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Nature Communications Dec 2022Introducing asexual reproduction through seeds - apomixis - into crop species could revolutionize agriculture by allowing F1 hybrids with enhanced yield and stability to...
Introducing asexual reproduction through seeds - apomixis - into crop species could revolutionize agriculture by allowing F1 hybrids with enhanced yield and stability to be clonally propagated. Engineering synthetic apomixis has proven feasible in inbred rice through the inactivation of three genes (MiMe), which results in the conversion of meiosis into mitosis in a line ectopically expressing the BABYBOOM1 (BBM1) parthenogenetic trigger in egg cells. However, only 10-30% of the seeds are clonal. Here, we show that synthetic apomixis can be achieved in an F1 hybrid of rice by inducing MiMe mutations and egg cell expression of BBM1 in a single step. We generate hybrid plants that produce more than 95% of clonal seeds across multiple generations. Clonal apomictic plants maintain the phenotype of the F1 hybrid along successive generations. Our results demonstrate that there is no barrier to almost fully penetrant synthetic apomixis in an important crop species, rendering it compatible with use in agriculture.
Topics: Oryza; Apomixis; Plants; Seeds; Mutation
PubMed: 36575169
DOI: 10.1038/s41467-022-35679-3 -
International Journal of Reproductive... May 2023Parthenogenesis (PG) is a rare phenomenon occurring in humans, and understanding this may help us develop an explanation for such occurrences. Moreover, it may help... (Review)
Review
Parthenogenesis (PG) is a rare phenomenon occurring in humans, and understanding this may help us develop an explanation for such occurrences. Moreover, it may help reveal the cause of idiopathic ovarian teratoma (OT). We aim to explain the occurrence of PG and OT in humans based on a new hypothesis. Previous literature has been searched through relevant scientific websites and international journals on the causes and mechanisms of PG and OT in humans. The previous literature on human PG was sparse and mostly contained case reports. It appears that human PG is not as rare as previously reported but may occur spontaneously, resulting in OT formation. The difference between PG and sexual reproduction is that PG has no embryonic diversity. The biopsied embryonic samples in the PG correspond exclusively to those of the maternal side. Spontaneous PG in humans often degrades or leads to formation of OT. The cause and mechanism of spontaneous PG remain unclear in the available literature. Here, we hypothesized that in some cases the secondary oocyte and first polar body enclosed in the zona pellucida may fuse together to form a single cell that restores the diploid number of chromosomes and initiates cell division to form PG. It may go unnoticed or be represented by the OT. Future studies are recommended to investigate this hypothesis.
PubMed: 37260553
DOI: 10.18502/ijrm.v21i4.13267 -
Comparative Cytogenetics 2021The paper is a third part of the themed issue "Aberrant cytogenetic and reproductive patterns in the evolution of Paraneoptera", prepared by a Russian-Bulgarian research... (Review)
Review
The paper is a third part of the themed issue "Aberrant cytogenetic and reproductive patterns in the evolution of Paraneoptera", prepared by a Russian-Bulgarian research team on the basis of long-term collaborative studies. This chapter reviews different peculiar aberrations in the ontogenesis of Paraneoptera, such as the appearance of the quiescent apodal and/or arostrate instars, exuviatrial, pupillarial and pseudopupillarial development, cyclic parthenogenesis, etc. The material and methods, terminology and the nomenclature of the used taxonomic names are listed in the first chapter of the issue (Gavrilov-Zimin et al. 2021).
PubMed: 34484615
DOI: 10.3897/compcytogen.v15.i3.70362 -
Brazilian Journal of Biology = Revista... 2022Termites are known as social insects worldwide. Presently in China 473 species, 44 genera and 4 families of termites have been reported. Of them, 111 Reticulitermes... (Review)
Review
Termites are known as social insects worldwide. Presently in China 473 species, 44 genera and 4 families of termites have been reported. Of them, 111 Reticulitermes species are widely spread in different zones of China. The dispersion flight season of these Chinese Reticulitermes species are usually started from February to June, but in some regions different species are distributed, sharing their boundaries and having overlapping flight seasons. These reasons become important sources of hybridization between two different heterospecific populations of termites. It was confirmed that the fertilized eggs and unfertilized eggs of some Reticulitermes termites have the capacity of cleavage. While the unfertilized eggs of R. aculabialis, R. chinensis and R. labralis cleaved normally and the only R. aculabialis unfertilized eggs develop in embryos. While, the R. flaviceps and R. chinensis were observed with their abnormal embryonic development, and not hatching of eggs parthenogenetically. They were reported more threatening to Chinese resources as they propagate with parthenogenesis, hybridization and sexual reproduction. Eggshell and macrophiles of eggs play important roles in species identification and control. Although, they are severe pests and cause a wide range of damages to wooden structures and products in homes, buildings, building materials, trees, crops, and forests in China's Mainland.
Topics: Animals; China; Cockroaches; Isoptera; Reproduction
PubMed: 35319619
DOI: 10.1590/1519-6984.256354 -
Plant Reproduction Dec 2021In plants, small RNAs have been recognized as key genetic and epigenetic regulators of development. Small RNAs are usually 20 to 30 nucleotides in length and they... (Review)
Review
In plants, small RNAs have been recognized as key genetic and epigenetic regulators of development. Small RNAs are usually 20 to 30 nucleotides in length and they control, in a sequence specific manner, the transcriptional or post-transcriptional expression of genes. In this review, we present a comprehensive overview of the most recent findings about the function of small RNAs in ovule development, including megasporogenesis and megagametogenesis, both in sexual and apomictic plants. We discuss recent studies on the role of miRNAs, siRNAs and trans-acting RNAs (ta-siRNAs) in early female germline differentiation. The mechanistic complexity and unique regulatory features are reviewed, and possible directions for future research are provided.
Topics: Apomixis; Gene Expression Regulation, Plant; MicroRNAs; Ovule
PubMed: 34142243
DOI: 10.1007/s00497-021-00421-4 -
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 -
Proceedings of the National Academy of... Mar 2022In mammals, a new life starts with the fusion of an oocyte and asperm cell. Parthenogenesis, a way of generating offspring solelyfrom female gametes, is limited because...
In mammals, a new life starts with the fusion of an oocyte and asperm cell. Parthenogenesis, a way of generating offspring solelyfrom female gametes, is limited because of problems arising fromgenomic imprinting. Here, we report live mammalian offspringderived from single unfertilized oocytes, which was achieved by tar-geted DNA methylation rewriting of seven imprinting control regions.Oocyte coinjection of catalytically inactive Cas9 (dCas9)-Dnmt3a ordCpf1-Tet1 messenger RNA (mRNA) with single-guide RNAs (sgRNAs)targeting specific regions induced de novo methylation or demethyla-tion, respectively, of the targeted region. Following parthenogeneticactivation, these edited regions showed maintenance of methylationas naturally established regions during early preimplantation develop-ment. The transfer of modified parthenogenetic embryos into fostermothers resulted in significantly extended development andfinally inthe generation of viable full-term offspring. These data demonstratethat parthenogenesis can be achieved by targeted epigenetic rewrit-ing of multiple critical imprinting control regions.
Topics: Animals; DNA Methylation; Genomic Imprinting; Mammals; Oocytes; Parthenogenesis
PubMed: 35254875
DOI: 10.1073/pnas.2115248119 -
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 -
Methods in Molecular Biology (Clifton,... 2021In this chapter, we present a list of species (and few interspecific hybrids) where haploids and/or doubled haploids have been published, including the method by which...
In this chapter, we present a list of species (and few interspecific hybrids) where haploids and/or doubled haploids have been published, including the method by which they were obtained and the corresponding references. This list is an update of the compilation work of Maluszynski et al. published in 2003, including new species for which protocols were not available at that time, and also novel methodologies developed during these years. The list includes 383 different backgrounds. In this book, we present full protocols to produce DHs in 43 of the species included in this list. In addition, this book includes a chapter for one species not included in the list. This makes a total of 384 species where haploids and/or DHs have been reported up to date.
Topics: Crops, Agricultural; Haploidy; Parthenogenesis; Plant Breeding; Pollen
PubMed: 34270025
DOI: 10.1007/978-1-0716-1315-3_3