SCARECROW is deployed in distinct developmental contexts during rice and maize leaf development

The flexible deployment of developmental regulators is an increasingly appreciated aspect of plant development and evolution. The GRAS transcription factor SCARECROW (SCR) regulates the development of the endodermis in Arabidopsis and maize roots, but during leaf development it regulates the development of distinct cell-types; bundle-sheath in Arabidopsis and mesophyll in maize. In rice, SCR is implicated in stomatal patterning, but it is unknown whether this function is additional to a role in inner leaf patterning. Here, we demonstrate that two duplicated SCR genes function redundantly in rice. Contrary to previous reports, we show that these genes are necessary for stomatal development, with stomata virtually absent from leaves that are initiated after germination of mutants. The stomatal regulator OsMUTE is down-regulated in Osscr1;Osscr2 mutants indicating that OsSCR acts early in stomatal development. Notably, Osscr1;Osscr2 mutants do not exhibit the inner leaf patterning perturbations seen in Zmscr1;Zmscr1h mutants and Zmscr1;Zmscr1h mutants do not exhibit major perturbations in stomatal patterning. Taken together, these results indicate that SCR was deployed in different developmental contexts after the divergence of rice and maize around 50 million years ago.

The Influence of Developmental Contexts in Adolescent’s Expected Sociopolitical Participation through the Sense of Unity: An Analysis of the Mediation Model Invariance through Sex, Age, and Socioeconomic Status

Civic engagement plays a positive role in adolescent wellbeing, as well as being the basis for maintaining a democratic society. This research analyzed how perceived support from developmental contexts contributes to adolescent civic engagement –assessed through their expectations of future sociopolitical participation–, mediated by sense of unity, and differences according to sex, age, and socioeconomic status. The sample included 3,715 participants (13–18 years old) from the 2019 OPINA Barometer who were selected using multistage random sampling stratified by conglomerates. The measures assessed sex, age, family, friends, classmates, and teacher support, the expectations of future sociopolitical participation, and sense of unity. Socioeconomic status was assessed by the Family Affluence Scale (FAS). Data analysis was conducted using descriptive statistics, mean comparisons, and structural equation models using bootstrapping and measurement invariance. Results showed developmental contexts to significantly affect expected sociopolitical participation only through the mediator role of the sense of unity. In addition, peer support (both friends and classmates) showed a stronger direct influence on sense of unity –and indirect influence on the expectations of future sociopolitical participation– than family and teachers. The model was invariant across sex, age, and FAS. This research highlights that a sense of unity, derived from feeling part of a larger dependable structure, is crucial for establishing behaviors in the interest of the common good, and that this social connectedness is learned in the most immediate developmental contexts, specifically, that of peers.

Women and Colonialism in Zambia

This paper focuses on the status of women in Zambia during pre-colonial, colonial and post-colonial periods. It highlights how colonialism perpetuated gender imbalances in Zambia and it examines the resilience of women’s leadership in different developmental contexts.

Doublesex mediates species-, sex-, environment- and trait-specific exaggeration of size and shape

Context-dependent trait exaggeration is a major contributor to phenotypic diversity. However, the genetic modifiers instructing development across multiple contexts remain largely unknown. We use the arthropod tibia, a hotspot for segmental differentiation, as a paradigm to assess the developmental mechanisms underlying the context-dependent structural exaggeration of size and shape through nutritional plasticity, sexual dimorphism and segmental differentiation. Using an RNAseq approach in the sexually dimorphic and male-polyphenic dung beetle Digitonthophagus gazella , we find that only a small portion (3.7%) of all transcripts covary positively in expression level with trait size across contexts. However, RNAi-mediated knockdown of the conserved sex-determination gene doublesex suggests that it functions as a context-dependent master mediator of trait exaggeration in D. gazella as well as the closely related dung beetle Onthophagus taurus . Taken together, our findings suggest (i) that the gene networks associated with trait exaggeration are highly dependent on the precise developmental context, (ii) that doublesex differentially shapes morphological exaggeration depending on developmental contexts and (iii) that this context-specificity of dsx -mediated trait exaggeration may diversify rapidly. This mechanism may contribute to the resolution of conflict arising from environment-dependent antagonistic selection among sexes and divergent developmental contexts in a wide range of animals.

Public data sources for regulatory genomic features

High-throughput technologies have led to a continuously growing amount of information about regulatory features in the genome. A wealth of data generated by large international research consortia is available from online databases. Disease-driven studies provide details on specific DNA elements or epigenetic modifications regulating gene expression in specific cellular and developmental contexts, but these results are usually only published in scientific articles. All this information can be helpful in interpreting variants in the regulatory genome. This review describes a selection of high-profile data sources providing information on the non-coding genome, as well as pitfalls and techniques to search and capture information from the literature.

A novel system for classifying tooth root phenotypes

Human root and canal number and morphology are highly variable, and internal root canal form and count does not necessarily co-vary directly with external morphology. While several typologies and classifications have been developed to address individual components of teeth, there is a need for a comprehensive system, that captures internal and external root features across all teeth. Using CT scans, the external and internal root morphologies of a global sample of humans are analysed (n=945). From this analysis a method of classification that captures external and internal root morphology in a way that is intuitive, reproducible, and defines the human phenotypic set is developed. Results provide a robust definition of modern human tooth root phenotypic diversity. Our method is modular in nature, allowing for incorporation of past and future classification systems. Additionally, it provides a basis for analysing hominin root morphology in evolutionary, ecological, genetic, and developmental contexts.

Dichaete, a Sox2 homologue, prevents activation of cell death in multiple developmental contexts

Precisely regulated cell death plays a critical role in normal development and is controlled by the balance of pro-apoptotic and anti-apoptotic signals. In Drosophila, transcription of the clustered cell death activators grim and reaper is turned on in the developing nervous system to eliminate neural stem cells at the end of embryonic development. This transcription is activated by a pulse of the Hox gene abdominal-A. We show here that the Sox2 homologue Dichaete inhibits neural stem cell death when overexpressed, and loss of Dichaete promotes premature neural stem cell death. The anti-apoptotic activity of Dichaete opposes the pro-apoptotic factors abdominal-A, as well as the transcription factor grainyhead. The function of all three genes impinge on an enhancer that regulates the transcription of grim and reaper. Furthermore, we find that the balance between abdominal-A and Dichaete is likely to regulate the death of other cells during development, including cells in the developing midline, the developing hindgut, and in the early abdominal epidermis. Loss of Dichaete results in premature death in these tissues. This death can be rescued by the deletion of the enhancer region between grim and reaper. These data suggest that Dichaete functions to inhibit cell death activated by abdominal-A in multiple developmental contexts.

Adolescent Substance Use

BACKGROUND Adolescent substance use has long been a global public health issue. In this study, we explored developmental contexts that correspond with protective and risk factors associated with adolescent substance use. The developmental contexts of interest are the family domain, the school domain, the peer domain, and the structured and unstructured leisure domains. The leisure domain is of particular interest as it often corresponds with protective and risk factors different from those associated with the other domains. The purpose of this study was to assess whether the identified domains are associated with adolescent alcohol use and cannabis use. METHODS This study used previously collected adolescent health and behavior surveillance data from (N = ~ 3,500) 7th-12th graders in a Northeastern state in the fall of 2019. The data was used to assess whether the identified domains are associated with adolescent alcohol use and cannabis use. We analyzed each outcome variable using separate hierarchical multiple regression models. RESULTS Each of the selected variables in our analysis: family, school, peer, structured and unstructured leisure domains were significantly associated with one or both of the dependent variables (alcohol or cannabis use). In our model, the peer domain was the strongest risk factor for adolescent substance use in our study, followed by the unstructured leisure domain. Family, structured leisure, and school offered similar levels of protection against substance use in per unit change. CONCLUSIONS Implications for utilizing the peer and leisure developmental contexts to prevent adolescent substance use and recommendations for further research and investment are discussed.