Offspring stability
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Speciation may occur when the genomes of two populations accumulate genetic incompatibilities and/or chromosomal rearrangements that prevent inter-breeding in nature. Chromosome stability is critical for survival and faithful transmission of the genome, and hybridization can compromise this. However, the role of chromosomal stability on hybrid incompatibilities has rarely been tested in recently diverged populations. Here, we test for chromosomal instability in hybrids between nascent species, the 'dwarf' and 'normal' lake whitefish (Coregonus clupeaformis). We examined chromosomes in pure embryos, and healthy and malformed backcross embryos. While pure individuals displayed chromosome numbers corresponding to the expected diploid number (2n = 80), healthy backcrosses showed evidence of mitotic instability through an increased variance of chromosome numbers within an individual. In malformed backcrosses, extensive aneuploidy corresponding to multiples of the haploid number (1n = 40, 2n = 80, 3n = 120) was found, suggesting meiotic breakdown in their F1 parent. However, no detectable chromosome rearrangements between parental forms were identified. Genomic instability through aneuploidy thus appears to contribute to reproductive isolation between dwarf and normal lake whitefish, despite their very recent divergence (approx. 15-20 000 generations). Our data suggest that genetic incompatibilities may accumulate early during speciation and limit hybridization between nascent species.
- Klíčová slova
- Coregonus, cytogenetics, genome stability, salmonid, speciation,
- MeSH
- aneuploidie * MeSH
- chromozomální nestabilita MeSH
- embryo nesavčí abnormality MeSH
- hybridizace genetická MeSH
- reprodukční izolace MeSH
- rozmnožování genetika MeSH
- Salmonidae abnormality embryologie genetika MeSH
- vznik druhů (genetika) MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
IMPORTANCE: Maternal mental health problems during pregnancy are associated with altered neurodevelopment in offspring, but the long-term relationship between these prenatal risk factors and offspring brain structure in adulthood remains incompletely understood due to a paucity of longitudinal studies. OBJECTIVE: To evaluate the association between exposure to maternal depression in utero and offspring brain age in the third decade of life, and to evaluate recent stressful life events as potential moderators of this association. DESIGN, SETTING, AND PARTICIPANTS: This cohort study examined the 30-year follow-up of a Czech prenatal birth cohort with a within-participant design neuroimaging component in young adulthood conducted from 1991 to 2022. Participants from the European Longitudinal Study of Pregnancy and Childhood prenatal birth cohort were recruited for 2 magnetic resonance imaging (MRI) follow-ups, one between ages 23 and 24 years (early 20s) and another between ages 28 and 30 years (late 20s). EXPOSURES: Maternal depression during pregnancy; stressful life events in the past year experienced by the young adult offspring. MAIN OUTCOMES AND MEASURES: Gap between estimated neuroanatomical vs chronological age at MRI scan (brain age gap estimation [BrainAGE]) calculated once in participants' early 20s and once in their late 20s, and pace of aging calculated as the differences between BrainAGE at the 2 MRI sessions in young adulthood. RESULTS: A total of 260 individuals participated in the second neuroimaging follow-up (mean [SD] age, 29.5 [0.6] years; 135 [52%] male); MRI data for both time points and a history of maternal depression were available for 110 participants (mean [SD] age, 29.3 [0.6] years; 56 [51%] male). BrainAGE in participants' early 20s was correlated with BrainAGE in their late 20s (r = 0.7, P < .001), and a previously observed association between maternal depression during pregnancy and BrainAGE in their early 20s persisted in their late 20s (adjusted R2 = 0.04; P = .04). However, no association emerged between maternal depression during pregnancy and the pace of aging between the 2 MRI sessions. The stability of the associations between maternal depression during pregnancy and BrainAGE was also supported by the lack of interactions with recent stress. In contrast, more recent stress was associated with greater pace of aging between the 2 MRI sessions, independent of maternal depression (adjusted R2 = 0.09; P = .01). CONCLUSIONS AND RELEVANCE: The findings of this cohort study suggest that maternal depression and recent stress may have independent associations with brain age and the pace of aging, respectively, in young adulthood. Prevention and treatment of depression in pregnant mothers may have long-term implications for offspring brain development.
- MeSH
- deprese * MeSH
- dítě MeSH
- dospělé děti MeSH
- dospělí MeSH
- kohortové studie MeSH
- lidé MeSH
- longitudinální studie MeSH
- mladý dospělý MeSH
- mozek diagnostické zobrazování MeSH
- těhotenství MeSH
- zpožděný efekt prenatální expozice * MeSH
- Check Tag
- dítě MeSH
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Polyploidization is a common phenomenon in the evolution of flowering plants. However, only a few genes controlling polyploid genome stability, fitness, and reproductive success are known. Here, we studied the effects of loss-of-function mutations in NSE2 and NSE4A subunits of the Structural Maintenance of Chromosomes 5/6 (SMC5/6) complex in autotetraploid Arabidopsis thaliana plants. The diploid nse2 and nse4a plants show partially reduced fertility and produce about 10% triploid offspring with two paternal and one maternal genome copies. In contrast, the autotetraploid nse2 and nse4a plants were almost sterile and produced hexaploid and aneuploid progeny with the extra genome copies or chromosomes coming from both parents. In addition, tetraploid mutants had more severe meiotic defects, possibly due to the presence of four homologous chromosomes instead of two. Overall, our study suggests that the SMC5/6 complex is an important player in the maintenance of tetraploid genome stability and that autotetraploid Arabidopsis plants have a generally higher frequency of but also higher tolerance for aneuploidy compared to diploids.
- Klíčová slova
- NSE2, SMC5/6 complex, genome stability, meiosis, polyploidy, seed development,
- Publikační typ
- časopisecké články MeSH
The Drosophila genomic fragment Dm111 and the selectable dominant nptII gene were transferred via a Ti-vector into tobacco plants in order to check the structural and functional stability of transgenes in plants and their progeny. Southern blot analyses clearly showed that transgenes were integrated intact and did not suffer from any gross DNA rearrangements. Contrary to this structural stability, not all of the transgenic plants and their offspring displayed the original and stable expression of the nptII gene. The levels of the NPTII enzyme strongly varied in individual plants and did not depend on the copy number of the nptII gene. Both the non-stable nptII expression during the individual plant development in one original transgenic tobacco and some irregularities in segregation ratios after self-pollination indicated that epigenetic effects due to methylation of DNA modulated the expression of foreign genes in transgenic plants. This conclusion was supported by a spontaneous and 5-azacytidine-stimulated demethylation.
- MeSH
- DNA genetika MeSH
- Drosophila genetika MeSH
- Escherichia coli genetika MeSH
- fosfotransferasy genetika metabolismus MeSH
- hybridizace nukleových kyselin MeSH
- jedovaté rostliny MeSH
- kanamycin MeSH
- kanamycinkinasa MeSH
- klonování DNA MeSH
- léková rezistence genetika MeSH
- plazmidy MeSH
- rekombinantní DNA * MeSH
- restrikční enzymy MeSH
- Rhizobium genetika MeSH
- rostliny genetika MeSH
- tabák MeSH
- transfekce * MeSH
- transformace genetická MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- DNA MeSH
- fosfotransferasy MeSH
- kanamycin MeSH
- kanamycinkinasa MeSH
- rekombinantní DNA * MeSH
- restrikční enzymy MeSH
Animal bodies are inhabited by a taxonomically and functionally diverse community of symbiotic and commensal microorganisms. From an ecological and evolutionary perspective, inter-individual variation in host-associated microbiota contributes to physiological and immune system variation. As such, host-associated microbiota may be considered an integral part of the host's phenotype, serving as a substrate for natural selection. This assumes that host-associated microbiota exhibits high temporal stability, however, and that its composition is shaped by trans-generational transfer or heritable host-associated microbiota modulators encoded by the host genome. Although this concept is widely accepted, its crucial assumptions have rarely been tested in wild vertebrate populations. We performed 16S rRNA metabarcoding on an extensive set of fecal microbiota (FM) samples from an insectivorous, long-distance migratory bird, the barn swallow (Hirundo rustica). Our data revealed clear differences in FM among juveniles and adults as regards taxonomic and functional composition, diversity and co-occurrence network complexity. Multiple FM samples from the same juvenile or adult collected within single breeding seasons exhibited higher similarity than expected by chance, as did adult FM samples over two consecutive years. Despite low effect sizes for FM stability over time at the community level, we identified an adult FM subset with relative abundances exhibiting significant temporal consistency, possibly inducing long-term effects on the host phenotype. Our data also indicate a slight maternal (but not paternal) effect on FM composition in social offspring, though this is unlikely to persist into adulthood. We discuss our findings in the context of both evolution and ecology of microbiota vs. host interactions and barn swallow biology.
- Klíčová slova
- barn swallow, fecal microbiota, gastrointestinal tract, metagenome, microbiome, symbiosis,
- Publikační typ
- časopisecké články MeSH
BACKGROUND: Celosia argentea is a widely recognized plant for its ornamental qualities and therapeutic uses in traditional medicine. As demand for such multipurpose plants grows, enhancing its phenotypic and physiological traits could further expand its commercial potential. Polyploidization, particularly through chemical treatments like oryzalin, offers a method to induce genetic variation and potentially improve desirable traits in plants. RESULTS: Tetraploid (2n = 4×= 36) nodal segments of C. argentea were treated with oryzalin under in vitro conditions, resulting in successful induction of octoploidy (2n = 8×= 72). Flow cytometry and chromosome counting confirmed polyploidization, with the highest induction rate achieved using 40 µM oryzalin for 24 h. Comparative analyses between octoploid and tetraploid plants revealed significant differences in morphological traits, including increased stem and leaf thickness, larger leaf area, inflorescence characteristics and more compact growth in the octoploids. Additionally, octoploids exhibited enhanced chlorophyll content and altered photosynthetic characteristics, along with notable changes in stomatal size and density. Ploidy stability was maintained across generations, ensuring the heritability of the induced traits. CONCLUSIONS: In vitro polyploidization in C. argentea led to significant phenotypic and physiological improvements, demonstrating its potential for application in ornamental horticulture and plant breeding. This research contributes to the understanding of the impact of in vitro polyploidization on plant development, offering insights for the commercial cultivation and enhancement of C. argentea. CLINICAL TRIAL NUMBER: Not applicable.
- Klíčová slova
- Chromosome doubling, Cockscomb, Crop improvement, Offspring stability, Oryzalin, Polyploid induction, Polyploidization,
- MeSH
- Celosia * genetika MeSH
- chlorofyl metabolismus MeSH
- dinitrobenzeny farmakologie MeSH
- fenotyp MeSH
- fotosyntéza * MeSH
- listy rostlin genetika růst a vývoj fyziologie MeSH
- polyploidie * MeSH
- sulfanilamidy MeSH
- tetraploidie * MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
- Názvy látek
- chlorofyl MeSH
- dinitrobenzeny MeSH
- oryzalin MeSH Prohlížeč
- sulfanilamidy MeSH
Chromosome organization, dynamics and stability are required for successful passage through cellular generations and transmission of genetic information to offspring. The key components involved are Structural maintenance of chromosomes (SMC) complexes. Cohesin complex ensures proper chromatid alignment, condensin complex chromosome condensation and the SMC5/6 complex is specialized in the maintenance of genome stability. Here we summarize recent knowledge on the composition and molecular functions of SMC5/6 complex. SMC5/6 complex was originally identified based on the sensitivity of its mutants to genotoxic stress but there is increasing number of studies demonstrating its roles in the control of DNA replication, sister chromatid resolution and genomic location-dependent promotion or suppression of homologous recombination. Some of these functions appear to be due to a very dynamic interaction with cohesin or other repair complexes. Studies in Arabidopsis indicate that, besides its canonical function in repair of damaged DNA, the SMC5/6 complex plays important roles in regulating plant development, abiotic stress responses, suppression of autoimmune responses and sexual reproduction.
- Klíčová slova
- DNA damage repair, SMC5/6, Structural maintenance of chromosomes, chromatin, chromosomes, genome stability,
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Chromatin-based processes are essential for cellular functions. Structural maintenance of chromosomes (SMCs) are evolutionarily conserved molecular machines that organize chromosomes throughout the cell cycle, mediate chromosome compaction, promote DNA repair, or control sister chromatid attachment. The SMC5/6 complex is known for its pivotal role during the maintenance of genome stability. However, a dozen recent plant studies expanded the repertoire of SMC5/6 complex functions to the entire plant sexual reproductive phase. The SMC5/6 complex is essential in meiosis, where its activity must be precisely regulated to allow for normal meiocyte development. Initially, it is attenuated by the recombinase RAD51 to allow for efficient strand invasion by the meiosis-specific recombinase DMC1. At later stages, it is essential for the normal ratio of interfering and non-interfering crossovers, detoxifying aberrant joint molecules, preventing chromosome fragmentation, and ensuring normal chromosome/sister chromatid segregation. The latter meiotic defects lead to the production of diploid male gametes in Arabidopsis SMC5/6 complex mutants, increased seed abortion, and production of triploid offspring. The SMC5/6 complex is directly involved in controlling normal embryo and endosperm cell divisions, and pioneer studies show that the SMC5/6 complex is also important for seed development and normal plant growth in cereals.
- Klíčová slova
- SMC5/6 complex, fertility, genome stability, meiosis, polyploidy, reproductive development, seed,
- MeSH
- Arabidopsis * genetika metabolismus MeSH
- chromatidy metabolismus MeSH
- meióza MeSH
- oprava DNA MeSH
- proteiny buněčného cyklu * genetika metabolismus MeSH
- rekombinasy genetika MeSH
- rozmnožování genetika MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- Názvy látek
- proteiny buněčného cyklu * MeSH
- rekombinasy MeSH
The sequencing of human genome was completed in 2001. The position of particular DNA base is established-i.e. we know all "letters" in the "book" but we understand only limited number of "words" i. e. only limited number of genes was identified. And the human genome consists of about 30,000 genes from which through the mechanism of alternative RNA splicing more than 100,000 genes can be derived. All the genes of one individual form the genotype. The expression of genotype in particular environment forms the phenotype. What is not present in genotype can neither be present in phenotype. In the last decade a substantial progress was achieved in understanding of membrane processes mostly due to research of relatively rare inherited monogenous arrhythmic syndromes--first of all the long QT syndrome. It is caused by mutations in ion channel genes and it provides a model of arrhythmogenesis on molecular level. Ventricular arrhythmias are important cause of mortality in patients with cardiovascular diseases. New studies have provided strong evidence for familial sudden cardiac death (SCD) aggregation and therefore also genetic influence. Parental history of SCD increases the relative risk of SCD for offspring to 1.8. In the case of both maternal and paternal SCD events the risk for offspring is a remarkable 9.4. There are 3 pathways by which genetic variation may contribute to risk for SCD: 1. alterations in electrogenesis and conduction, 2. formation and stability of atherosclerotic plaque, thrombogenesis and ischemia within the coronary circulation, 3. control of myocardial excitability and vascular motorics. The main objective of both today and future research is identification of inheritable "molecular" risk factors of arrhythmias. Understanding of this level of pathophysiological processes will subsequently lead to new generation of both diagnostic and therapeutic methods.
- MeSH
- iontové kanály genetika MeSH
- lidé MeSH
- mutace MeSH
- náhlá srdeční smrt etiologie MeSH
- rizikové faktory MeSH
- srdeční arytmie genetika MeSH
- syndrom dlouhého QT genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- anglický abstrakt MeSH
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- iontové kanály MeSH
Structural maintenance of chromosome 5/6 (SMC5/6) complex is a crucial factor for preserving genome stability. Here, we show that mutants for several Arabidopsis (Arabidopsis thaliana) SMC5/6 complex subunits produce triploid offspring. This phenotype is caused by a meiotic defect leading to the production of unreduced male gametes. The SMC5/6 complex mutants show an absence of chromosome segregation during the first and/or the second meiotic division, as well as a partially disorganized microtubule network. Importantly, although the SMC5/6 complex is partly required for the repair of SPO11-induced DNA double-strand breaks, the nonreduction described here is SPO11-independent. The measured high rate of ovule abortion suggests that, if produced, such defects are maternally lethal. Upon fertilization with an unreduced pollen, the unbalanced maternal and paternal genome dosage in the endosperm most likely causes seed abortion observed in several SMC5/6 complex mutants. In conclusion, we describe the function of the SMC5/6 complex in the maintenance of gametophytic ploidy in Arabidopsis.
