The construction of genetics teaching resources related to colour blindness and their application in genetics teaching

Red-green colour blindness is a classic example for the teaching of X-linked recessive inheritance in genetics course. However, there are lots of types of color vision deficiencies besides red-green colour blindness. Different color vision deficiencies caused by different genes may have different modes of inheritance. In recent years, many research achievements on colour blindness have been made. These achievements could be used as teaching resources in genetics course. Here, we summarize the construction of genetics teaching resources related to colour blindness and their application in genetics teaching in several chapters such as introduction, cellular and molecular basis of genetics, sex-linked inheritance, chromosomal aberration, gene mutation and advances in genetics. Teacher could use the resources in class or after class with different teaching methods such as questioning teaching method and task method. It may expand students' academic horizons and inspire students' interest in genetics besides grasping basic genetic knowledge.

Worldwide Well-Being: Simulated Twins Reveal Genetic and (Hidden) Environmental Influences

What are the major sources of worldwide variability in subjective well-being (SWB)? Twin and family studies of SWB have found substantial heritability and strong effects from unique environments but virtually no effects from shared environments. However, extant findings are not necessarily valid at the global level. Prior studies have examined within-countries variability but did not take into account mean differences across nations. In this article, we aim to estimate the effects of genetic factors, individual environmental exposures, and shared environments for the global population. We combine a set of knowns from national well-being studies (means and standard deviations) and behavioral-genetic studies (heritability) to model a scenario of twin studies across 157 countries. For each country, we simulate data for a set of twin pairs and pool the data into a global sample. We find a worldwide heritability of 31% to 32% for SWB. Individual environmental factors explain 46% to 52% of the variance (including measurement error), and shared environments account for 16% to 23% of the global variance in SWB. Worldwide, well-being is somewhat less heritable than within nations. In contrast to previous within-countries studies, we find a notable effect of shared environments. This effect is not limited to within families but operates at a national level.

The legacy of language: What we say, and what people hear, when we talk about genomics

The way we "talk" about genetics plays a vital role in whether public audiences feel at ease in having conversations about it. Our research explored whether there was any difference between "what we say" and "what people hear" when providing information about genetics to community groups who are known to be missing from genomics datasets. We conducted 16 focus groups with 100 members of the British public who had limited familiarity with genomics and self-identified as belonging to communities with Black African, Black Caribbean, and Pakistani ancestry as well as people of various ancestral heritage who came from disadvantaged socio-economic backgrounds. Participants were presented with spoken messages explaining genomics and their responses to these were analyzed. Results indicated that starting conversations that framed genomics through its potential benefits were met with cynicism and skepticism. Participants cited historical and present injustices as reasons for this as well as mistrust of private companies and the government. Instead, more productive conversations led with an acknowledgment that some people have questions-and valid concerns-about genomics, before introducing any of the details about the science. To diversify genomic datasets, we need to linguistically meet public audiences where they are at. Our research has demonstrated that everyday talk about genomics, used by researchers and clinicians alike, is received differently than it is likely intended. We may inadvertently be further disengaging the very audiences that diversity programs aim to reach.

Increasing the use of functional and multimodal genetic data in social science research

Genetic studies in the social sciences could be augmented through the additional consideration of functional (transcriptome, methylome, metabolome) and/or multimodal genetic data when attempting to understand the genetics of social phenomena. Understanding the biological pathways linking genetics and the environment will allow scientists to better evaluate the functional importance of polygenic scores.

Genes, genomes, and developmental process

The view advanced by Madole & Harden falls back on the dogma of a gene as a DNA sequence that codes for a fixed product with an invariant function regardless of temporal and spatial contexts. This outdated perspective entrenches the metaphor of genes as static units of information and glosses over developmental complexities.

Meeting counterfactual causality criteria is not the problem

Counterfactual causal interpretations of family genetic effects are appropriate, but neglect an important feature: Provision of unique information about expected outcomes following an independent decision, such as a decision to intervene. Counterfactual causality criteria are unlikely to resolve controversies about behavioral genetic findings; such controversies are likely to continue until counterfactual inferences are translated into interventional hypotheses and designs.

Genetics can inform causation, but the concepts and language we use matters

Madole & Harden describe how genetics can be used in a causal framework. We agree with many of their opinions but argue that comparing within-family designs to experiments is unnecessary and that the proposed influence of genetics on behavior can be better described as inus conditions.

Comparative neurogenetics of dog behavior complements efforts towards human neuropsychiatric genetics

Domestic dogs display a wide array of heritable behaviors that have intermediate genetic complexity thanks to a long history of human-influenced selection. Comparative genetics in dogs could address the scarcity of non-human neurogenetic systems relevant to human neuropsychiatric disorders, which are characterized by mental, emotional, and behavioral symptoms and involve vastly complex genetic and non-genetic risk factors. Our review describes the diverse behavioral "phenome" of domestic dogs, past and ongoing sources of behavioral selection, and the state of canine behavioral genetics. We highlight two naturally disordered behavioral domains that illustrate how dogs may prove useful as a comparative, forward neurogenetic system: canine age-related cognitive dysfunction, which can be examined more rapidly given the attenuated lifespan of dogs, and compulsive disorders, which may have genetic roots in purpose-bred behaviors. Growing community science initiatives aimed at the companion dog population will be well suited to investigating such complex behavioral phenotypes and offer a comparative resource that parallels human genomic initiatives in scale and dimensionality.

The Russian Backdrop to Dobzhansky's Genetics and the Origin of Species

Theodosius Dobzhansky was one of the principal 'founding fathers' of the modern 'synthetic theory of evolution' and the 'biological species' concept, first set forth in his classic book, Genetics and the Origin of Species (1937). Much of the discussion of Dobzhansky's work by historians has focused on English-accessible sources, and has emphasized the roles of the Morgan School, and figures such as Sewall Wright, and Leslie C. Dunn. This article uses Dobzhansky's Russian articles that are unknown to English-speaking readers, and his late 1920s to early 1930s correspondence with colleagues and friends in the Soviet Union, to clarify some of the Russian influences on Dobzhansky's evolving evolutionary views, particularly the development of his views on species and speciation. For Dobzhansky, as for Darwin, the problem of species and speciation was crucial for his theoretical explanation of evolution.

Johann Gregor Mendel: the victory of statistics over human imagination

In 2022, we celebrated 200 years since the birth of Johann Gregor Mendel. Although his contributions to science went unrecognized during his lifetime, Mendel not only described the principles of monogenic inheritance but also pioneered the modern way of doing science based on precise experimental data acquisition and evaluation. Novel statistical and algorithmic approaches are now at the center of scientific work, showing that work that is considered marginal in one era can become a mainstream research approach in the next era. The onset of data-driven science caused a shift from hypothesis-testing to hypothesis-generating approaches in science. Mendel is remembered here as a promoter of this approach, and the benefits of big data and statistical approaches are discussed.

Gregor Mendel and the theory of species multiplication

According to the revisionist interpretation of Mendel's pea crosses, his primary aim was not to study the inheritance of traits. Instead, he was interested in the question raised by Linnaeus as to whether new species could arise from the hybridization of existing species. The genetic interpretation is therefore seen as ahistorical by the revisionists. This view goes back to the 1979 article "Mendel no Mendelian?" by the historian of science R.C. Olby. A closer analysis shows that Olby implicitly assumed Mendel adhered to the unusual strictest species definition for Pisum. However, we argue that Mendel only mentions the hypothetical application of this strict definition in his 1866 paper. Like most of his contemporaries, Mendel accepted variation within species where the differences between varieties and species were a matter of degree. After researching variable hybrids in peas (Pisum; 1854-1863), Mendel also studied constant hybrids in hawkweeds (Hieracium; 1866-1873), which he considered to be new species. There is no debate about the latter, but the matter becomes muddled because Olby lumps Pisum and Hieracium together, despite their having completely different reproduction systems. Based on newly discovered historical sources, we also dispute several other assumptions made by Olby. We do not consider Olby's claim that Mendel conducted the Pisum experiments to investigate species multiplication to be tenable.

Daily Step Counts Before and After the COVID-19 Pandemic Among All of Us Research Participants

This cohort study of US adults examines changes in physical activity following the onset of the COVID-19 pandemic.

Mendel did not study common, naturally occurring phenotypes

Modern genetics research increasingly reveals that what is commonly termed Mendelian genetics occurs rarely in nature, especially with regard to the effects that genetic variation exerts on human characteristics. It has been argued that an inappropriate emphasis on Mendel's work could distort the public understanding of genetics and indeed in the UK Mendel has been completely dropped from the official school syllabus. There is a widespread misunderstanding that Mendel studied common phenotypes such as height and colour in individual pea plants. In fact, he studied a handful of specially selected phenotypes which he observed to be always dichotomous in 22 specially bred varieties of pea and studied crosses between individuals from these different varieties. This approach enabled him to study a small number of phenotypes which did in fact exhibit truly Mendelian transmission. Modern molecular genetic studies have now demonstrated that these phenotypes result from loss of function variants which result in markedly reduced activity of specific proteins and which hence have recessive effects. Understanding that Mendel studied the effects of loss of function mutations in crosses between artificially bred varieties, rather than naturally occurring variation in a population, could allow his work to continue to be taught as part of a modern genetics curriculum.

Speedy light focusing through scattering media by a cooperatively FPGA-parameterized genetic algorithm

We developed an accelerated Genetic Algorithm (GA) system based on the cooperation of a field-programmable gate array (FPGA) and the optimized parameters that enables fast light focusing through scattering media. Starting at the searching space, which influences the convergence of the optimization algorithms, we manipulated the mutation rate that defines the number of mutated pixels on the spatial light modulator to accelerate the GA process. We found that the enhanced decay ratio of the mutation rate leads to a much faster convergence of the GA. A convergence-efficiency function was defined to gauge the tradeoff between the processing time and the enhancement of the focal spot. This function allowed us to adopt the shorter iteration number of the GA that still achieves applicable light focusing. Furthermore, the accelerated GA configuration was programmed in FPGA to boost processing speed at the hardware level. It shows the ability to focus light through scattering media within a few seconds, 150 times faster than the PC-based GA. The processing cycle could be further promoted to a millisecond-level with the advanced FPGA processor chips. This study makes the evolution-based optimization approach adaptable in dynamic scattering media, showing the capability to tackle wavefront shaping in biological material.

Mendel’s legacy in modern genetics

A new collection of articles celebrating the bicentennial of Gregor Mendel’s birth discuss his life, work and legacy in modern-day genetic research

The deceptive simplicity of mendelian genetics

Gregor Mendel meticulously uncovered the genetic basis of heredity in work that transformed the science of biology. But does the alluring simplicity of Mendel’s laws sometimes obscure the true complexity of genetics?

Johann Gregor Mendel: Born to be a scientist?

Gregor Johann Mendel, born 200 years ago, was supposed to be a farmer, intended to be a teacher and became a priest, before becoming the researcher associated with genetics we know today. This Perspective looks at his life through his own words.

Kristine Bonnevie's theories on the genetics of fingerprints, and their application in Germany

This paper offers a historical reconstruction of the efforts to geneticize fingerprints, focusing on the theories put forward by the Norwegian biologist Kristine Bonnevie. The criminological and colonial roots of the preoccupation with fingerprints led to the creation of huge catalogues of fingerprints, which later became the starting point of Bonnevie's analysis. Building on insights she gained from her studies on the inheritance of human pathologies, Bonnevie insisted that all ten fingers exhibited varying manifestations of a single, underlying genotypic design. In 1923-4, she identified several theoretical genes that presumably constituted this hypothetical genotypic finger; five years later she revised her theory in light of a series of embryological dissections she conducted. Her new theory was adopted by German jurists, doctors and racial-anthropologists who relied on it to determine legal questions of disputed paternity. The extensive application of Bonnevie's genetic theory also exposed its deficiencies, and by the late 1950s her model was abandoned. At the same time, one of the most important genetic variables that Bonnevie discovered (or, invented) entered mainline genetic theory, and is still being used to this very day. The paper examines these developments, highlighting the multiple and complex relations between scientific theory building, practical considerations related to the gathering and processing of data, and social, racial and gender biases that shaped the process of "Mendelization" of finger print patterns.

Genetics and Epigenetics in Allergic Rhinitis

The pathogenesis of allergic rhinitis is associated with genetic, environmental, and epigenetic factors. Genotyping of single nucleotide polymorphisms (SNPs) is an advanced technique in the field of molecular genetics that is closely correlated with genome-wide association studies (GWASs) in large population groups with allergic diseases. Many recent studies have paid attention to the role of epigenetics, including alteration of DNA methylation, histone acetylation, and miRNA levels in the pathogenesis of allergic rhinitis. In this review article, genetics and epigenetics of allergic rhinitis, including information regarding functions and significance of previously known and newly-discovered genes, are summarized. Directions for future genetic and epigenetic studies of allergic rhinitis are also proposed.

The crucial role of genome-wide genetic variation in conservation

The unprecedented rate of extinction calls for efficient use of genetics to help conserve biodiversity. Several recent genomic and simulation-based studies have argued that the field of conservation biology has placed too much focus on conserving genome-wide genetic variation, and that the field should instead focus on managing the subset of functional genetic variation that is thought to affect fitness. Here, we critically evaluate the feasibility and likely benefits of this approach in conservation. We find that population genetics theory and empirical results show that conserving genome-wide genetic variation is generally the best approach to prevent inbreeding depression and loss of adaptive potential from driving populations toward extinction. Focusing conservation efforts on presumably functional genetic variation will only be feasible occasionally, often misleading, and counterproductive when prioritized over genome-wide genetic variation. Given the increasing rate of habitat loss and other environmental changes, failure to recognize the detrimental effects of lost genome-wide genetic variation on long-term population viability will only worsen the biodiversity crisis.

The gene: An appraisal

The gene can be described as the foundational concept of modern biology. As such, it has spilled over into daily discourse, yet it is acknowledged among biologists to be ill-defined. Here, following a short history of the gene, I analyse critically its role in inheritance, evolution, development, and morphogenesis. Wilhelm Johannsen's genotype-conception, formulated in 1910, has been adopted as the foundation stone of genetics, giving the gene a higher degree of prominence than is justified by the evidence. An analysis of the results of the Long-Term Evolution Experiment (LTEE) with E. coli bacteria, grown over 60,000 generations, does not support spontaneous gene mutation as the source of variance for natural selection. From this it follows that the gene is not Mendel's unit of inheritance: that must be Johannsen's transmission-conception at the gamete phenotype level, a form of inheritance that Johannsen did not consider. Alternatively, I contend that biology viewed on the bases of thermodynamics, complex system dynamics and self-organisation, provides a new framework for the foundations of biology. In this framework, the gene plays a passive role as a vital information store: it is the phenotype that plays the active role in inheritance, evolution, development, and morphogenesis.

Detection of Morphological Abnormalities in Schizophrenia: An Important Step to Identify Associated Genetic Disorders or Etiologic Subtypes

Current research suggests that alterations in neurodevelopmental processes, involving gene X environment interactions during key stages of brain development (prenatal period and adolescence), are a major risk for schizophrenia. First, epidemiological studies supporting a genetic contribution to schizophrenia are presented in this article, including family, twin, and adoption studies. Then, an extensive literature review on genetic disorders associated with schizophrenia is reviewed. These epidemiological findings and clinical observations led researchers to conduct studies on genetic associations in schizophrenia, and more specifically on genomics (CNV: copy-number variant, and SNP: single nucleotide polymorphism). The main structural (CNV) and sequence (SNP) variants found in individuals with schizophrenia are reported here. Evidence of genetic contributions to schizophrenia and current knowledge on genetic syndromes associated with this psychiatric disorder highlight the importance of a clinical genetic examination to detect minor physical anomalies in individuals with ultra-high risk of schizophrenia. Several dysmorphic features have been described in schizophrenia, especially in early onset schizophrenia, and can be viewed as neurodevelopmental markers of vulnerability. Early detection of individuals with neurodevelopmental abnormalities is a fundamental issue to develop prevention and diagnostic strategies, therapeutic intervention and follow-up, and to ascertain better the underlying mechanisms involved in the pathophysiology of schizophrenia.

The Simple Biology of Flipons and Condensates Enhances the Evolution of Complexity

The classical genetic code maps nucleotide triplets to amino acids. The associated sequence composition is complex, representing many elaborations during evolution of form and function. Other genomic elements code for the expression and processing of RNA transcripts. However, over 50% of the human genome consists of widely dispersed repetitive sequences. Among these are simple sequence repeats (SSRs), representing a class of flipons, that under physiological conditions, form alternative nucleic acid conformations such as Z-DNA, G4 quartets, I-motifs, and triplexes. Proteins that bind in a structure-specific manner enable the seeding of condensates with the potential to regulate a wide range of biological processes. SSRs also encode the low complexity peptide repeats to patch condensates together, increasing the number of combinations possible. In situations where SSRs are transcribed, SSR-specific, single-stranded binding proteins may further impact condensate formation. Jointly, flipons and patches speed evolution by enhancing the functionality of condensates. Here, the focus is on the selection of SSR flipons and peptide patches that solve for survival under a wide range of environmental contexts, generating complexity with simple parts.

Triangulating Evidence through the Inclusion of Genetically Informed Designs

Much research effort is invested in attempting to determine causal influences on disease onset and progression to inform prevention and treatment efforts. However, this is often dependent on observational data that are prone to well-known limitations, particularly residual confounding and reverse causality. Several statistical methods have been developed to support stronger causal inference. However, a complementary approach is to use design-based methods for causal inference, which acknowledge sources of bias and attempt to mitigate these through the design of the study rather than solely through statistical adjustment. Genetically informed methods provide a novel and potentially powerful extension to this approach, accounting by design for unobserved genetic and environmental confounding. No single approach will be absent from bias. Instead, we should seek and combine evidence from multiple methodologies that each bring different (and ideally uncorrelated) sources of bias. If the results of these different methodologies align-or triangulate-then we can be more confident in our causal inference. To be truly effective, this should ideally be done prospectively, with the sources of evidence specified in advance, to protect against one final source of bias-our own cognitions, expectations, and fondly held beliefs.

Quantum computing at the frontiers of biological sciences

Computing plays a critical role in the biological sciences but faces increasing challenges of scale and complexity. Quantum computing, a computational paradigm exploiting the unique properties of quantum mechanical analogs of classical bits, seeks to address many of these challenges. We discuss the potential for quantum computing to aid in the merging of insights across different areas of biological sciences.

Application of DNA barcodes and spatial analysis in conservation genetics and modeling of Iranian Salicornia genetic resources

Iran is one of the origins of some Salicornia species. Nevertheless, comprehensive research has not been conducted on genetic potential, distribution, selection of populations, and the economic utilization of Salicornia in Iran. In the current study, Salicornia was collected based on the previous data available for 26 different geographical locations of provinces in Iran. We examined Salicornia plants’ universality DNA barcodes, including rbcL, matK, trnH-psbA, and ITS, and their species identification abilities and identified six species groups. Subsequently, accurate modeling of distributed areas was provided with MAXENT and highlighted the valuable information on the diversity of specific geographical regions, conservation status of existing species, prioritization of conservation areas, and selection of Agro-Ecological areas. Together, this type of integrative study will provide useful information for managing and utilizing Salicornia genetic resources in Iran.

Fast-acting chemical tools to delineate causality in transcriptional control

Multi-dimensional omics profiling continues to illuminate the complexity of cellular processes. Because of difficult mechanistic interpretation of phenotypes induced by slow perturbation, fast experimental setups are increasingly used to dissect causal interactions directly in cells. Here we review a growing body of studies that leverage rapid pharmacological perturbation to delineate causality in gene control. When coupled with kinetically matched readouts, fast chemical genetic tools allow recording of primary phenotypes before confounding secondary effects manifest. The toolbox encompasses directly acting probes, such as active-site inhibitors and proteolysis-targeting chimeras, as well as strategies using genetic engineering to render target proteins chemically tractable, such as analog-sensitive and degron systems. We anticipate that extrapolation of these concepts to single-cell setups will further transform our mechanistic understanding of transcriptional control in the future. Importantly, the concept of leveraging speed to derive causality should be broadly applicable to many aspects of biological regulation.

Genetic influence on the curves of occlusion in children seeking orthodontic treatment

OBJECTIVE

To examine the proportion of variability in the Curve of Wilson (COW) and the Curve of Spee (COS) that is explained by genetic factors in siblings seeking orthodontic treatment.

MATERIALS AND METHODS

Pre-treatment cone-beam computed tomography (CBCT) of 148 sibling patients were selected. The sample consisted of 79 females and 69 males with a mean age of 12 years 7 months. The COS was measured by creating a tangent line from the distobuccal cusp of the mandibular first molars and the highest incisal tip of the mandibular incisors. Measurements were taken from that tangent line to the deepest point on the premolars and canines. The COW was measured using the molar axis line to the perpendicular to WALA (Will Andrews Lawrence Andrews) points' axis line.

RESULTS

The results indicate that these occlusal curves are generally moderate to highly heritable. Heritability of COW-maxilla was 78.3%, heritability of COW-mandible was 43.2% and heritability of COS was 100% (P-value<0.05).

CONCLUSIONS

Most of the developmental variability in the curves of occlusion comes from genetic differences, with very little contribution from environmental factors. Therefore, siblings tend to show similar occlusal curves.

Integrated genetic and metabolic landscapes predict vulnerabilities of temozolomide resistant glioblastoma cells

Metabolic reprogramming and its molecular underpinnings are critical to unravel the duality of cancer cell function and chemo-resistance. Here, we use a constraints-based integrated approach to delineate the interplay between metabolism and epigenetics, hardwired in the genome, to shape temozolomide (TMZ) resistance. Differential metabolism was identified in response to TMZ at varying concentrations in both the resistant neurospheroidal (NSP) and the susceptible (U87MG) glioblastoma cell-lines. The genetic basis of this metabolic adaptation was characterized by whole exome sequencing that identified mutations in signaling pathway regulators of growth and energy metabolism. Remarkably, our integrated approach identified rewiring in glycolysis, TCA cycle, malate aspartate shunt, and oxidative phosphorylation pathways. The differential killing of TMZ resistant NSP by Rotenone at low concentrations with an IC50 value of 5 nM, three orders of magnitude lower than for U87MG that exhibited an IC50 value of 1.8 mM was thus identified using our integrated systems-based approach.

The Boscombe Valley mystery: A lesson in the perils of dogmatism in science

The central dogma enunciated by Francis Crick and the postulate that sequence defines protein structure and function put forth by Christian Anfinsen (also referred to as the Thermodynamics Hypothesis) are some of the most fundamental tenets of molecular biology that have had very profound influences and implications. They were formulated based on observations (evidence) that was obvious to the preceptors. However, as is well known, exception is the rule in biology and several works in the literature cite examples that appear to challenge these dogmas suggesting that being dogmatic can be perilous. In this perspective, using the Boscombe Valley Mystery from Sir Arthur Conan Doyle's fabled Sherlock Holmes stories as a paradigm, I ponder the necessity to revise the two dogmas in light of new evidence, especially concerning prions and intrinsically disordered proteins, much like the call for revising the Modern Synthesis to enunciate the Extended Evolutionary Synthesis.

Next-generation epidemiology: the role of high-resolution molecular phenotyping in diabetes research

Epidemiologists have for many decades reported on the patterns and distributions of diabetes within and between populations and have helped to elucidate the aetiology of the disease. This has helped raise awareness of the tremendous burden the disease places on individuals and societies; it has also identified key risk factors that have become the focus of diabetes prevention trials and helped shape public health recommendations. Recent developments in affordable high-throughput genetic and molecular phenotyping technologies have driven the emergence of a new type of epidemiology with a more mechanistic focus than ever before. Studies employing these technologies have identified gene variants or causal loci, and linked these to other omics data that help define the molecular processes mediating the effects of genetic variation in the expression of clinical phenotypes. The scale of these epidemiological studies is rapidly growing; a trend that is set to continue as the public and private sectors invest heavily in omics data generation. Many are banking on this massive volume of diverse molecular data for breakthroughs in drug discovery and predicting sensitivity to risk factors, response to therapies and susceptibility to diabetes complications, as well as the development of disease-monitoring tools and surrogate outcomes. To realise these possibilities, it is essential that omics technologies are applied to well-designed epidemiological studies and that the emerging data are carefully analysed and interpreted. One might view this as next-generation epidemiology, where complex high-dimensionality data analysis approaches will need to be blended with many of the core principles of epidemiological research. In this article, we review the literature on omics in diabetes epidemiology and discuss how this field is evolving. Graphical abstract.

Massively parallel techniques for cataloguing the regulome of the human brain

Complex brain disorders are highly heritable and arise from a complex polygenic risk architecture. Many disease-associated loci are found in non-coding regions that house regulatory elements. These elements influence the transcription of target genes-many of which demonstrate cell-type-specific expression patterns-and thereby affect phenotypically relevant molecular pathways. Thus, cell-type-specificity must be considered when prioritizing candidate risk loci, variants and target genes. This Review discusses the use of high-throughput assays in human induced pluripotent stem cell-based neurodevelopmental models to probe genetic risk in a cell-type- and patient-specific manner. The application of massively parallel reporter assays in human induced pluripotent stem cells can characterize the human regulome and test the transcriptional responses of putative regulatory elements. Parallel CRISPR-based screens can further functionally dissect this genetic regulatory architecture. The integration of these emerging technologies could decode genetic risk into medically actionable information, thereby improving genetic diagnosis and identifying novel points of therapeutic intervention.

Association of Genetic and Phenotypic Assessments With Onset of Disordered Eating Behaviors and Comorbid Mental Health Problems Among Adolescents

IMPORTANCE

Eating disorders are serious mental disorders with increasing prevalence. Without early identification and treatment, eating disorders may run a long-term course.

OBJECTIVE

To characterize any associations among disordered eating behaviors (DEBs) and other mental health disorders and to identify early associations with the development of symptoms over time.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter, population-based, longitudinal cohort study used data from baseline (collected in 2010), follow-up 1 (collected in 2012), and follow-up 2 (collected in 2015) of the IMAGEN Study, which included adolescents recruited from 8 European sites. The present study assessed data from 1623 healthy adolescents, aged 14 years at baseline, recruited from high schools. Data analyses were performed from January 2018 to September 2019.

MAIN OUTCOMES AND MEASURES

Body mass index (BMI), mental health symptoms, substance use behaviors, and personality variables were investigated as time-varying associations of DEBs (dieting, binge eating, and purging) or change in BMI over time. Polygenic risk scores were calculated to investigate genetic contributions associated with BMI, attention-deficit/hyperactivity disorder (ADHD) and neuroticism to DEBs.

RESULTS

In this cohort study of 1623 adolescents (829 girls [51.1%]) recruited at a mean (SD) age of 14.5 (0.4) years and followed up at ages 16 and 19 years, 278 adolescents (17.1%) reported binge eating, 334 adolescents (20.6%) reported purging, and 356 adolescents (21.9%) reported dieting at 14, 16, or 19 years. Among the precursors of DEBs, high BMI was associated with future dieting (OR, 3.44; 95% CI, 2.09-5.65). High levels of neuroticism (OR, 1.04; 95% CI, 1.01-1.06), conduct problems (OR, 1.41; 95% CI, 1.17-1.69), and deliberate self-harm (OR, 2.18; 95% CI, 1.37-3.45) were associated with future binge eating. Low agreeableness (OR, 0.95; 95% CI, 0.92-0.97), deliberate self-harm (OR, 2.59; 95% CI, 1.69-3.95), conduct problems (OR, 1.42; 95% CI, 1.20-1.68), alcohol misuse (OR, 1.31; 95% CI, 1.10-1.54), and drug abuse (OR, 2.91; 95% CI, 1.78-4.74) were associated with future purging. Polygenetic risk scores for BMI were associated with dieting (at 14 years: OR, 1.27; lower bound 95% CI, 1.08; at 16 years: OR, 1.38; lower bound 95% CI, 1.17); ADHD, with purging (at 16 years: OR, 1.25; lower bound 95% CI, 1.08; at 19 years, OR, 1.23; lower bound 95% CI, 1.06); and neuroticism, with binge eating (at 14 years: OR, 1.32; lower bound 95% CI, 1.11; at 16 years: OR, 1.24; lower bound 95% CI, 1.06), highlighting distinct etiologic overlaps between these traits. The DEBs predated other mental health problems, with dieting at 14 years associated with future symptoms of depression (OR, 2.53; 95% CI, 1.56-4.10), generalized anxiety (OR, 2.27; 95% CI, 1.14-4.51), deliberate self-harm (OR, 2.10; 95% CI, 1.51-4.24), emotional problems (OR, 1.24; 95% CI, 1.08-1.43), and smoking (OR, 2.16; 95% CI, 1.36-3.48). Purging at 14 years was also associated with future depression (OR, 2.87; 95% CI, 1.69-5.01) and anxiety (OR, 2.48; 95% CI, 1.49-4.12) symptoms.

CONCLUSIONS AND RELEVANCE

The findings of this study delineate temporal associations and shared etiologies among DEBs and other mental health disorders and emphasize the potential of genetic and phenotypical assessments of obesity, behavioral disorders, and neuroticism to improve early and differential diagnosis of eating disorders.

The IMAGEN study: a decade of imaging genetics in adolescents

Imaging genetics offers the possibility of detecting associations between genotype and brain structure as well as function, with effect sizes potentially exceeding correlations between genotype and behavior. However, study results are often limited due to small sample sizes and methodological differences, thus reducing the reliability of findings. The IMAGEN cohort with 2000 young adolescents assessed from the age of 14 onwards tries to eliminate some of these limitations by offering a longitudinal approach and sufficient sample size for analyzing gene-environment interactions on brain structure and function. Here, we give a systematic review of IMAGEN publications since the start of the consortium. We then focus on the specific phenotype 'drug use' to illustrate the potential of the IMAGEN approach. We describe findings with respect to frontocortical, limbic and striatal brain volume, functional activation elicited by reward anticipation, behavioral inhibition, and affective faces, and their respective associations with drug intake. In addition to describing its strengths, we also discuss limitations of the IMAGEN study. Because of the longitudinal design and related attrition, analyses are underpowered for (epi-) genome-wide approaches due to the limited sample size. Estimating the generalizability of results requires replications in independent samples. However, such densely phenotyped longitudinal studies are still rare and alternative internal cross-validation methods (e.g., leave-one out, split-half) are also warranted. In conclusion, the IMAGEN cohort is a unique, very well characterized longitudinal sample, which helped to elucidate neurobiological mechanisms involved in complex behavior and offers the possibility to further disentangle genotype × phenotype interactions.

Trans-ethnic and Ancestry-Specific Blood-Cell Genetics in 746,667 Individuals from 5 Global Populations

Most loci identified by GWASs have been found in populations of European ancestry (EUR). In trans-ethnic meta-analyses for 15 hematological traits in 746,667 participants, including 184,535 non-EUR individuals, we identified 5,552 trait-variant associations at p < 5 × 10-9, including 71 novel associations not found in EUR populations. We also identified 28 additional novel variants in ancestry-specific, non-EUR meta-analyses, including an IL7 missense variant in South Asians associated with lymphocyte count in vivo and IL-7 secretion levels in vitro. Fine-mapping prioritized variants annotated as functional and generated 95% credible sets that were 30% smaller when using the trans-ethnic as opposed to the EUR-only results. We explored the clinical significance and predictive value of trans-ethnic variants in multiple populations and compared genetic architecture and the effect of natural selection on these blood phenotypes between populations. Altogether, our results for hematological traits highlight the value of a more global representation of populations in genetic studies.

Explanatory goals and explanatory means in multilevel selection theory

It has become customary in multilevel selection theory to use the same terms (namely "multilevel selection 1" and "multilevel selection 2") to denote both two explanatory goals (explaining why certain individual- and, respectively, group-level traits spread) and two explanatory means (namely, two kinds of group selection we may appeal to in such explanations). This paper spells out some of the benefits that derive from avoiding this terminological conflation. I argue that keeping explanatory means and goals well apart allows us to see that, contrary to a popular recent idea, Price's equation and contextual analysis-the statistical methods most extensively used for measuring the effects of certain evolutionary factors (like individual selection, group selection etc.) on the change in the focal individual trait in multilevel selection scenarios-do not come with built-in notions of group selection and, therefore, the efficacy of these methods at analyzing various kinds of cases does not constitute a basis for deciding how group selection should best be defined. Moreover, contrary to another widely accepted idea, I argue that more than one type of group selection may serve as explanatory means when one's goal is that of explaining the evolution of individual traits in multilevel selection scenarios and I spell out how this explanatory role should be understood.

Genetics of extreme human longevity to guide drug discovery for healthy ageing

Ageing is the greatest risk factor for most common chronic human diseases, and it therefore is a logical target for developing interventions to prevent, mitigate or reverse multiple age-related morbidities. Over the past two decades, genetic and pharmacologic interventions targeting conserved pathways of growth and metabolism have consistently led to substantial extension of the lifespan and healthspan in model organisms as diverse as nematodes, flies and mice. Recent genetic analysis of long-lived individuals is revealing common and rare variants enriched in these same conserved pathways that significantly correlate with longevity. In this Perspective, we summarize recent insights into the genetics of extreme human longevity and propose the use of this rare phenotype to identify genetic variants as molecular targets for gaining insight into the physiology of healthy ageing and the development of new therapies to extend the human healthspan.