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Genes Jul 2020Apomixis (agamospermy) is asexual reproduction by seed. In angiosperms it represents an easy byway of life cycle renewal through gamete-like cells that give rise to... (Review)
Review
Apomixis (agamospermy) is asexual reproduction by seed. In angiosperms it represents an easy byway of life cycle renewal through gamete-like cells that give rise to maternal embryos without ploidy reduction (meiosis) and ploidy restitution (syngamy). The origin of apomixis still represents an unsolved problem, as it may be either evolved from sex or the other way around. This review deals with a reappraisal of the origin of apomixis in order to deepen knowledge on such asexual mode of reproduction which seems mainly lacking in the most basal angiosperm orders (i.e., Amborellales, Nymphaeales and Austrobaileyales, also known as ANA-grade), while it clearly occurs in different forms and variants in many unrelated families of monocots and eudicots. Overall findings strengthen the hypothesis that apomixis as a whole may have evolved multiple times in angiosperm evolution following different developmental pathways deviating to different extents from sexuality. Recent developments on the genetic control of apomixis in model species are also presented and adequately discussed in order to shed additional light on the antagonist theories of gain- and loss-of-function over sexuality.
Topics: Apomixis; Evolution, Molecular; Gene Expression Regulation, Developmental; Gene Expression Regulation, Plant; Magnoliopsida; Plant Proteins; Seeds
PubMed: 32731368
DOI: 10.3390/genes11080859 -
Genetics Sep 2022Eurasian brine shrimp (genus Artemia) have closely related sexual and asexual lineages of parthenogenetic females, which produce rare males at low frequencies. Although...
Eurasian brine shrimp (genus Artemia) have closely related sexual and asexual lineages of parthenogenetic females, which produce rare males at low frequencies. Although they are known to have ZW chromosomes, these are not well characterized, and it is unclear whether they are shared across the clade. Furthermore, the underlying genetic architecture of the transmission of asexuality, which can occur when rare males mate with closely related sexual females, is not well understood. We produced a chromosome-level assembly for the sexual Eurasian species Artemia sinica and characterized in detail the pair of sex chromosomes of this species. We combined this new assembly with short-read genomic data for the sexual species Artemia sp. Kazakhstan and several asexual lineages of Artemia parthenogenetica, allowing us to perform an in-depth characterization of sex-chromosome evolution across the genus. We identified a small differentiated region of the ZW pair that is shared by all sexual and asexual lineages, supporting the shared ancestry of the sex chromosomes. We also inferred that recombination suppression has spread to larger sections of the chromosome independently in the American and Eurasian lineages. Finally, we took advantage of a rare male, which we backcrossed to sexual females, to explore the genetic basis of asexuality. Our results suggest that parthenogenesis is likely partly controlled by a locus on the Z chromosome, highlighting the interplay between sex determination and asexuality.
Topics: Animals; Artemia; Female; Genome; Male; Parthenogenesis; Reproduction; Sex Chromosomes
PubMed: 35977389
DOI: 10.1093/genetics/iyac123 -
Frontiers in Plant Science 2023
PubMed: 36866376
DOI: 10.3389/fpls.2023.1145208 -
Animals : An Open Access Journal From... Apr 2021This study aimed to examine the effects of treatment with glucuronic acid (GA) and N-acetyl-D-glucosamine (AG), which are components of hyaluronic acid (HA), during...
Effect of D-Glucuronic Acid and N-acetyl-D-Glucosamine Treatment during In Vitro Maturation on Embryonic Development after Parthenogenesis and Somatic Cell Nuclear Transfer in Pigs.
This study aimed to examine the effects of treatment with glucuronic acid (GA) and N-acetyl-D-glucosamine (AG), which are components of hyaluronic acid (HA), during porcine oocyte in vitro maturation (IVM). We measured the diameter of the oocyte, the thickness of the perivitelline space (PVS), the reactive oxygen species (ROS) level, and the expression of cumulus cell expansion and ROS-related genes and examined the cortical granule (CG) reaction of oocytes. The addition of 0.05 mM GA and 0.05 mM AG during the first 22 h of oocyte IVM significantly increased oocyte diameter and PVS size compared with the control (non-treatment). The addition of GA and AG reduced the intra-oocyte ROS content and improved the CG of the oocyte. GA and AG treatment increased the expression of and in cumulus cells and and in oocytes. In both the chemically defined and the complex medium (Medium-199 + porcine follicular fluid), oocytes derived from the GA and AG treatments presented significantly higher blastocyst rates than the control after parthenogenesis (PA) and somatic cell nuclear transfer (SCNT). In conclusion, the addition of GA and AG during IVM in pig oocytes has beneficial effects on oocyte IVM and early embryonic development after PA and SCNT.
PubMed: 33917537
DOI: 10.3390/ani11041034 -
Journal of Insect Physiology Jul 2021Clonal transgenic silkworms are useful for the functional analysis of insect genes and for the production of recombinant proteins. Such silkworms have previously been...
Clonal transgenic silkworms are useful for the functional analysis of insect genes and for the production of recombinant proteins. Such silkworms have previously been created using an existing ameiotic parthenogenetic strain. However, the process was labor intensive, and the efficiency of producing transgenic silkworms was very low. To overcome this issue, we developed a more convenient and efficient method by breeding non-diapausing parthenogenetic strains. The strains produced non-diapausing eggs only when the embryogenesis of the parent eggs was performed at low temperatures, which could then be used for injecting vector plasmids. This demonstrated that transgenic silkworms could be produced with greater ease and efficiency. To breed the strains, we crossed the existing parthenogenetic strains with bivoltine strains and made F1 and F2 from each cross. Then we selected the silkworms whose eggs have a high ability of parthenogenesis and became non-diapausing. We also demonstrated that the germplasm could be cryopreserved in liquid nitrogen. Thus, this method increases the efficiency and ease of using genetically engineered silkworms to analyze gene function and produce recombinant proteins, potentially impacting various industries.
Topics: Animals; Animals, Genetically Modified; Bombyx; Cold Temperature; Cryopreservation; Diapause; Embryonic Development; Genes, Insect; Genetic Engineering; Parthenogenesis
PubMed: 34097982
DOI: 10.1016/j.jinsphys.2021.104265 -
Plants (Basel, Switzerland) May 2021The gene flow mediated by unreduced gametes between diploid and tetraploid plants of the complex is pivotal for alfalfa breeding. Sexually tetraploidized hybrids could... (Review)
Review
The gene flow mediated by unreduced gametes between diploid and tetraploid plants of the complex is pivotal for alfalfa breeding. Sexually tetraploidized hybrids could represent the best way to exploit progressive heterosis simultaneously derived from gene diversity, heterozygosity, and polyploidy. Moreover, unreduced gametes combined with parthenogenesis (i.e., apomixis) would enable the cloning of plants through seeds, providing a unique opportunity for the selection of superior genotypes with permanently fixed heterosis. This reproductive strategy has never been detected in the genus , but features of apomixis, such as restitutional apomeiosis and haploid parthenogenesis, have been reported. By means of an original case study, we demonstrated that sexually tetraploidized plants maintain apomeiosis, but this trait is developmentally independent from parthenogenesis. Alfalfa meiotic mutants producing unreduced egg cells revealed a null or very low capacity for parthenogenesis. The overall achievements reached so far are reviewed and discussed along with the efforts and strategies made for exploiting reproductive mutants that express apomictic elements in alfalfa breeding programs. Although several studies have investigated the cytological mechanisms responsible for 2 gamete formation and the inheritance of this trait, only a very small number of molecular markers and candidate genes putatively linked to unreduced gamete formation have been identified. Furthermore, this scenario has remained almost unchanged over the last two decades. Here, we propose a reverse genetics approach, by exploiting the genomic and transcriptomic resources available in alfalfa. Through a comparison with 9 proteins belonging to known for their involvement in 2 gamete production, we identified 47 orthologous genes and evaluated their expression in several tissues, paving the way for novel candidate gene characterization studies. An overall view on strategies suitable to fill the gap between well-established meiotic mutants and next-generation genomic resources is presented and discussed.
PubMed: 34067689
DOI: 10.3390/plants10050999 -
Annual Review of Microbiology Sep 2023Among endosymbiotic bacteria living within eukaryotic cells, is exceptionally widespread, particularly in arthropods. Inherited through the female germline, it has... (Review)
Review
Among endosymbiotic bacteria living within eukaryotic cells, is exceptionally widespread, particularly in arthropods. Inherited through the female germline, it has evolved ways to increase the fraction of bacterially infected offspring by inducing parthenogenesis, feminization, male killing, or, most commonly, cytoplasmic incompatibility (CI). In CI, infection of males causes embryonic lethality unless they mate with similarly infected females, creating a relative reproductive advantage for infected females. A set of related bicistronic operons encodes the CI-inducing factors. The downstream gene encodes a deubiquitylase or nuclease and is responsible for CI induction by males, while the upstream product when expressed in females binds its sperm-introduced cognate partner and rescues viability. Both toxin-antidote and host-modification mechanisms have been proposed to explain CI. Interestingly, male killing by either or endosymbionts involves deubiquitylases as well. Interference with the host ubiquitin system may therefore be a common theme among endosymbiont-mediated reproductive alterations.
Topics: Female; Male; Humans; Wolbachia; Semen; Reproduction; Cytoplasm; Molecular Biology; Symbiosis
PubMed: 37285552
DOI: 10.1146/annurev-micro-041020-024616 -
Development (Cambridge, England) Apr 2022Obligate parthenogenesis evolved in reptiles convergently several times, mainly through interspecific hybridization. The obligate parthenogenetic complexes typically...
Obligate parthenogenesis evolved in reptiles convergently several times, mainly through interspecific hybridization. The obligate parthenogenetic complexes typically include both diploid and triploid lineages. Offspring of parthenogenetic hybrids are genetic copies of their mother; however, the cellular mechanism enabling the production of unreduced cells is largely unknown. Here, we show that oocytes go through meiosis in three widespread, or even strongly invasive, obligate parthenogenetic complexes of geckos, namely in diploid and triploid Lepidodactylus lugubris, and triploid Hemiphyllodactylus typus and Heteronotia binoei. In all four lineages, the majority of oocytes enter the pachytene at the original ploidy level, but their chromosomes cannot pair properly and instead form univalents, bivalents and multivalents. Unreduced eggs with clonally inherited genomes are formed from germ cells that had undergone premeiotic endoreplication, in which appropriate segregation is ensured by the formation of bivalents made from copies of identical chromosomes. We conclude that the induction of premeiotic endoreplication in reptiles was independently co-opted at least four times as an essential component of parthenogenetic reproduction and that this mechanism enables the emergence of fertile polyploid lineages within parthenogenetic complexes.
Topics: Animals; Diploidy; Endoreduplication; Lizards; Parthenogenesis; Triploidy
PubMed: 35388415
DOI: 10.1242/dev.200345 -
Evolution; International Journal of... Jun 2021Although temporally changing environments generally favor sex and recombination, the effects of spatial environmental heterogeneity have been less explored. In this...
Although temporally changing environments generally favor sex and recombination, the effects of spatial environmental heterogeneity have been less explored. In this article, we use a classical model of adaptation along with an environmental gradient to study the selective forces acting on reproductive mode evolution in the central and marginal parts of the distribution range of a species. The model considers a polygenic trait under stabilizing selection (the optimal trait value changing across space) and includes a demographic component imposing range limits. The results show that in the central part of the range (where populations are well adapted), recombination tends to increase the mean fitness of offspring in regimes where drift is sufficiently strong (generating a benefit for sex), while it has the opposite effect when the effect of drift stays negligible. However, these effects remain weak and are easily overwhelmed by slight intrinsic fitness differences between sexuals and asexuals. In agreement with previous results, asexuality may be favored in marginal populations, as it can preserve adaptation to extreme conditions. However, a substantial advantage of asexuality is possible only in conditions maintaining a strong maladaptation of sexuals at range limits (high effective environmental gradient, weak selection at loci coding for the trait).
Topics: Adaptation, Biological; Biological Evolution; Environment; Genetic Drift; Genetic Fitness; Models, Genetic; Reproduction; Reproduction, Asexual; Sex
PubMed: 33901319
DOI: 10.1111/evo.14237 -
Journal of Evolutionary Biology Jul 2021Many sexual-asexual complexes show a distinct pattern where the asexuals have larger and more northerly ranges than closely related sexuals. A prime candidate to explain...
Many sexual-asexual complexes show a distinct pattern where the asexuals have larger and more northerly ranges than closely related sexuals. A prime candidate to explain this so-called "geographical parthenogenesis" is ecological niche divergence between the sexuals and asexuals. Modern niche modelling techniques allow testing niche divergence by directly comparing the niches of sexuals and asexuals. In this study, I use such techniques to perform range-wide tests of whether nine bioclimatic variables, including annual mean temperature and annual precipitation, contribute to geographical parthenogenesis in two dandelion taxa: Taraxacum section Ruderalia and Taraxacum section Erythrosperma, which are both comprised of sexual diploids and asexual triploids. For both sections, I found evidence of niche divergence, though the exact nature of this divergence was different for the two sections. In section Ruderalia, the sexuals preferred warmer and wetter conditions, whereas in section Erythrosperma, the sexuals preferred dryer conditions. Using Species Distribution Modelling, consistent differences between the sexuals and asexuals were found when looking at the niche determinants: the variables that are most important for modelling the distribution. Furthermore, and in contrast with theoretical expectations that predict that the sexuals should have a wider niche, in section Erythrosperma the asexuals were found to have a wider niche than the sexuals. In conclusion, differences in niche optima, niche determinants, and niche width all contribute to the pattern of geographical parthenogenesis of these two dandelion taxa. However, the results also indicate that the exact causation of geographical parthenogenesis is not uniform across taxa.
Topics: Diploidy; Ecosystem; Geography; Parthenogenesis; Taraxacum
PubMed: 33955626
DOI: 10.1111/jeb.13794