Obligatory parthenogenesis in vertebrates is restricted to squamate reptiles and evolved through hybridisation. Parthenogens can hybridise with sexual species, resulting in individuals with increased ploidy levels. We describe two successive hybridisations of the parthenogenetic butterfly lizards (genus Leiolepis) in Vietnam with a parental sexual species. Contrary to previous proposals, we document that parthenogenetic L. guentherpetersi has mitochondrial DNA and two haploid sets from L. guttata and one from L. reevesii, suggesting that it is the result of a backcross of a parthenogenetic L. guttata × L. reevesii hybrid with a L. guttata male increasing ploidy from 2n to 3n. Within the range of L. guentherpetersi, we found an adult tetraploid male with three L. guttata and one L. reevesii haploid genomes. It probably originated from fertilisation of an unreduced triploid L. guentherpetersi egg by a L. guttata sperm. Although its external morphology resembles that of the maternal species, it possessed exceptionally large erythrocytes and was likely sterile. As increased ploidy level above triploidy or tetraploidy appears to be harmful for amniotes, all-female asexual lineages should evolve a strategy to prevent incorporation of other haploid genomes from a sexual species by avoiding fertilisation by sexual males.
- Klíčová slova
- Leiolepis, Hybridisation, Meiosis, Parthenogenesis, Tetraploidy, Vietnam,
- MeSH
- hybridizace genetická MeSH
- ještěři * genetika MeSH
- mitochondriální DNA genetika MeSH
- partenogeneze * genetika MeSH
- tetraploidie * MeSH
- triploidie * MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- mitochondriální DNA MeSH
Among vertebrates, obligate parthenogenesis occurs exclusively in squamate reptiles. Premeiotic endoreplication in a small subset of developing oocytes has been documented as the mechanism of production of unreduced eggs in minutely explored obligate parthenogenetic lineages, namely in teiids and geckos. The situation in the lacertid genus Darevskia has been discussed for decades. Certain observations suggested that the ploidy level is restored during egg formation through a fusion of egg and polar body nuclei in Darevskia unisexualis and D. armeniaca. In this study, we re-evaluated the fusion hypothesis by studying diplotene chromosomes in adult females of sexual species D. raddei nairensis and obligate parthenogens D. armeniaca, D. dahli and D. unisexualis. We revealed 19 bivalents in the sexual species and 38 bivalents in the diploid obligate parthenogens, which uncovers premeiotic endoreplication as the mechanism of the production of non-reduced eggs in parthenogenetic females. The earlier contradicting reports can likely be attributed to the difficulty in identifying mispairing of chromosomes in pachytene, and the fact that in parthenogenetic reptiles relying on premeiotic endoreplication only a small subset of developing oocytes undergo genome doubling and overcome the pachytene checkpoint. This study highlights co-option of premeiotic endoreplication for escape from sexual reproduction in all independent hybrid origins of obligate parthenogenesis in vertebrates studied to date.
- Klíčová slova
- Lacertidae, asexuality, meiosis, obligatory parthenogenesis, reptiles, vertebrates,
- MeSH
- ještěři * fyziologie genetika MeSH
- meióza MeSH
- partenogeneze * MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Social insects have developed a broad diversity of nesting and foraging strategies. One of these, inquilinism, occurs when one species (the inquiline) inhabits the nest built and occupied by another species (the host). Obligatory inquilines must overcome strong constraints upon colony foundation and development, due to limited availability of host colonies. To reveal how inquilinism shapes reproductive strategies in a termite host-inquiline dyad, we carried out a microsatellite marker study on Inquilinitermes inquilinus and its host Constrictotermes cavifrons. The proportion of simple, extended and mixed families was recorded in both species, as well as the presence of neotenics, parthenogenesis and multiple foundations. Most host colonies (95%) were simple families and all were monodomous. By contrast, the inquiline showed a higher proportion of extended (30%) and mixed (5%) families, and frequent neotenics (in 25% of the nests). This results from the simultaneous foundation in host nests of numerous incipient colonies, which, as they grow, may compete, fight, or merge. We also documented the use of parthenogenesis by female-female pairs. In conclusion, the classical monogamous colony pattern of the host species suggests uneventful development of simple foundations dispersed in the environment, in accordance with the wide distribution of their resources. By contrast, the multiple reproductive patterns displayed by the inquiline species reveal strong constraints on foundation sites: founders first concentrate into host nests, then must attempt to outcompete or absorb the neighbouring foundations to gain full control of the resources provided by the host nest.
- Klíčová slova
- Isoptera, Termitidae, breeding systems, inquilinism, microsatellite, reproductive strategies,
- MeSH
- hnízdění MeSH
- Isoptera * genetika MeSH
- mikrosatelitní repetice * genetika MeSH
- partenogeneze * genetika MeSH
- rozmnožování genetika MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The combination of a flow cytometric seed screen and genotyping of each single seed offers a cost-effective approach to detecting complex reproductive pathways in flowering plants. Reproduction may be seen as one of the driving forces of evolution. Flow cytometric seed screen and genotyping of parents and progeny are commonly employed techniques to discern various modes of reproduction in flowering plants. Nevertheless, both methods possess limitations constraining their individual capacity to investigate reproductive modes thoroughly. We implemented both methods in a novel manner to analyse reproduction pathways using a carefully selected material of parental individuals and their seed progeny. The significant advantage of this approach lies in its ability to apply both methods to a single seed. The introduced methodology provides valuable insights into discerning the levels of apomixis, sexuality, and selfing in complex Rubus taxa. The results may be explained by the occurrence of automixis in Rubus, which warrants further investigation. The approach showcased its effectiveness in a different apomictic system, specifically in Taraxacum. Our study presents a comprehensive methodological approach for determining the mode of reproduction where flow cytometry loses its potential. It provides a reliable and cost-effective method with significant potential in biosystematics, population genetics, and crop breeding.
- Klíčová slova
- Rubus, Taraxacum, Apomixis, Automixis, FCSS, SSR-seq,
- MeSH
- apomixie * genetika fyziologie MeSH
- genotyp MeSH
- průtoková cytometrie * MeSH
- rozmnožování MeSH
- semena rostlinná * genetika fyziologie MeSH
- Taraxacum fyziologie genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The concept of a standardized reference diet (SRD) is used in laboratory model organisms to ensure nutritional control between studies and laboratories. Although models using the genetically identical, all female parthenogenetic marbled crayfish (Procambarus virginalis) are growing in popularity, research into nutrition in this species still has many knowledge gaps. To fast track the development of a SRD in terms of protein and amino acids (SRDprotein) for this species, we first analyzed the composition of its body amino acids to determine the ideal protein concept (IPC) of indispensable amino acids in wild-caught P. virginalis (which had an unusually high preponderance of leucine and arginine). Then, we strategically evaluated three common clusters of types of fish feed: (1) ornamental fish feed (SER) fortified with a naturally occurring alga (Spirulina). This type of feed was protein-high in arginine and leucine (SER + SPI) that fulfils the species' IPC for iso-protein (~ 40%), iso-phosphorus (~ 0.8%) and near iso-energetic (~ 475 kcal 100 g-1); (2) freeze-dried live feed consisting of chironomid larvae (CHI) fortified with Spirulina (CHI + SPI) that fulfils the IPC for iso-protein (~ 46%), iso-phosphorus (~ 0.7%) and near iso-energetic (~ 405 kcal 100 g-1); and (3) a commercially standardized 'starter diet' for carnivorous fish larvae (FISH) and post-larval shrimps (SHRIMP) with iso-protein (~ 56%) and iso-phosphorus (~ 1.6%). A total of six diets, embracing a diverse range of proteinaceous feeds, were used in a 100-day ad libitum feeding and growth trial. The FISH group outperformed all the other groups (p < 0.05) and our exploratory multivariate analysis revealed an ideal demand of > 44% protein (tailored to deliver high arginine 3% and leucine 4%, followed by the usual lysine > 3.5% and methionine 1.2%) but also the lowest carbohydrate level (21%). For SRDprotein, our findings show that the FISH diet is ideal and suggest the possibilities of using a CHI + SPI diet for further optimization (more economic use of protein and phosphorus).
- Klíčová slova
- Amino acids, Ideal protein, Laboratory diet, Laboratory model, Nutritional control,
- MeSH
- aminokyseliny * metabolismus MeSH
- dieta veterinární MeSH
- dietní proteiny metabolismus MeSH
- fyziologie výživy zvířat MeSH
- krmivo pro zvířata * analýza MeSH
- partenogeneze MeSH
- severní raci * fyziologie MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- aminokyseliny * MeSH
- dietní proteiny MeSH
Fatty acid accumulation was studied in the parthenogenetic all-female marbled crayfish Procambarus virginalis using six arbitrarily designed experimental feeds and related to individuals with glair glands (sexual maturity) after 100 days of ad libitum feeding at 21 °C, including gravid females from the wild as a reference. Fatty acids 16:0 and 18:1n-9 comprised 40% of the total amount of fatty acids and tended to up-concentrate in bodies. Shorter chain 14:0 depleted from feed to body. Across diets, there was a concomitant decrease in precursor fatty acid and increase in product fatty acid, such as reinforcements in monounsaturated fatty acid (18:1n-9), eicosanoid precursors 20:4n-6 (arachidonic acid, ARA) and 20:5n-3 (eicosapentaenoic acid, EPA) in-vivo, but not 22:6n-3 (docosahexaenoic acid, DHA) except when deficient in CHI or CHI + SPI diets. Saturation kinetics modeling (R2 0.7-0.9, p < 0.05) showed that when the ARA share is ~ 1%, the EPA share is ~ 8%, and the DHA share is ~ 2% in the food lipids, the accumulation of fatty acids in body lipids levels off. The lowest DHA in the CHI (0% glair glands) or CHI + SPI (0-3.9% glair glands) diets, and the lowest ARA in SER (0% glair glands) or SER + SPI (0-3% glair glands) diets, were synchronous with negligible sexual maturity despite a wide range of observed specific growth rates (2.77-3.60% per day), body size (0.44-0.84 g), ≤ 5% crude lipid and 40-46% crude protein feed. The FISH and SHRIMP diets (56% protein, 11-14% lipid) with the highest ARA, EPA, and DHA together seem to be the most conducive diets for sexual maturity (up to 20% of individuals with glair glands). We propose a fatty acid profile mimicking the FISH or SHRIMP diets as a starting point for designing the lipid content required in the marbled crayfish standardized reference diet.
- MeSH
- dieta * MeSH
- krmivo pro zvířata * analýza MeSH
- mastné kyseliny * metabolismus analýza MeSH
- partenogeneze MeSH
- severní raci * metabolismus růst a vývoj MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- mastné kyseliny * MeSH
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.
- Klíčová slova
- Rubus subgen. Rubus, Apomixis, ddRADseq, geographical parthenogenesis, introgression, private alleles,
- MeSH
- apomixie genetika MeSH
- biologická evoluce MeSH
- fylogeneze MeSH
- fylogeografie * MeSH
- genetická variace MeSH
- partenogeneze genetika MeSH
- Rosaceae * genetika fyziologie MeSH
- tok genů MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Asie MeSH
- Evropa MeSH
PREMISE: Apomixis in ferns is relatively common and obligatory. Sterile hybrids may restore fertility via apomixis at a cost of long-term genetic stagnation. In this study, we outlined apomixis as a possible temporary phase leading to sexuality and analyzed factors relating to transitioning to and away from apomixis, such as unreduced and reduced spore formation in apomict and apo-sex hybrid ferns. METHODS: We analyzed the genome size of 15 fern species or hybrids ("taxa") via flow cytometry. The number of reduced and unreduced gametophytes was established as a proxy for viable spore formation of either type. We also calculated the spore abortion ratio (sign of reduced spores) in several taxa, including the apo-sex hybrid Dryopteris × critica and its 16 apomictically formed offspring. RESULTS: Four of 15 sampled taxa yielded offspring variable in genome size. Specifically, each variable taxon formed one viable reduced plant among 12-451 sampled gametophytes per taxon. Thus, haploid spore formation in the studied apomicts was very rare but possible. Spore abortion analyses indicated gradually decreasing abortion (haploid spore formation) over time. In Dryopteris × critica, abortion decreased from 93.8% to mean 89.5% in one generation. CONCLUSIONS: Our results support apomixis as a transitionary phase toward sexuality. Newly formed apomicts hybridize with sexual relatives and continue to form haploid spores early on. Thus, they may get the genomic content necessary for regular meiosis and restore sexuality. If the missing relative goes extinct, the lineage gets locked into apomixis as may be the case with the Dryopteris affinis complex.
- Klíčová slova
- Dryopteris, apogamy, apomixis, evolutionary biology, fern life cycle, flow cytometry, gametophyte, genome size, pteridophytes, reproduction,
- MeSH
- apomixie * genetika MeSH
- délka genomu * MeSH
- genom rostlinný * MeSH
- hybridizace genetická MeSH
- kapradiny * genetika fyziologie MeSH
- spory * fyziologie genetika MeSH
- Publikační typ
- časopisecké články MeSH
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.
- Klíčová slova
- Rubus ser. Glandulosi, apomixis, clonal turnover, genotypic diversity, geographical parthenogenesis, niche differentiation,
- MeSH
- apomixie * MeSH
- partenogeneze genetika MeSH
- ploidie MeSH
- polyploidie MeSH
- Rubus * MeSH
- Publikační typ
- časopisecké články MeSH
In higher plants, sexual reproduction is characterized by meiosis of the first cells of the germlines, and double fertilization of the egg and central cell after gametogenesis. In contrast, in apomicts of the genus Boechera, meiosis is omitted or altered and only the central cell requires fertilization, while the embryo forms parthenogenetically from the egg cell. To deepen the understanding of the transcriptional basis underlying these differences, we applied RNA-seq to compare expression in reproductive tissues of different Boechera accessions. This confirmed previous evidence of an enrichment of RNA helicases in plant germlines. Furthermore, few RNA helicases were differentially expressed in female reproductive ovule tissues harboring mature gametophytes from apomictic and sexual accessions. For some of these genes, we further found evidence for a complex recent evolutionary history. This included a homolog of Arabidopsis thaliana FASCIATED STEM4 (FAS4). In contrast to AtFAS4, which is a single-copy gene, FAS4 is represented by three homologs in Boechera, suggesting a potential for subfunctionalization to modulate reproductive development. To gain first insights into functional roles of FAS4, we studied Arabidopsis lines carrying mutant alleles. This identified the crucial importance of AtFAS4 for reproduction, as we observed developmental defects and arrest during male and female gametogenesis.
- Klíčová slova
- Boechera, FASCIATED STEM4, Apomixis, RNA helicase, evolution, gametogenesis, reproduction, transcriptome,
- MeSH
- apomixie * genetika MeSH
- Arabidopsis * genetika MeSH
- biologická evoluce MeSH
- Brassicaceae * genetika MeSH
- buněčný cyklus MeSH
- rozmnožování genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
