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Annals of Botany Jun 2024Rubus ser. Glandulosi provides a unique model of geographical parthenogenesis on a homoploid (2n = 4x) level. We aim to characterize evolutionary and...
BACKGROUND AND AIMS
Rubus ser. Glandulosi provides a unique model of geographical parthenogenesis on a homoploid (2n = 4x) level. We aim to characterize evolutionary and phylogeographical patterns in this taxon and shed light on the geographical differentiation of apomicts and sexuals. Ultimately, we aim to evaluate the importance of phylogeography in the formation of geographical parthenogenesis.
METHODS
Rubus ser. Glandulosi was sampled across its Eurasian range together with other co-occurring Rubus taxa (587 individuals in total). Double-digest restriction site-associated DNA sequencing (ddRADseq) and modelling of suitable climate were used for evolutionary inferences.
KEY RESULTS
Six ancestral species were identified that contributed to the contemporary gene pool of R. ser. Glandulosi. Sexuals were introgressed from Rubus dolichocarpus and Rubus moschus in West Asia and from Rubus ulmifolius agg., Rubus canescens and Rubus incanescens in Europe, whereas apomicts were characterized by alleles of Rubus subsect. Rubus. Gene flow between sexuals and apomicts was also detected, as was occasional hybridization with other taxa.
CONCLUSIONS
We hypothesize that sexuals survived the last glacial period in several large southern refugia, whereas apomicts were mostly restricted to southern France, whence they quickly recolonized Central and Western Europe. The secondary contact of sexuals and apomicts was probably the principal factor that established geographical parthenogenesis in R. ser. Glandulosi. Sexual populations are not impoverished in genetic diversity along their borderline with apomicts, and maladaptive population genetic processes probably did not shape the geographical patterns.
Topics: Phylogeography; Europe; Rosaceae; Gene Flow; Biological Evolution; Apomixis; Asia; Parthenogenesis; Genetic Variation; Phylogeny
PubMed: 38549558
DOI: 10.1093/aob/mcae050 -
Molecular and Cellular Endocrinology Jun 2024Both male and female reproductive functions are impacted by altered gonadotrophin secretion and action, which may also influence the development of endocrine tumours. To...
Both male and female reproductive functions are impacted by altered gonadotrophin secretion and action, which may also influence the development of endocrine tumours. To ascertain if chronic hypersecretion of human chorionic gonadotropin (hCG) contributes to the development of gonadal tumours, double transgenic (TG) mice that overexpress hCGα- and β-subunits were analysed. By the age of two months, ovarian tumours with characteristics of teratomas developed with 100% penetrance. Teratomas were also seen in wild-type ovaries orthotopically transplanted into TG mice, demonstrating an endocrine/paracrine mechanism for the hCG-induced ovarian tumorigenesis. Both in vitro and in vivo experiments showed oocyte parthenogenetic activation in TG females. In addition, ovaries showed reduced ovulatory gene expression, inhibited ERK1/2 phosphorylation, and impaired cumulus cell expansion. Hence, persistently high endocrine hCG activity causes parthenogenetic activation and development of ovarian teratomas, along with altered follicle development and impaired ERK1/2 signalling, offering a novel mechanism associated with the molecular pathogenesis of ovarian teratomas.
Topics: Mice; Animals; Male; Female; Humans; Infant; Mice, Transgenic; Chorionic Gonadotropin; Oocytes; Ovarian Neoplasms; Teratoma
PubMed: 38537882
DOI: 10.1016/j.mce.2024.112214 -
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 -
Evolution; International Journal of... May 2024Reproduction is a key feature of all organisms, yet the way in which it is achieved varies greatly across the tree of life. One striking example of this variation is the...
Reproduction is a key feature of all organisms, yet the way in which it is achieved varies greatly across the tree of life. One striking example of this variation is the stick insect genus Bacillus, in which five different reproductive modes have been described: sex, facultative and obligate parthenogenesis, and two highly unusual reproductive modes: hybridogenesis and androgenesis. Under hybridogenesis, the entire genome from the paternal species is eliminated and replaced each generation by mating with the corresponding species. Under androgenesis, an egg is fertilized, but the developing diploid offspring bear two paternal genomes and no maternal genome, as a consequence of unknown mechanisms. Here, we reevaluate the previous descriptions of Bacillus lineages and the proposed F1 hybrid ancestries of the hybridogenetic and obligately parthenogenetic lineages (based on allozymes and karyotypes) from Sicily, where all these reproductive modes are found. We generate a chromosome-level genome assembly for a facultative parthenogenetic species (B. rossius) and combine extensive field sampling with RADseq and mtDNA data. We identify and genetically corroborate all previously described species and confirm the ancestry of hybrid lineages. All hybrid lineages have fully retained their F1 hybrid constitution throughout the genome, indicating that the elimination of the paternal genome in hybridogens is always complete and that obligate parthenogenesis in Bacillus hybrid species is not associated with an erosion of heterozygosity as known in other hybrid asexuals. Our results provide a stepping stone toward understanding the transitions between reproductive modes and the proximate mechanisms of genome elimination.
Topics: Animals; Parthenogenesis; Male; Insecta; Female; Biological Evolution; Genome, Insect; Reproduction; Hybridization, Genetic; DNA, Mitochondrial
PubMed: 38501929
DOI: 10.1093/evolut/qpae045 -
Annals of Botany Jun 2024The predominance of sex in eukaryotes, despite the high costs of meiosis and mating, remains an evolutionary enigma. Many theories have been proposed, none of them being... (Review)
Review
BACKGROUND
The predominance of sex in eukaryotes, despite the high costs of meiosis and mating, remains an evolutionary enigma. Many theories have been proposed, none of them being conclusive on its own, and they are, in part, not well applicable to land plants. Sexual reproduction is obligate in embryophytes for the great majority of species.
SCOPE
This review compares the main forms of sexual and asexual reproduction in ferns and angiosperms, based on the generation cycling of sporophyte and gametophyte (leaving vegetative propagation aside). The benefits of sexual reproduction for maintenance of genomic integrity in comparison to asexuality are discussed in the light of developmental, evolutionary, genetic and phylogenetic studies.
CONCLUSIONS
Asexual reproduction represents modifications of the sexual pathway, with various forms of facultative sexuality. For sexual land plants, meiosis provides direct DNA repair mechanisms for oxidative damage in reproductive tissues. The ploidy alternations of meiosis-syngamy cycles and prolonged multicellular stages in the haploid phase in the gametophytes provide a high efficiency of purifying selection against recessive deleterious mutations. Asexual lineages might buffer effects of such mutations via polyploidy and can purge the mutational load via facultative sexuality. The role of organelle-nuclear genome compatibility for maintenance of genome integrity is not well understood. In plants in general, the costs of mating are low because of predominant hermaphroditism. Phylogenetic patterns in the archaeplastid clade suggest that high frequencies of sexuality in land plants are concomitant with a stepwise increase of intrinsic and extrinsic stress factors. Furthermore, expansion of genome size in land plants would increase the potential mutational load. Sexual reproduction appears to be essential for keeping long-term genomic integrity, and only rare combinations of extrinsic and intrinsic factors allow for shifts to asexuality.
Topics: Apomixis; Magnoliopsida; Reproduction, Asexual; Biological Evolution; Ferns; Reproduction; Phylogeny; Meiosis; Plants
PubMed: 38497809
DOI: 10.1093/aob/mcae044 -
International Journal For Parasitology Jun 2024There are several species of gymnophallid digeneans in the genus Parvatrema that are unique in developing metacercariae that reproduce by parthenogenesis in the second... (Review)
Review
There are several species of gymnophallid digeneans in the genus Parvatrema that are unique in developing metacercariae that reproduce by parthenogenesis in the second intermediate host. Transmission of these digeneans takes place in coastal ecosystems of the North Pacific and North Atlantic seas. The first intermediate hosts are bivalves, the second ones are gastropods, and the definitive hosts are migratory birds. We integrated data accumulated over 25 years of research and differentiated a complex of five closely related species. They differ in the molluscan second intermediate hosts, distribution ranges, and life cycles patterns. The type I life cycle includes two generations of parthenogenetic metacercariae, followed by development of metacercariae which are invasive for the definitive host. In the type II life cycle, the number of generations of parthenogenetic metacercariae is unlimited, and they can also produce cercariae. These cercariae emerge into the environment and can infect new individuals of the second intermediate host. We conclude that the type I life cycle is a derived option that has evolved as a better fit to transmission in the unstable conditions in the intertidal zone. Another evolutionary trend in Parvatrema is transition from inhabiting the extrapallial space of the gastropod second intermediate host to endoparasitism in its mantle and internal organs. rDNA sequence analysis highlighted that Parvatrema spp. with parthenogenetic metacercariae form a monophyletic clade and suggested the Pacific origin of the group, with two transfers to the North Atlantic and colonisation of new second intermediate host species. Apparently the group formed in the late Pliocene-Pleistocene and diversified as a result of recurrent isolation in inshore refugia during glacial periods. We argue that parthenogenetic metacercariae in Parvatrema may serve as a model for early digenean evolution, demonstrating the first steps of adopting the molluscan first intermediate host and becoming tissue parasites.
Topics: Animals; Trematoda; Host Specificity; Metacercariae; Trematode Infections; Phylogeny; Parthenogenesis; Life Cycle Stages; Birds; Biodiversity; Bivalvia
PubMed: 38452965
DOI: 10.1016/j.ijpara.2024.02.002 -
Cell Proliferation Mar 2024NIMA-related kinase 2 (NEK2) is a serine/threonine protein kinase that regulates mitosis and plays pivotal roles in cell cycle regulation and DNA damage repair. However,...
NIMA-related kinase 2 (NEK2) is a serine/threonine protein kinase that regulates mitosis and plays pivotal roles in cell cycle regulation and DNA damage repair. However, its function in porcine embryonic development is unknown. In this study, we used an NEK2-specific inhibitor, JH295 (JH), to investigate the role of NEK2 in embryonic development and the underlying regulatory mechanisms. Inhibition of NEK2 after parthenogenesis activation or in vitro fertilization significantly reduced the rates of cleavage and blastocyst formation, the numbers of trophectoderm and total cells and the cellular survival rate compared with the control condition. NEK2 inhibition delayed cell cycle progression at all stages from interphase to cytokinesis during the first mitotic division; it caused abnormal nuclear morphology in two- and four-cell stage embryos. Additionally, NEK2 inhibition significantly increased DNA damage and apoptosis, and it altered the expression levels of DNA damage repair- and apoptosis-related genes. Intriguingly, NEK2 inhibition downregulated the expression of β-catenin and its downstream target genes. To validate the relationship between Wnt/β-catenin signalling and NEK2 during porcine embryonic development, we cultured porcine embryos in JH-treated medium with or without CHIR99021, a Wnt activator. CHIR99021 co-treatment strongly restored the developmental parameters reduced by NEK2 inhibition to control levels. Our findings suggest that NEK2 plays an essential role in porcine embryonic development by regulating DNA damage repair and normal mitotic division via the Wnt/β-catenin signalling pathway.
PubMed: 38426218
DOI: 10.1111/cpr.13626 -
Scientific Reports Feb 2024Ricinus communis is one of the most important oilseed plants with many medicinal and industrial applications. Variation in 30 genotypes of castor bean collected from...
Ricinus communis is one of the most important oilseed plants with many medicinal and industrial applications. Variation in 30 genotypes of castor bean collected from different regions of the world was evaluated for two consecutive years and the difference in seed production with two different reproductive modes (including apomixis and open-pollination) was compared based on yield components, agronomic traits, and phytochemical properties. Results of data analysis demonstrated that castor bean has the ability for a wide range of apomixis for seed production and the highest percentages of apomixis ability in the first and second years were 86.3% and 92.31%, respectively. Apomixis ability had a high positive correlation with yield components, seed oil content, and the amount of leaf rutin. Two genotypes from Brazil and Syria revealed the highest phenolic content in the first and second years, respectively. In addition, the Afghanistan genotype in two modes of apomixis and open-pollination in the first year and the Syria and Yazd genotypes in apomixis and open-pollination modes, respectively, in the second year showed the highest content of seed fatty acids. It is possible to maintain superior genotypes of castor bean in terms of phytochemical traits, yield, and oil quality through apomixis reproduction.
Topics: Ricinus communis; Apomixis; Seeds; Fatty Acids; Phytochemicals
PubMed: 38424457
DOI: 10.1038/s41598-024-53700-1 -
Journal of Experimental Zoology. Part... Jun 2024Hybrid parthenogenetic animals are an exceptionally interesting model for studying the mechanisms and evolution of sexual and asexual reproduction. A diploid...
Hybrid parthenogenetic animals are an exceptionally interesting model for studying the mechanisms and evolution of sexual and asexual reproduction. A diploid parthenogenetic lizard Darevskia unisexualis is a result of an ancestral cross between a maternal species Darevskia raddei nairensis and a paternal species Darevskia valentini and presents a unique opportunity for a cytogenetic and computational analysis of a hybrid karyotype. Our previous results demonstrated a significant divergence between the pericentromeric DNA sequences of the parental Darevskia species; however, an in-depth comparative study of their pericentromeres is still lacking. Here, using target sequencing of microdissected pericentromeric regions, we reveal and compare the repertoires of the pericentromeric tandem repeats of the parental Darevskia lizards. We found species-specific sequences of the major pericentromeric tandem repeat CLsat, which allowed computational prediction and experimental validation of fluorescent DNA probes discriminating parental chromosomes within the hybrid karyotype of D. unisexualis. Moreover, we have implemented a generalizable computational method, based on the optimization of the Levenshtein distance between tandem repeat monomers, for finding species-specific fluorescent probes for pericentromere staining. In total, we anticipate that our comparative analysis of Darevskia pericentromeric repeats, the species-specific fluorescent probes that we found and the pipeline that we developed will form a basis for the future detailed cytogenomic studies of a wide range of natural and laboratory hybrids.
Topics: Animals; Lizards; DNA, Satellite; Parthenogenesis; Hybridization, Genetic; Karyotype; Species Specificity
PubMed: 38407543
DOI: 10.1002/jez.b.23244 -
The New Phytologist May 2024Asexual organisms often differ in their geographic distributions from their sexual relatives. This phenomenon, termed geographic parthenogenesis, has long been known,...
Asexual organisms often differ in their geographic distributions from their sexual relatives. This phenomenon, termed geographic parthenogenesis, has long been known, but the underlying factors behind its diverse patterns have been under dispute. Particularly problematic is an association between asexuality and polyploidy in most taxa. Here, we present a new system of geographic parthenogenesis on the tetraploid level, promising new insights into this complex topic. We used flow cytometric seed screen and microsatellite genotyping to characterise the patterns of distribution of sexuals and apomicts and genotypic distributions in Rubus ser. Glandulosi across its range. Ecological modelling and local-scale vegetation and soil analyses were used to test for niche differentiation between the reproductive groups. Apomicts were detected only in North-western Europe, sexuals in the rest of the range in Europe and West Asia, with a sharp borderline stretched across Central Europe. Despite that, we found no significant differences in ecological niches. Genotypic richness distributions suggested independence of the reproductive groups and a secondary contact. We argue that unless a niche differentiation (resulting from polyploidy and/or hybridity) evolves, the main factors behind the patterns of geographic parthenogenesis in plants are phylogeographic history and neutral microevolutionary processes, such as clonal turnover.
Topics: Rubus; Parthenogenesis; Ploidies; Apomixis; Polyploidy
PubMed: 38407427
DOI: 10.1111/nph.19618