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1.
Braz. j. biol ; 84: e256354, 2024.
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1364518

RESUMO

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.


Os cupins são conhecidos como insetos sociais em todo o mundo. Atualmente na China foram relatadas 473 espécies, 44 gêneros e 4 famílias de cupins. Destas, 111 espécies de Reticulitermes estão amplamente distribuídas em diferentes zonas da China. A temporada de voo de dispersão dessas espécies chinesas de Reticulitermes geralmente começa de fevereiro a junho, mas em algumas regiões diferentes espécies são distribuídas, compartilhando seus limites e tendo temporadas de voo sobrepostas. Essas razões tornam-se importantes fontes de hibridização entre duas populações heteroespecíficas de cupins. Foi confirmado que os ovos fertilizados e não fertilizados de alguns cupins Reticulitermes possuem capacidade de clivagem. Já os ovos não fertilizados de R. aculabialis, R. chinensis e R. labralis clivaram normalmente, e os únicos ovos não fertilizados de R. aculabialis se desenvolvem em embriões. R. flaviceps e R. chinensis foram observados com desenvolvimento embrionário anormal, e não eclosão de ovos por partenogênese. Eles foram relatados como mais ameaçadores para os recursos chineses à medida que se propagam com partenogênese, hibridização e reprodução sexual. Casca de ovo e macrófilos de ovos desempenham papéis importantes na identificação e controle de espécies, embora sejam pragas graves e causem uma ampla gama de danos a estruturas e produtos de madeira em residências, edifícios, materiais de construção, árvores, plantações e florestas na China continental.


Assuntos
Animais , Partenogênese , Reprodução , Isópteros/crescimento & desenvolvimento , China , Hibridização Genética
2.
Evolution ; 77(1): 1-12, 2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-36622707

RESUMO

In some asexual species, parthenogenetic females occasionally produce males, which may strongly affect the evolution and maintenance of asexuality if they cross with related sexuals and transmit genes causing asexuality to their offspring ("contagious parthenogenesis"). How these males arise in the first place has remained enigmatic, especially in species with sex chromosomes. Here, we test the hypothesis that rare, asexually produced males of the crustacean Artemia parthenogenetica are produced by recombination between the Z and W sex chromosomes during non-clonal parthenogenesis, resulting in ZZ males through loss of heterozygosity at the sex determination locus. We used RAD-sequencing to compare asexual mothers with their male and female offspring. Markers on several sex-chromosome scaffolds indeed lost heterozygosity in all male but no female offspring, suggesting that they correspond to the sex-determining region. Other sex-chromosome scaffolds lost heterozygosity in only a part of the male offspring, consistent with recombination occurring at a variable location. Alternative hypotheses for the production of these males (such as partial or total hemizygosity of the Z) could be excluded. Rare males are thus produced because recombination is not entirely suppressed during parthenogenesis in A. parthenogenetica. This finding may contribute to explaining the maintenance of recombination in these asexuals.


Assuntos
Artemia , Partenogênese , Feminino , Animais , Masculino , Artemia/genética , Partenogênese/genética , Heterozigoto , Recombinação Genética , Reprodução Assexuada
3.
Plants (Basel) ; 12(2)2023 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-36678955

RESUMO

Although zygotic embryogenesis is usually studied in the field of seed biology, great attention has been paid to the methods used to generate haploid embryos due to their applications in crop breeding. These mainly include two methods for haploid embryogenesis: in vitro microspore embryogenesis and in vivo haploid embryogenesis. Although microspore culture systems and maize haploid induction systems were discovered in the 1960s, little is known about the molecular mechanisms underlying haploid formation. In recent years, major breakthroughs have been made in in vivo haploid induction systems, and several key factors, such as the matrilineal (MTL), baby boom (BBM), domain of unknown function 679 membrane protein (DMP), and egg cell-specific (ECS) that trigger in vivo haploid embryo production in both the crops and Arabidopsis models have been identified. The discovery of these haploid inducers indicates that haploid embryogenesis is highly related to gamete development, fertilization, and genome stability in ealry embryos. Here, based on recent efforts to identify key players in haploid embryogenesis and to understand its molecular mechanisms, we summarize the different paths to haploid embryogenesis, and we discuss the mechanisms of haploid generation and its potential applications in crop breeding. Although these haploid-inducing factors could assist egg cells in bypassing fertilization to initiate embryogenesis or trigger genome elimination in zygotes after fertilization to form haploid embryos, the fertilization of central cells to form endosperms is a prerequisite step for haploid formation. Deciphering the molecular and cellular mechanisms for haploid embryogenesis, increasing the haploid induction efficiency, and establishing haploid induction systems in other crops are critical for promoting the application of haploid technology in crop breeding, and these should be addressed in further studies.

4.
Plants (Basel) ; 12(2)2023 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-36679086

RESUMO

The remarkable species diversity of the genus Sorbus is a result of polyploidization and frequent hybridization between interacting species of different cytotypes. Moreover, hybridization is possible between several parental taxa. Gametophytic apomixis, which is common among polyploid Sorbus taxa, indicates the role of clonal reproduction in the evolutionary stabilization of hybridogeneous genotypes. The precise determination of the origin of seeds and their quantitative evaluation may elucidate inter-cytotype interactions, the potential role of mixed-cytotype populations in evolutionary success, and the long-term survival of some hybrid species. We investigated the reproduction modes of selected species of Sorbus in mixed-cytotype populations in eastern Slovakia, Central Europe. We determined the pollen quality, seed production rate, and the ploidy level of mature trees, as well as the origin of the embryo and endosperm in seeds of the stenoendemics S. amici-petri, S. dolomiticola, and S. hornadensis. The tetraploids S. amici-petri and S. hornadensis are characterized by regular and highly stainable pollen grains and reproduce predominantly via pseudogamous apomixis. In contrast, triploid S. dolomiticola usually has oval, heterogenous, and weakly stainable pollen grains, suggesting male meiotic irregularities. Although seeds originate via pseudogamous apomixis in S. dolomiticola as well, the ploidy level of sperm cells participating in the fertilization of central cells is usually determined by co-occurring species of different cytotypes. This suggests that maintaining mating partners is necessary for the long-term survival of a triploid species. We documented rare BIII hybrids and the residual sexuality in tetraploids. The distribution of seeds of meiotic and apomeiotic origins in S. amici-petri shows bimodal characteristics; however, genotypes with predominantly sexual seed types are rare. Reproduction modes documented in polyploid stenoendemics of Sorbus and inferred microevolutionary intercytotype relationships highlight the mixed-cytotype populations as the source of biodiversity in apomictic plant complexes. We suggest that conservation efforts should focus on maintaining the species and cytotypic diversity of Sorbus populations, especially when it comes to the conservation of triploid species.

5.
J Phycol ; 2023 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-36680561

RESUMO

Scytosiphon is a common intertidal genus widely distributed in temperate coasts worldwide. Recently, eight species have been delimited with molecular tools. Although S. lomentaria is the only species that predominates in the macroalgal literature of the Southwestern Atlantic Ocean (SwAO), unpublished molecular data obtained for a population study of S. lomentaria revealed hidden species diversity of Scytosiphon among the individuals collected from four localities at the SwAO. The aim of this study was to revise the identity and phylogenetic relationships of Scytosiphon from temperate coasts of the SwAO using DNA data. Thalli were collected from the Argentinean coast between 39° S and 43° S, from which cox1 and rbcL sequences were obtained. Phylogenies and haplotype networks were inferred and morphology of gametophytes was studied. Four species were recognized, S. lomentaria, S. promiscuus, S. shibazakiorum and one species that belongs to a complex of species known as "Scytosiphon Atlantic complex". This complex was known to occur only in the North Atlantic, however the results found in this study revealed that it has an extended distribution range that includes the southern hemisphere, where its populations have high genetic diversity and unique haplotypes. The morphological differences among the four species were subtle; denoting that previous Scytosiphon records from the SwAO attributed to the renowned S. lomentaria could represent different species. In addition, sex ratio and genome-wide single nucleotide polymorphisms (SNPs) analyses were done for populations of S. promiscuus presumably introduced to the SwAO, and the results indicated that they included female dominant parthenogenetic populations, which were probably introduced from Japan.

6.
Chromosome Res ; 2022 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-36459298

RESUMO

Unisexual reproduction, which generates clonal offspring, is an alternative strategy to sexual breeding and occurs even in vertebrates. A wide range of non-sexual reproductive modes have been described, and one of the least understood questions is how such pathways emerged and how they mechanistically proceed. The Amazon molly, Poecilia formosa, needs sperm from males of related species to trigger the parthenogenetic development of diploid eggs. However, the mechanism, of how the unreduced female gametes are produced, remains unclear. Cytological analyses revealed that the chromosomes of primary oocytes initiate pachytene but do not proceed to bivalent formation and meiotic crossovers. Comparing ovary transcriptomes of P. formosa and its sexual parental species revealed expression levels of meiosis-specific genes deviating from P. mexicana but not from P. latipinna. Furthermore, several meiosis genes show biased expression towards one of the two alleles from the parental genomes. We infer from our data that in the Amazon molly diploid oocytes are generated by apomixis due to a failure in the synapsis of homologous chromosomes. The fact that this failure is not reflected in the differential expression of known meiosis genes suggests the underlying molecular mechanism may be dysregulation on the protein level or misexpression of a so far unknown meiosis gene, and/or hybrid dysgenesis because of compromised interaction of proteins from diverged genomes.

7.
Mol Ecol ; 2022 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-36527320

RESUMO

Clonal reproduction can provide an advantage for invasive species to establish as it can circumvent inbreeding depression which often plagues introduced populations. The world's most widespread invasive ant, Paratrechina longicornis, was previously found to display a double-clonal reproduction system, whereby both males and queens are produced clonally, resulting in separate male and queen lineages, while workers are produced sexually. Under this unusual reproduction mode, inbreeding is avoided in workers as they carry hybrid interlineage genomes. Despite the ubiquitous distribution of P. longicornis, the significance of this reproductive system for the ant's remarkable success remains unclear, as its prevalence is still unknown. Further investigation into the controversial native origin of P. longicornis is also required to reconstruct the evolutionary histories of double-clonal lineages. Here, we examine genetic variation and characterize the reproduction mode of P. longicornis populations sampled worldwide using microsatellites and mitochondrial DNA sequences to infer the ant's putative native range and the distribution of the double-clonal reproductive system. Analyses of global genetic variations indicate that the Indian subcontinent is a genetic diversity hotspot of this species, suggesting that P. longicornis probably originates from this geographical area. Our analyses revealed that both the inferred native and introduced populations exhibit double-clonal reproduction, with queens and males around the globe belonging to two separate, nonrecombining clonal lineages. By contrast, workers are highly heterozygous because they are first-generation interlineage hybrids. Overall, these data indicate a worldwide prevalence of double clonality in P. longicornis and support the prediction that the unusual genetic system may have pre-adapted this ant for global colonization by maintaining heterozygosity in the worker force and alleviating genetic bottlenecks.

8.
Plants (Basel) ; 11(24)2022 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-36559608

RESUMO

The role of apomeiosis, parthenogenesis, and pseudogamy in the asexual reproduction of some plant groups has not been fully elucidated in relation to species diversification. Quantitative analyses of seed origin may help in gaining better understanding of intercytotypic interactions. Asexual reproduction associated with polyploidy and frequent hybridization plays a crucial role in the evolutionary history of the genus Crataegus in North America. In Europe, the genus represents a taxonomically complex and very difficult species group not often studied using a modern biosystematic approach. We investigated the reproduction pathways in mixed-cytotype populations of selected taxa of Crataegus in eastern Slovakia, Central Europe. The investigated accessions were characterized by seed production data and the ploidy level of mature plants as well as the embryo and endosperm tissues of their seeds determined via flow cytometry. Diploid and polyploid hawthorns reproduce successfully; they also produce high numbers of seeds. An exception is represented by an almost sterile triploid. Diploids reproduce sexually. Polyploids shift to asexual reproduction, but pseudogamy seems to be essential for regular seed development. In rare cases, fertilization of unreduced gametes occurs, which offers opportunity for the establishment of new polyploid cytotypes between diploid sexuals and polyploid asexuals. Opposite to sexual diploids, triploids are obligate, and tetraploids almost obligate apomicts. Apomixis is considered to help stabilize individual weakly differentiated polyploid microspecies. Pseudogamy is a common feature and usually leads to unbalanced maternal to paternal contribution in the endosperm of triploid accessions. Parental contribution to endosperm gene dosage is somehow relaxed in triploids. Our Crataegus plant system resembles reproduction in the diploids and polyploids of North American hawthorns. Our data provide support for the hypothesis that polyploidization, shifts in reproduction modes, and hybridization shape the genus diversity also in Central Europe.

9.
Insects ; 13(12)2022 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-36555050

RESUMO

A widely accepted hypothesis is that parthenogenesis is an evolutionary dead end since it is selectively advantageous in the short term only but results in lowered diversification rates. Triploid apomictic parthenogenesis might represent an exception, as in favorable environments, triploid females are able to produce rare males and diploid females. The aim of the present study was to analyze the modes of reproduction and their evolutionary implications in the parthenogenetic psyllid Cacopsylla ledi (Flor, 1861) from Fennoscandia. The cytogenetic assessment of ploidy levels and the analysis of the COI haplotype revealed two geographically separated bisexual lineages implying genuine bisexual populations. The southern lineage occurring south of latitude 65° N in Finland showed a COI haplotype different from that of parthenogenetic triploids in the same population but identical to the haplotype of specimens in a genuine bisexual population in the Czech Republic. This allows us to suggest that bisexuals in southern Fennoscandia represent the original bisexual C. ledi. By contrast, in the northern bisexual lineage north of latitude 65° N, rare males and diploid females carried the same haplotype as triploids in the same population, having been produced by the triploids. In the Kola Peninsula, a genuine bisexual population of presumably rare male/diploid female origin was discovered. As this population is geographically isolated from populations of the ancestral bisexual C. ledi, it can develop into a new bisexual species through peripatric speciation during evolution. Our findings demonstrate that apomictic triploid parthenogenesis is not necessarily an evolutionary dead end but is able to lead to the emergence of a new bisexual species of parthenogenetic origin.

10.
Insect Biochem Mol Biol ; 153: 103897, 2022 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-36584929

RESUMO

A biocontrol system in New Zealand using the endoparasitoid Microctonus hyperodae is failing, despite once being one of the most successful examples of classical biocontrol worldwide. Though it is of significant economic importance as a control agent, little is known about the genetics of M. hyperodae. In this study, RNA-seq was used to characterise two key traits of M. hyperodae in this system, the venom, critical for the initial success of biocontrol, and the asexual reproduction mode, which influenced biocontrol decline. Expanded characterisation of M. hyperodae venom revealed candidates involved in manipulating the host environment to source nutrition for the parasitoid egg, preventing a host immune response against the egg, as well as two components that may stimulate the host's innate immune system. Notably lacking from the venom-specific expression list was calreticulin, as it also had high expression in the ovaries. In-situ hybridisation revealed this ovarian expression was localised to the follicle cells, which may result in the deposition of calreticulin into the egg exochorion. Investigating the asexual reproduction of M. hyperodae revealed core meiosis-specific genes had conserved expression patterns with the highest expression in the ovaries, suggesting M. hyperodae parthenogenesis involves meiosis and that the potential for sexual reproduction may have been retained. Upregulation of genes involved in endoreduplication provides a potential mechanism for the restoration of diploidy in eggs after meiosis.

11.
J Fish Biol ; 2022 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-36369968

RESUMO

Parthenogenesis has been observed in several elasmobranch species, primarily in public aquaria. The majority of cases of parthenogenesis have occurred either when females were held without males or once a male was removed from a female's habitat. Here we report a second instance of parthenogenesis in a zebra shark female that was housed with conspecific mature males. This study calls into question the conditions under which elasmobranch females undergo parthenogenesis.

12.
BMC Res Notes ; 15(1): 345, 2022 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-36348468

RESUMO

OBJECTIVES: This study is performed in the frame of a bigger study dedicated to genomics and transcriptomics of parthenogenesis in vertebrates. Among vertebrates, obligate parthenogenesis was first described in the lizards of the genus Darevskia. In this genus, all found parthenogenetic species originated via interspecific hybridization. It remains unknown which genetic or genomic factors play a key role in the generation of parthenogenetic organisms. Comparative genomic and transcriptomic analysis of parthenogens and their parental species may elucidate this problem. Darevskia valentini is a paternal species for four (of seven) parthenogens of this genus, which we promote as a particularly important species for the generation of parthenogenetic forms. DATA DESCRIPTION: Total cellular RNA was isolated from kidney and liver tissues using the standard Trizol Tissue RNA Extraction protocol. Sequencing of transcriptome libraries prepared by random fragmentation of cDNA samples was performed on an Illumina HiSeq2500. Obtained raw sequences contained 117,6 million reads with the GC content of 47%. After preprocessing, raw data was assembled by Trinity and produced 491,482 contigs.


Assuntos
Lagartos , Animais , Lagartos/genética , Transcriptoma , Partenogênese/genética , Rim , Fígado , RNA
13.
PeerJ ; 10: e14470, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36447513

RESUMO

Once-useful traits that no longer contribute to fitness tend to decay over time. Here, we address whether the expression of mating-related traits that increase the fitness of sexually reproducing individuals but are likely less useful or even costly to asexual counterparts seems to exhibit decay in the latter. Potamopyrgus antipodarum is a New Zealand freshwater snail characterized by repeated transitions from sexual to asexual reproduction. The frequent coexistence of sexual and asexual lineages makes P. antipodarum an excellent model for the study of mating-related trait loss. Under the presumption (inherent in the Biological Species Concept) that failure to discriminate between conspecific and heterospecific mating partners represents a poor mate choice, we used a mating choice assay including sexual and asexual P. antipodarum females and conspecific (presumed better choice) vs. heterospecific (presumed worse choice) males to evaluate the loss of behavioral traits related to sexual reproduction. We found that sexual females engaged in mating behaviors with conspecific mating partners more frequently and for a greater duration than with heterospecific mating partners. By contrast, asexual females mated at similar frequency and duration as sexual females, but did not mate more often or for longer duration with conspecific vs. heterospecific males. While further confirmation will require inclusion of a more diverse array of sexual and asexual lineages, these results are consistent with a scenario where selection acting to maintain effective mate discrimination in asexual P. antipodarum is weak or ineffective relative to sexual females and, thus, where asexual reproduction is associated with the evolutionary decay of mating-related traits in this system.

14.
Zoological Lett ; 8(1): 14, 2022 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-36435814

RESUMO

The evolution of automixis - i.e., meiotic parthenogenesis - requires several features, including ploidy restoration after meiosis and maintenance of fertility. Characterizing the relative contribution of novel versus pre-existing genes and the similarities in their expression and sequence evolution is fundamental to understand the evolution of reproductive novelties. Here we identify gonads-biased genes in two Bacillus automictic stick-insects and compare their expression profile and sequence evolution with a bisexual congeneric species. The two parthenogens restore ploidy through different cytological mechanisms: in Bacillus atticus, nuclei derived from the first meiotic division fuse to restore a diploid egg nucleus, while in Bacillus rossius, diploidization occurs in some cells of the haploid blastula through anaphase restitution. Parthenogens' gonads transcriptional program is found to be largely assembled from genes that were already present before the establishment of automixis. The three species transcriptional profiles largely reflect their phyletic relationships, yet we identify a shared core of genes with gonad-biased patterns of expression in parthenogens which are either male gonads-biased in the sexual species or are not differentially expressed there. At the sequence level, just a handful of gonads-biased genes were inferred to have undergone instances of positive selection exclusively in the parthenogen species. This work is the first to explore the molecular underpinnings of automixis in a comparative framework: it delineates how reproductive novelties can be sustained by genes whose origin precedes the establishment of the novelty itself and shows that different meiotic mechanisms of reproduction can be associated with a shared molecular ground plan.

15.
Zoolog Sci ; 39(5): 407-412, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36205361

RESUMO

Under favorable conditions, daphnids produce only female neonates by parthenogenesis, while they produce male neonates and start sexual reproduction when they detect cues signaling a deteriorating environment. Identifying the regulatory mechanisms of such cyclical parthenogenesis is important for understanding how organisms adapt to environments and expand their habitats. However, most previous studies using the model species Daphnia magna and Daphnia pulex have focused on production of male offspring (sex determination), whereas the process of meiosis induction in females has not been investigated. Here, we report a simple experimental method to induce meiosis effectively in D. pulex females. Through observations using the new method, we describe the process of sexual reproduction along an individual developmental time course. Meiotic oocytes are oviposited only when females mate within a certain time window, and failure to mate within that window results in subsequent resorption of oocytes, a measure that may increase resistance to starvation. These results further our understanding of regulatory mechanisms and evolutionary processes in the complicated life-history of Daphnia.


Assuntos
Daphnia , Partenogênese , Animais , Daphnia/genética , Feminino , Masculino , Meiose , Oócitos , Reprodução
16.
J Evol Biol ; 35(10): 1387-1395, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36117406

RESUMO

Major hypotheses on sex evolution predict that resource abundance and heterogeneity should either select for or against sexual reproduction. However, seldom have these predictions been explicitly tested in the field. Here, we investigated this question using soil oribatid mites, a diverse and abundant group of soil arthropods whose local communities can be dominated by either sexual or asexual species. First, we refined theoretical predictions by addressing how the effects of resource abundance, heterogeneity and abiotic conditions could modify each other. Then, we estimated the strength of selection for sexual species in local communities while controlling for phylogeny and neutral processes (ecological drift and dispersal), and tested its relation to resource and abiotic gradients. We show that sexual species tended to be favoured with increasing litter amount, a measure of basal resource abundance. Further, there was some evidence that this response occurred mainly under higher tree species richness, a measure of basal resource heterogeneity. This response to resources is unlikely to reflect niche partitioning between reproductive modes, as sexual and asexual species overlapped in trophic niche according to a comparative analysis using literature data on stable isotope ratios. Rather, these findings are consistent with the hypothesis that sex facilitates adaptation by breaking unfavourable genetic associations, an advantage that should increase with effective population size when many loci are under selection and, thus, with resource abundance.


Assuntos
Fome , Ácaros , Animais , Ácaros/genética , Filogenia , Reprodução , Reprodução Assexuada , Solo
17.
Front Cell Dev Biol ; 10: 948778, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36158223

RESUMO

Aggregation of blastomeres is a promising method to improve the developmental competence of blastocysts and may be useful for the production of chimeric animals and the establishment of embryonic stem cell lines by increasing inner cell masses. Here, we determined the optimal conditions for blastomere aggregation using phytohemagglutinin-L (PHA-L) and examined PHA-L efficiency by comparing it with Well of the Well (WOW), a general blastomere aggregation method. As a result, we confirmed that treatment with 15 µg/ml PHA-L for 144 h was effective for blastomere aggregation and embryonic development of three zona-free 2-cell stage embryos (TZ2Es) after parthenogenetic activation (PA). The TZ2Es cultured with PHA-L showed a significantly (p < 0.05) higher blastomere aggregation rate than the WOW method (93.5 ± 1.9% vs. 78.0 ± 8.5%). In addition, our results demonstrated that TZ2Es aggregation through PHA-L improved the quality of PA-derived blastocysts and improved porcine embryonic stem-like cell (pESLCs) seeding efficiency and quality of colonies. It was also observed that PHA-L-derived pESLC could remain undifferentiated and exhibit typical embryonic stem cell pluripotency markers, embryoid body (EB)-forming ability, and differentiation into cell lineages of three germ layers. Pig blastomere aggregation technology is expected to improve embryo quality and the efficiency of embryonic stem cell establishment and embryoid-body formation. It can also be used in blastocyst complementation systems and in the production of chimeric animals.

18.
Genes (Basel) ; 13(9)2022 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-36140737

RESUMO

The extant reptiles are one of the most diverse clades among terrestrial vertebrates and one of a few groups with instances of parthenogenesis. Due to the hybrid origin of parthenogenetic species, reference genomes of the parental species as well as of the parthenogenetic progeny are indispensable to explore the genetic foundations of parthenogenetic reproduction. Here, we report on the first genome assembly of rock lizard Darevskia valentini, a paternal species for several parthenogenetic lineages. The novel genome was used in the reconstruction of the comprehensive phylogeny of Squamata inferred independently from 7369 trees of single-copy orthologs and a supermatrix of 378 conserved proteins. We also investigated Hox clusters, the loci that are often regarded as playing an important role in the speciation of animal groups with drastically diverse morphology. We demonstrated that Hox clusters of D. valentini are invaded with transposons and contain the HoxC1 gene that has been considered to be lost in the amniote ancestor. This study provides confirmation for previous works and releases new genomic data that will contribute to future discoveries on the mechanisms of parthenogenesis as well as support comparative studies among reptiles.


Assuntos
Lagartos , Animais , Genoma/genética , Lagartos/genética , Repetições de Microssatélites , Partenogênese/genética , Filogenia
19.
Ann Bot ; 130(5): 657-669, 2022 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-36112370

RESUMO

BACKGROUND: Urochloa (syn. Brachiaria) is a genus of tropical grasses sown as forage feedstock, particularly in marginal soils. Here we aimed to clarify the genetic diversity and population structure in Urochloa species to understand better how population evolution relates to ploidy level and occurrence of apomictic reproduction. METHODS: We explored the genetic diversity of 111 accessions from the five Urochloa species used to develop commercial cultivars. These accessions were conserved from wild materials collected at their centre of origin in Africa, and they tentatively represent the complete Urochloa gene pool used in breeding programmes. We used RNA-sequencing to generate 1.1 million single nucleotide polymorphism loci. We employed genetic admixture, principal component and phylogenetic analyses to define subpopulations. RESULTS: We observed three highly differentiated subpopulations in U. brizantha, which were unrelated to ploidy: one intermixed with U. decumbens, and two diverged from the former and the other species in the complex. We also observed two subpopulations in U. humidicola, unrelated to ploidy; one subpopulation had fewer accessions but included the only characterized sexual accession in the species. Our results also supported a division of U. decumbens between diploids and polyploids, and no subpopulations within U. ruziziensis and U. maxima. CONCLUSIONS: Polyploid U. decumbens are more closely related to polyploid U. brizantha than to diploid U. decumbens, which supports the divergence of both polyploid groups from a common tetraploid ancestor and provides evidence for the hybridization barrier of ploidy. The three differentiated subpopulations of apomictic polyploid U. brizantha accessions constitute diverged ecotypes, which can probably be utilized in hybrid breeding. Subpopulations were not observed in non-apomictic U. ruziziensis. Sexual Urochloa polyploids were not found (U. brizantha, U. decumbens) or were limited to small subpopulations (U. humidicola). The subpopulation structure observed in the Urochloa sexual-apomictic multiploidy complexes supports geographical parthenogenesis, where the polyploid genotypes exploit the evolutionary advantage of apomixis, i.e. uniparental reproduction and clonality, to occupy extensive geographical areas.


Assuntos
Apomixia , Brachiaria , Brachiaria/genética , Apomixia/genética , Filogenia , Poaceae/genética , Poliploidia
20.
Am J Bot ; 109(10): 1641-1651, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36112611

RESUMO

PREMISE: Parthenogenesis is the capacity of organisms to develop embryos from unfertilized eggs. When parthenogenesis is coupled with unreduced gamete formation (apomeiosis), genetically maternal progeny result. Genetic elucidation of this form of reproduction in plants, apomixis, has important agronomic implications. However, genetic characterization of apomeiosis and parthenogenesis has been problematic in part because the traits usually co-occur and are restricted to polyploids. In this work, the inheritance of parthenogenetic embryo development, by itself, was studied at the diploid level. METHODS: Progeny resulting from a cross between a diploid (2n = 18), heterozygous, parthenogenetic pollen donor, and a diploid, wildtype, sexual seed parent were evaluated. Paternity was tested with conserved orthologous sequence (COS) markers, reproductive development of F1s was evaluated with microscopy of cleared ovules, and an amplified fragment length polymorphism (AFLP) marker (Eagc × Macg.615) co-segregating with parthenogenesis was characterized at the sequence level. RESULTS: Of 102 diploid biparental progeny, 47 exhibited parthenogenetic embryo and endosperm development, and 55 lacked development of the egg and central cell. This result is consistent with Mendelian inheritance for a single locus (P = 0.43). Isolation and sequencing of the AFLP marker indicates that it is likely a portion of a Ty-Gypsy retrotransposon. Attempts to develop a sequence-characterized amplified region marker from the AFLP were unsuccessful. CONCLUSIONS: This work shows that parthenogenesis can be transmitted simply at the diploid level. This advance is key in the development of a tractable system in Erigeron aimed at the identification of the parthenogenesis locus using genetic mapping strategies.


Assuntos
Erigeron , Magnoliopsida , Diploide , Erigeron/genética , Análise do Polimorfismo de Comprimento de Fragmentos Amplificados , Magnoliopsida/genética , Partenogênese/genética , Desenvolvimento Embrionário
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