade I root-knot nematodes (RKNs), characterized by...
The formation and consequences of polyploidization in animals with clonal reproduction remain largely unknown. Clade I root-knot nematodes (RKNs), characterized by parthenogenesis and allopolyploidy, show a widespread geographical distribution and extensive agricultural destruction. Here, we generated 4 unzipped polyploid RKN genomes and identified a putative novel alternative telomeric element. Then we reconstructed 4 chromosome-level assemblies and resolved their genome structures as AAB for triploid and AABB for tetraploid. The phylogeny of subgenomes revealed polyploid RKN origin patterns as hybridization between haploid and unreduced gametes. We also observed extensive chromosomal fusions and homologous gene expression decrease after polyploidization, which might offset the disadvantages of clonal reproduction and increase fitness in polyploid RKNs. Our results reveal a rare pathway of polyploidization in parthenogenic polyploid animals and provide a large number of high-precision genetic resources that could be used for RKN prevention and control.
Topics: Animals; Polyploidy; Hybridization, Genetic; Triploidy; Germ Cells; Chromosomes; Nematoda
PubMed: 37935661
DOI: 10.1038/s41467-023-42700-w