In recent years, we have seen an increasing amount of evidence pointing to the existence of a non-genetic heredity of the effects of events such as separation from parents, threat to life, or other traumatising experiences such as famine. This heredity is often mediated by epigenetic regulations of gene expression and may be transferred even across several generations. In this review, we focus on studies which involve transgenerational epigenetic inheritance (TEI), with a short detour to intergenerational studies focused on the inheritance of trauma or stressful experiences. The reviewed studies show a plethora of universal changes which stress exposure initiates on multiple levels of organisation ranging from hormonal production and the hypothalamic-pituitary-adrenal (HPA) axis modulation all the way to cognition, behaviour, or propensity to certain psychiatric or metabolic disorders. This review will also provide an overview of relevant methodology and difficulties linked to implementation of epigenetic studies. A better understanding of these processes may help us elucidate the evolutionary pathways which are at work in the course of emergence of the diseases and disorders associated with exposure to trauma, either direct or in a previous generation.

• Keywords
• DNA methylation, HPA axis, RNA, stress, transgenerational epigenetic inheritance, trauma,
• MeSH
• Databases, Genetic MeSH
• Heredity * MeSH
• Epigenesis, Genetic * genetics   MeSH
• Mammals genetics   MeSH
• Inheritance Patterns MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH

Due to the accelerating climate change, it is crucial to understand how plants adapt to rapid environmental changes. Such adaptation may be mediated by epigenetic mechanisms like DNA methylation, which could heritably alter phenotypes without changing the DNA sequence, especially across clonal generations. However, we are still missing robust evidence of the adaptive potential of DNA methylation in wild clonal populations. Here, we studied genetic, epigenetic and transcriptomic variation of Fragaria vesca, a predominantly clonally reproducing herb. We examined samples from 21 natural populations across three climatically distinct geographic regions, as well as clones of the same individuals grown in a common garden. We found that epigenetic variation was partly associated with climate of origin, particularly in non-CG contexts. Importantly, a large proportion of this variation was heritable across clonal generations. Additionally, a subset of these epigenetic changes affected the expression of genes mainly involved in plant growth and responses to pathogen and abiotic stress. These findings highlight the potential influence of epigenetic changes on phenotypic traits. Our findings indicate that variation in DNA methylation, which can be environmentally inducible and heritable, may enable clonal plant populations to adjust to their environmental conditions even in the absence of genetic adaptation.

• Keywords
• adaptation, climate change, clonal plant, ecological epigenetics, environmentally induced epigenetic variation, inheritance, natural populations, transposons,
• MeSH
• Clone Cells MeSH
• Epigenesis, Genetic MeSH
• Phenotype MeSH
• Fragaria * genetics   MeSH
• Humans MeSH
• DNA Methylation * genetics   MeSH
• Plants genetics   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH

Chromatin is assembled by histone chaperones such as chromatin assembly factor CAF-1. We had noticed that vigor of Arabidopsis thaliana CAF-1 mutants decreased over several generations. Because changes in mutant phenotype severity over generations are unusual, we asked how repeated selfing of Arabidopsis CAF-1 mutants affects phenotype severity. CAF-1 mutant plants of various generations were grown, and developmental phenotypes, transcriptomes and DNA cytosine-methylation profiles were compared quantitatively. Shoot- and root-related growth phenotypes were progressively more affected in successive generations of CAF-1 mutants. Early and late generations of the fasciata (fas)2-4 CAF-1 mutant displayed only limited changes in gene expression, of which increasing upregulation of plant defense-related genes reflects the transgenerational phenotype aggravation. Likewise, global DNA methylation in the sequence context CHG but not CG or CHH (where H = A, T or C) changed over generations in fas2-4. Crossing early and late generation fas2-4 plants established that the maternal contribution to the phenotype severity exceeds the paternal contribution. Together, epigenetic rather than genetic mechanisms underlie the progressive developmental phenotype aggravation in the Arabidopsis CAF-1 mutants and preferred maternal transmission reveals a more efficient reprogramming of epigenetic information in the male than the female germline.

• Keywords
• Arabidopsis thaliana, CAF-1, Chromatin, DNA methylation, Development, epigenetics, histone,
• MeSH
• Alleles MeSH
• Arabidopsis genetics   MeSH
• Epigenesis, Genetic * MeSH
• Phenotype MeSH
• Stress, Physiological genetics   MeSH
• Gene Ontology MeSH
• DNA Methylation genetics   MeSH
• Mutation genetics   MeSH
• Plant Infertility MeSH
• Arabidopsis Proteins genetics   metabolism   MeSH
• Gene Expression Regulation, Plant MeSH
• Base Sequence MeSH
• Seeds embryology   MeSH
• RNA Splicing Factors genetics   metabolism   MeSH
• Transcriptome genetics   MeSH
• Inheritance Patterns genetics   MeSH
• Ovule embryology   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• At2g20020 protein, Arabidopsis MeSH Browser
• FAS protein, Arabidopsis MeSH Browser
• Arabidopsis Proteins MeSH
• RNA Splicing Factors MeSH

Seed production is facing a three-fold challenge: ensuring food security, maintaining sustainability, and adapting to climate change. Although most efforts have focused on genetic breeding and crop management, additional levers need to be explored to optimize plant tolerance to the accelerating climate change. A groundbreaking approach will be to capitalize on the ability of plants to naturally adjust their responses to fluctuating environments during the crop cycle and transmit stress-induced information to the next generation(s). This viewpoint aims at highlighting the potential application of maternal stress memory as a priming strategy to produce primed seedlots. This requires identifying the priming conditions among stress memory scenarios, defined according to the starting point of the new generation within the plant, that is, the fertilization. If the contribution of stress-induced epigenetic-associated mechanisms in inheritance patterns to promote germination and early growth development has been evidenced, the whole picture is not fully understood. Further investigations are required to characterize the maternally inherited plant stress imprints leading to higher stress tolerance of seedlots. Detailed characterization of the mechanisms of stress-induced maternally heritable seed traits could provide novel targets for the seed industry and open new avenues to deploy the potential of maternal stress memory for enhancing seed performances.

• Keywords
• acclimation, epigenetics, germination, intra/inter/transgenerational memory, maternal, seed priming, seeds, stress memory,
• MeSH
• Epigenesis, Genetic * MeSH
• Stress, Physiological MeSH
• Germination genetics   MeSH
• Climate Change MeSH
• Seeds * genetics   physiology   growth & development   MeSH
• Plant Breeding MeSH
• Crops, Agricultural * genetics   physiology   growth & development   MeSH
• Publication type
• Journal Article MeSH

McKusick's database MIM has grown since its early beginning in sixties to 1985 when the online version (OMIM) appeared. The last edition of three volumes was printed in 1998. It has become a very valuable tool for all geneticists, and also clinicians of other disciplines started using it as a source of important information. The original limitation to disorders with mendelian inheritance has been step by step broken down, all components of human genome and also genes without known function and their epigenetic changes have been included. It was a pleasure for all of us to congratulate to McKusick's honorary degree obtained this year by the oldest European university in Bologna (with a short biography).

• MeSH
• Databases, Genetic history   MeSH
• Heredity MeSH
• History, 20th Century MeSH
• Genetics, Medical history   MeSH
• Check Tag
• History, 20th Century MeSH
• Publication type
• English Abstract MeSH
• Biography MeSH
• Journal Article MeSH
• Historical Article MeSH

• About
• McCusick, Victor Almon

Although epigenetic modifications have been intensely investigated over the last decade due to their role in crop adaptation to rapid climate change, it is unclear which epigenetic changes are heritable and therefore transmitted to their progeny. The identification of epigenetic marks that are transmitted to the next generations is of primary importance for their use in breeding and for the development of new cultivars with a broad-spectrum of tolerance/resistance to abiotic and biotic stresses. In this review, we discuss general aspects of plant responses to environmental stresses and provide an overview of recent findings on the role of transgenerational epigenetic modifications in crops. In addition, we take the opportunity to describe the aims of EPI-CATCH, an international COST action consortium composed by researchers from 28 countries. The aim of this COST action launched in 2020 is: (1) to define standardized pipelines and methods used in the study of epigenetic mechanisms in plants, (2) update, share, and exchange findings in epigenetic responses to environmental stresses in plants, (3) develop new concepts and frontiers in plant epigenetics and epigenomics, (4) enhance dissemination, communication, and transfer of knowledge in plant epigenetics and epigenomics.

• Keywords
• abiotic stress, biotic stress, epigenetic, methodology, stress memory, transgenerational memory,
• MeSH
• Acclimatization genetics   MeSH
• Epigenesis, Genetic MeSH
• Epigenomics methods   MeSH
• Adaptation, Physiological genetics   MeSH
• Stress, Physiological genetics   MeSH
• DNA Methylation MeSH
• Gene Expression Regulation, Plant MeSH
• Plant Breeding methods   MeSH
• Inheritance Patterns MeSH
• Crops, Agricultural genetics   MeSH
• Publication type
• Journal Article MeSH
• Review MeSH

Epigenetic variation has been proposed to contribute to the success of asexual plants, either as a contributor to phenotypic plasticity or by enabling transient adaptation via selection on transgenerationally stable, but reversible, epialleles. While recent studies in experimental plant populations have shown the potential for epigenetic mechanisms to contribute to adaptive phenotypes, it remains unknown whether heritable variation in ecologically relevant traits is at least partially epigenetically determined in natural populations. Here, we tested the hypothesis that DNA methylation variation contributes to heritable differences in flowering time within a single widespread apomictic clonal lineage of the common dandelion (Taraxacum officinale s. lat.). Apomictic clone members of the same apomictic lineage collected from different field sites showed heritable differences in flowering time, which was correlated with inherited differences in methylation-sensitive AFLP marker profiles. Differences in flowering between apomictic clone members were significantly reduced after in vivo demethylation using the DNA methyltransferase inhibitor zebularine. This synchronization of flowering times suggests that flowering time divergence within an apomictic lineage was mediated by differences in DNA methylation. While the underlying basis of the methylation polymorphism at functional flowering time-affecting loci remains to be demonstrated, our study shows that epigenetic variation contributes to heritable phenotypic divergence in ecologically relevant traits in natural plant populations. This result also suggests that epigenetic mechanisms can facilitate adaptive divergence within genetically uniform asexual lineages.

• Keywords
• DNA methylation *, adaptation *, apomixis *, asexual reproduction *, epigenetic inheritance *,
• MeSH
• Amplified Fragment Length Polymorphism Analysis MeSH
• Epigenesis, Genetic * MeSH
• Flowers physiology   MeSH
• DNA Methylation * MeSH
• Microsatellite Repeats MeSH
• Reproduction, Asexual MeSH
• Genetics, Population MeSH
• Taraxacum genetics   physiology   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Czech Republic MeSH
• Finland MeSH
• Germany MeSH

Phenotypic diversification within pathogen populations can enhance survival in stressful environments, broaden niche colonization, and expand the ecological range of infectious diseases due to emerging collective pathogenicity characteristics. We describe a gene regulatory network property in the opportunistic pathogen Pseudomonas aeruginosa that generates diversity of gene expression and pathogenicity behavior at the single-cell level and that is stabilized by epigenetic cellular memory. The resulting heterogeneity in the expression of the glpD gene-an indicator of host-derived glycerol metabolism and intra-host presence-shapes adaptive processes that are subject to natural selection. Our work on how epigenetics generates phenotypic variation in response to the environment and how these changes are inherited to the next generation provides insights into phenotypic diversity and the emergence of unique functionalities at higher levels of organization. These could be crucial for controlling infectious disease outcomes.

• Keywords
• GlpD, Pseudomonas aeruginosa, epigenetic memory, glycerol metabolism, single-cell,
• MeSH
• Bacterial Proteins genetics   metabolism   MeSH
• Epigenetic Memory MeSH
• Epigenesis, Genetic * MeSH
• Phenotype MeSH
• Gene Regulatory Networks MeSH
• Host-Pathogen Interactions * genetics   MeSH
• Pseudomonas Infections microbiology   MeSH
• Pseudomonas aeruginosa * genetics   pathogenicity   MeSH
• Gene Expression Regulation, Bacterial MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Bacterial Proteins MeSH

Male infertility is a worldwide problem associated with genetic background, environmental factors, and diseases. One of the suspected contributing factors to male infertility is diabetes mellitus. We investigated the molecular and morphological changes in sperms and testicular tissue of diabetic males. The study was performed in streptozotocin-induced type 1 diabetes mouse model. Diabetes decreased sperm concentration and viability and increased sperm apoptosis. Changes in protamine 1/protamine 2 ratio indicated reduced sperm quality. The testicular tissue of diabetic males showed significant tissue damage, disruption of meiotic progression, and changes in the expression of genes encoding proteins important for spermiogenesis. Paternal diabetes altered sperm quality and expression pattern in the testes in offspring of two subsequent generations. Our study revealed that paternal diabetes increased susceptibility to infertility in offspring through gametic alternations. Our data also provide a mechanistic basis for transgenerational inheritance of diabetes-associated pathologies since protamines may be involved in epigenetic regulations.

• MeSH
• Biomarkers MeSH
• Diabetes Mellitus, Type 1 complications   metabolism   MeSH
• Phenotype MeSH
• Genetic Predisposition to Disease * MeSH
• Meiosis MeSH
• Infertility, Male etiology   MeSH
• Mice MeSH
• Protamines metabolism   MeSH
• Spermatogenesis MeSH
• Spermatozoa metabolism   MeSH
• Testis metabolism   MeSH
• Inheritance Patterns * MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Mice MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Biomarkers MeSH
• Protamines MeSH

Uniparental silencing of 35S rRNA genes (rDNA), known as nucleolar dominance (ND), is common in interspecific hybrids. Allotetraploid Tragopogon mirus composed of Tragopogon dubius (d) and Tragopogon porrifolius (p) genomes shows highly variable ND. To examine the molecular basis of such variation, we studied the genetic and epigenetic features of rDNA homeologs in several lines derived from recently and independently formed natural populations. Inbred lines derived from T. mirus with a dominant d-rDNA homeolog transmitted this expression pattern over generations, which may explain why it is prevalent among natural populations. In contrast, lines derived from the p-rDNA dominant progenitor were meiotically unstable, frequently switching to co-dominance. Interpopulation crosses between progenitors displaying reciprocal ND resulted in d-rDNA dominance, indicating immediate suppression of p-homeologs in F1 hybrids. Original p-rDNA dominance was not restored in later generations, even in those segregants that inherited the corresponding parental rDNA genotype, thus indicating the generation of additional p-rDNA and d-rDNA epigenetic variants. Despite preserved intergenic spacer (IGS) structure, they showed altered cytosine methylation and chromatin condensation patterns, and a correlation between expression, hypomethylation of RNA Pol I promoters and chromatin decondensation was apparent. Reversion of such epigenetic variants occurred rarely, resulting in co-dominance maintained in individuals with distinct genotypes. Generally, interpopulation crosses may generate epialleles that are not present in natural populations, underlying epigenetic dynamics in young allopolyploids. We hypothesize that highly expressed variants with distinct IGS features may induce heritable epigenetic reprogramming of the partner rDNA arrays, harmonizing the expression of thousands of genes in allopolyploids.

• Keywords
• Tragopogon mirus, allopolyploid, chromatin modification, epigenetic variants, interpopulation hybridization, nucleolar dominance, ribosomal DNA,
• MeSH
• DNA, Plant genetics   MeSH
• Epigenomics * MeSH
• Phenotype MeSH
• Genome, Plant genetics   MeSH
• Genotype MeSH
• Hybridization, Genetic MeSH
• DNA Methylation MeSH
• Evolution, Molecular * MeSH
• Polyploidy MeSH
• Gene Expression Regulation, Plant * MeSH
• DNA, Ribosomal genetics   MeSH
• Tragopogon genetics   MeSH
• Gene Silencing MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• DNA, Plant MeSH
• DNA, Ribosomal MeSH