DNA Methylation: A Mechanism for Embedding Early Life Experiences in the Genome

Although epidemiological data provide evidence that early life experience plays a critical role in human development, the mechanism of how this works remains in question. Recent data from human and animal literature suggest that epigenetic changes, such as DNA methylation, are involved not only in cellular differentiation but also in the modulation of genome function in response to early life experience affecting gene function and the phenotype. Such modulations may serve as a mechanism for life‐long genome adaptation. These changes seem to be widely distributed across the genome and to involve central and peripheral systems. Examining the environmental circumstances associated with the onset and reversal of DNA methylation will be critical for understanding risk and resiliency.     

DNA methylation polymorphism in flue-cured tobacco and candidate markers for tobacco mosaic virus resistance

DNA methylation plays an important role in the epigenetic regulation of gene expression during plant growth, development, and polyploidization. However, there is still no distinct evidence in tobacco regarding the distribution of the methylation pattern and whether it contributes to qualitative characteristics. We studied the levels and patterns of methylation polymorphism at CCGG sites in 48 accessions of allotetraploid flue-cured tobacco, Nicotiana tabacum, using a methylation-sensitive amplified polymorphism (MSAP) technique. The results showed that methylation existed at a high level among tobacco accessions, among which 49.3% sites were methylated and 69.9% allelic sites were polymorphic. A cluster analysis revealed distinct patterns of geography-specific groups. In addition, three polymorphic sites significantly related to tobacco mosaic virus (TMV) resistance were explored. This suggests that tobacco breeders should pay more attention to epigenetic traits.     

甲醛、组蛋白（脱）甲基化与学习记忆

组蛋白的甲基化与脱甲基是调控DNA特定基因“开”与“关”的主要分子机制之一,与哺乳动物表观遗传密切相关。研究表明,组蛋白的可逆共价修饰,也是记忆与遗忘的分子调控机制。甲醛作为甲基化供体,参与了组蛋白修饰的关键环节。因此,甲醛代谢失调,可能影响组蛋白甲基化与脱甲基,也影响DNA甲基化与脱甲基,这可能是老年认知损伤的因素之一。     

Epigenetic Vestiges of Early Developmental Adversity: Childhood Stress Exposure and DNA Methylation in Adolescence

Fifteen‐year‐old adolescents (N = 109) in a longitudinal study of child development were recruited to examine differences in DNA methylation in relation to parent reports of adversity during the adolescents’ infancy and preschool periods. Microarray technology applied to 28,000 cytosine–guanine dinucleotide sites within DNA derived from buccal epithelial cells showed differential methylation among adolescents whose parents reported high levels of stress during their children’s early lives. Maternal stressors in infancy and paternal stressors in the preschool years were most strongly predictive of differential methylation, and the patterning of such epigenetic marks varied by children’s gender. To the authors’ knowledge, this is the first report of prospective associations between adversities in early childhood and the epigenetic conformation of adolescents’ genomic DNA.     

Individual Differences in Childhood Behavior Disorders Associated With Epigenetic Modulation of the Cortisol Receptor Gene

Behavioral/emotional difficulties in children are the first sign of mental health problems. These problems are however, heterogeneous. A domain that may identify homogenous subgroups is hypothalamic–pituitary–adrenal function. This study tested whether epigenetic regulation of glucocorticoid receptor gene could explain the co‐occurrence of anxiety problems in children with behavior problems. Four‐ to 16‐year‐old clinically referred children (N = 241) were measured for psychiatric symptoms, methylation of target CpG sites in blood or saliva, and morning cortisol levels in those who gave blood. Increased methylation of promoter 1F CpG sites was associated with higher vulnerability to co‐occurring internalizing symptoms and morning cortisol. The results support increasing optimism that epigenetic regulation of key neuroendocrine systems might help explain hitherto unfathomable individual differences in susceptibility to psychiatric symptom profiles.     

Integrated metabolism and epigenetic modifications in the macrophages of mice in responses to cold stress

The negative effects of low temperature can readily induce a variety of diseases. We sought to understand the reasons why cold stress induces disease by studying the mechanisms of fine-tuning in macrophages following cold exposure. We found that cold stress triggers increased macrophage activation accompanied by metabolic reprogramming of aerobic glycolysis. The discovery, by genome-wide RNA sequencing, of defective mitochondria in mice macrophages following cold exposure indicated that mitochondrial defects may contribute to this process. In addition, changes in metabolism drive the differentiation of macrophages by affecting histone modifications. Finally, we showed that histone acetylation and lactylation are modulators of macrophage differentiation following cold exposure. Collectively, metabolism-related epigenetic modifications are essential for the differentiation of macrophages in cold-stressed mice, and the regulation of metabolism may be crucial for alleviating the harm induced by cold stress.     

Processes and stages of differentiation in European higher education

In this article we discuss processes of internal differentiation that have characterised European higher education systems in the last 50 years. We argue that these processes have gone through two main stages and in two different directions, each of which is showing its limits in the long run. Therefore, we expect a third stage of differentiation, which will be both internal to individual higher education institutions and multi‐dimensional concerning functions performed. In the first stage (1960–1970s) the main objective was to create a vocational track, without having to profoundly modify traditional academic institutions. In the second stage (mid‐1990s) the main objective was to differentiate between the more and the less competitive universities as regards the amount of financial and symbolic resources provided to them. However, large comprehensive universities are containers of smaller units whose performance may vary widely. Moreover, research is just one of the several functions that modern universities perform. The final section of the article provides some empirical evidence from United Kingdom universities to support the hypothesis of a third stage of differentiation.     

Sibling differentiation in adolescence: implications for behavioral genetic theory

The presence of sibling "differentiating processes"--defined as processes in which increased sibling similarity in environmental or genetic factors leads to differences in sibling outcomes-poses a challenge for standard behavioral genetic theory and research. The presence of differentiation processes may affect estimates of genetic and environmental parameters in ways that have not been fully recognized. Utilizing data from the Nonshared Environment and Adolescent Development project, this study examined whether differentiating processes existed for seven composite indices of positive and negative adolescent adjustment. The 720 sibling pairs in the study were broken down into groups by age difference (0-4 years) between siblings. The hypothesis that siblings close in age would demonstrate lower correlations on adjustment measures was generally supported at two time points, three years apart. However, siblings one year apart at Time 1 were more similar to each other than were siblings two years apart, suggesting that shared environmental influences counteract sibling differentiation processes for these siblings. The overall trend supporting sibling differentiation was found to be unrelated to measures of sibling positivity and negativity.     

New Study Programs and Specializations: The Effect of Governmental Funding and Paradigmatic Development

Studies on the emergence of scientific fields and disciplines produce a number of factors influencing these processes. The present study investigates whether these factors are also relevant in the teaching domain: the emergence of new study programs and specializations within programs. The classification of internal and external factors is applied to such processes of programmatic differentiation. Drawing on social exchange and resource dependency theory, the effects of the governmental funding mechanism of educational provisions (an external factor) and the level of paradigmatic development (an internal factor) are analyzed, using a large data set on processes of differentiation in the Dutch university sector between 1974 and 1993. The two factors proved to be relevant in explaining the emergence of new programs and specializations. In the final section some anomalies and suggestions for further research are discussed.     

Differentiation: a contested concept

The purpose of this article is to examine the notion of differentiation, which in recent years has become a key word in inspectors’ reports and other official documents. It is argued that the dominant definition of differentiation undermines attempts to relate the curriculum to the individual by emphasising variations in teaching approaches, but neglecting the role of the whole curriculum. The concept of the individual underpinning differentiation processes is identified as a significant issue. As opposed to the psychometric and behavioural notions of individual differences and competencies which have been influential, an alternative conception of the individual as a socially constituted knowing subject is proposed. In exploring the implications of this for the curriculum, it is suggested that the differentiation of educational knowledge in the National Curriculum is problematical, because it leads to the construction of a curriculum which fails to make connections with pupils’ experiences and common‐sense understandings of the world and thus engage them in educational processes     

Evolutionary developmental psychology

Evolutionary developmental psychology is the study of the genetic and ecological mechanisms that govern the development of social and cognitive competencies common to all human beings and the epigenetic (gene-environment interactions) processes that adapt these competencies to local conditions. The basic assumptions and domains of this emerging field, as related to human life history and social and cognitive development, are outlined, as are implications for issues of importance in contemporary society.     

Perceptions of leadership characteristics by gifted elementary students

This article presents questioning strategies that can be used by a teacher, parent, or museum guide when introducing gifted children to the art museum. The strategies utilize eight creative processes and seventeen content, process and product modifications, based on the differentiation models of Frank Williams and June Maker. A single work of art is used and examples of questions employing these differentiation techniques are given.     

Normal epigenetic inheritance in mice conceived by in vitro fertilization and embryo transfer

An association between assisted reproductive technology (ART) and neurobehavioral imprinting disorders has been reported in many studies, and it seems that ART may interfere with imprint reprogramming. However, it has never been explored whether epigenetic errors or imprinting disease susceptibility induced by ART can be inherited transgenerationally. Hence, the aim of this study was to determine the effect of in vitro fertilization and embryo transfer (IVF-ET) on transgenerational inheritance in an inbred mouse model. Mice derived from IVF-ET were outcrossed to wild-type C57BL/6J to obtain their female and male line F2 and F3 generations. Their behavior, morphology, histology, and DNA methylation status at several important differentially methylated regions (DMRs) were analyzed by Morris water maze, hematoxylin and eosin (H&E) staining, and bisulfite genomic sequencing. No significant differences in spatial learning or phenotypic abnormality were found in adults derived from IVF (F1) and female and male line F2 and F3 generations. A borderline trend of hypomethylation was found in H19 DMR CpG island 3 in the female line-derived F3 generation (0.40±0.118, P=0.086). Methylation status in H19/Igf2 DMR island 1, Igf2 DMR, KvDMR, and Snrpn DMR displayed normal patterns. Methylation percentage did not differ significantly from that of adults conceived naturally, and the expression of the genes they regulated was not disturbed. Transgenerational integrity, such as behavior, morphology, histology, and DNA methylation status, was maintained in these generations, which indicates that exposure of female germ cells to hormonal stimulation and gamete manipulation might not affect the individuals and their descendents.     

云南四倍体多星韭二倍体化的细胞学研究

采用常规制片技术,对苍山、鸡足山华严寺和昆明长虫山3个四倍体多星韭种群进行了减数分裂观察和核型分析.结果表明：核型分析反映出云南西北部地区的苍山、鸡足山四倍体多星韭的核型对称性比中部地区昆明长虫山种群高;减数分裂观察表明四倍体多星韭的28条染色体在减数分裂前期I时,两两联会成为14个二价体,后期I配对的染色体分离比较同步,没有观察到提前或延后分离以及染色体桥或染色体片段;对四倍体减数分裂过程的观察支持核型分析将28条染色体成2地配成14组,而不是成4地配成7组的结果,为四倍体多星韭的二倍体化提供了直接的细胞学证据.     

Exploratory Mediation Analysis with Many Potential Mediators

Social and behavioral scientists are increasingly employing technologies such as fMRI, smartphones, and gene sequencing, which yield ‘high-dimensional’ datasets with more columns than rows. There is increasing interest, but little substantive theory, in the role the variables in these data play in known processes.

This necessitates exploratory mediation analysis, for which structural equation modeling is the benchmark method. However, this method cannot perform mediation analysis with more variables than observations. One option is to run a series of univariate mediation models, which incorrectly assumes independence of the mediators. Another option is regularization, but the available implementations may lead to high false-positive rates.

In this article, we develop a hybrid approach which uses components of both filter and regularization: the ‘Coordinate-wise Mediation Filter’. It performs filtering conditional on the other selected mediators. We show through simulation that it improves performance over existing methods. Finally, we provide an empirical example, showing how our method may be used for epigenetic research.     

Choice paths in the Swedish upper secondary education – a critical discourse analysis of recent reforms

Decentralisation policy in Sweden emphasises school capitation allowance, the local upper secondary schools’ decision‐making and pupils’ choices in contrast to previous bureaucratic governing. The aim of this article is to discuss how pupils’ educational choice paths are a part of the different kinds of integration and differentiation processes within upper secondary education. By doing so, the intention is to make a theoretical contribution to the ongoing discussion in this research field. In the light of Habermas’s theory of communicative action combined with Fairclough’s critical discourse analysis, educational choice paths have been studied as a process within three educational practices in a local quasi‐market in Sweden: (1) choice of upper secondary school, (2) choice of upper secondary programme, and (3) choice of courses and subjects within a programme. Some of the results demonstrate that pupils’ choice paths can be vocation‐oriented, career‐oriented and consumption‐oriented. It is argued that these different types of choice paths are related to a market discourse. Other results demonstrate that pupils’ group‐oriented, interest‐oriented and tradition‐oriented choice paths are built upon an active citizenship discourse, which is about creating meaning in terms of seeking knowledge and establishing social relations in upper secondary education. The analysis of these two paramount discourses indicates that pupils’ integration and differentiation processes are ambiguous.     

被子植物雌、雄配子体发育的研究

被子植物雌、雄配子体的形成是世代交替的关键过程之一。雌配子体的形成可以划分为两个连续的过程,即孢子发生和雌配子体发生。雄配子的形成则包括生殖细胞和营养细胞的分化,以及雄配子体的发生。同时,雌雄配子体发育的过程中还受到先关的调控确保了配子体的正常发育,阐述了被子植物雌雄配子体的发育过程及相关的调控,并综述了这一领域最新研究进展。     

Differentiating between and synthesizing quantitative,qualitative, and longitudinal research on polarized school cultures: a comment on Van Houtte (2006)

Van Houtte provides a valuable large‐sample quantitative analysis of differentiation and polarization processes between and within school cultures in Belgium. Such research across 34 secondary schools provides greater confidence that the findings in the ethnographic tradition for the differentiation–polarization theory are not due to idiosyncracies of the individual schools chosen. However, it is unhelpful to contrast her large‐sample approach with the ethnographic tradition by characterizing the former as quantitative and the latter as qualitative. Many ethnographic studies of secondary schools have employed quantitative methods. It is better to characterize her research as multi‐site and the ethnographic tradition as case‐study. This illuminates how the two methodologies can be more constructively synthesized. Within large sample multi‐site approaches some selection of in‐depth case studies, together with longitudinal data analysis, are needed to disentangle socio‐economic class effects from differentiation effects in order to determine causality.     

Representation of the cell and its processes in high school students: An integrated view

This paper presents an integrated view of the ideas and conceptual problems of high school students with respect to the cell, its processes, structure and relation to the functions of multicellular organisms. The theme of cell has divided into eight topics, with a questionnaire for each topic. In these topics, different levels of representation and understanding are distinguished between general considerations about plants and animals, those connected with processes at organ and system levels and, finally, the level of cell processes. Data from 1200 students were analysed. Results show that students have an analogical mechanism that establishes an isomorphism between the representation of the functioning of multicellular organisms of cell processes. A series of problems in understanding was also shown. Results imply that these problems are mainly due to students' lack of differentiation between some processes at organism and organ level, and have important implications for learning this subject. Finally, some suggestions are made for teaching.