Diet and the evolution of human amylase gene copy number variation

A universally applicable definition for domestication

The process of domestication is commonly perceived as a human achievement, and domestic species are typically assumed to be those under human control. Domestic species have emerged from a greater diversity of interactions than this perspective allows, and none of the many definitions proposed for domestication can readily, reliably, and consistently distinguish domestic and nondomestic populations. Here, we propose that the process of domestication should instead be defined solely as evolution of a nonhuman population in response to an anthropogenic niche and that a domestic population is one that cannot sustain itself outside of an anthropogenic niche. As a result, this definition does not require comparisons with a presumed and largely unobservable ancestor. Instead, it focuses on the observable relationship between a nonhuman population and humans. It also avoids making assumptions about how domestication happens, thus enabling an exploration of the mechanisms underlying the process of adaptation to an anthropogenic niche. By applying this definition to plants, animals, and microbes, we illustrate its utility for investigating the evolution of the relationship between humans and other species and for anticipating which species are likely to survive in an increasingly human-influenced world. Domestication is simply an evolutionary process resulting from the interaction between two species, one of which is human. As we work to protect Earth's biodiversity, this definition allows us to understand why, in response to the conditions human societies create, some species survive and thrive, while others struggle and go extinct.

Examining the impact of 28-week multicomponent and strength exercises on brain health, salivary stress, and mental well-being in frail older women: A controlled trial analysis

BACKGROUND

In recent years, the efficacy of various physical exercise programs in enhancing functional fitness among frail older adults has gained recognition. However, limited research has concurrently explored the long-term effects of exercise on brain health, stress biomarkers, and mental well-being. This study aimed to investigate the impact of two distinct chair-based exercise programs on salivary stress hormones and psychological well-being in frail older women over a 28-week period.

METHODS

A total of 140 individuals participated in the enrollment phase, with 84 eligible participants randomly assigned to three groups. Following the intervention, data from 60 participants were analyzed across the multicomponent exercise (MCE, n = 23), elastic band muscle-strength exercise (ESE, n=19), and non-exercise control (CG n=18) groups. Salivary biomarkers of alpha-amylase (α-AMY) Cortisol (COR), alpha-amylase/cortisol ratio, psychological indicators and physical frailty (PF) and functional fitness were assessed pre- and post-intervention.

RESULTS

Salivary COR levels exhibited a significant time × group interaction, with a moderate increase in MCE, a small decrease in ESE, and a substantial increase in CGne. Salivary α-AMY levels varied significantly over time and by group, with a small decrease in both exercise groups and a moderate increase in CGne. The α-AMY /COR ratio also displayed a significant interaction effect. Additionally, significant improvements were observed in PF compound scores, general self-efficacy, attitudes toward aging, and reductions in perceived stress and depressive symptoms (p < 0.05).

CONCLUSIONS

Notably, the MCE program demonstrated greater benefits than ESE. The observed associations between changes in α-AMY levels, mental well-being, and functional fitness indicators contribute novel evidence on the psychophysiological adaptations to long-term exercise. Importantly, reductions in PF scores correlated with improvements in self-efficacy, attitudes toward aging, and handgrip strength, reinforcing the link between functional fitness, stress regulation, and psychological well-being. These findings emphasize the need for tailored exercise interventions to enhance both physiological resilience and mental health in frail older populations.

Gene-Diet Interactions in Diabetes Mellitus: Current Insights and the Potential of Personalized Nutrition

Type 2 diabetes mellitus (T2DM) remaina significant global health challenge, with its increasing prevalence and associated complications contributing to high morbidity and economic burden. Genetic factors play a crucial role in T2DM susceptibility, yet individual responses to dietary interventions vary widely, emphasizing the importance of gene-diet (G × D) interactions. This review synthesizes the current literature on the genetic basis of T2DM and the role of G × D interactions in shaping individual responses to diet. We examine the genetics implication in T2DM risk and modulation by dietary factors, with a focus on the potential of Nutrigenetics in guiding personalized nutrition (PN) strategies. Moreover, the clinical implications of these interactions for the personalized prevention and management of T2DM are explored, highlighting the promise of tailoring dietary recommendations based on genetic profiles. Critical research gaps, including the need for diverse and longitudinal studies, the integration of multi-omic data, and the inclusion of digital health technologies in PN are discussed. Finally, future directions for the field are outlined, advocating for more inclusive, large-scale studies to optimize PN approaches for diverse populations and improve the efficacy of T2DM prevention and management. This review underscores the potential of an individualized, genetically informed dietary approach in modulating the global burden of T2DM.

Personalized Nutrition Strategies for Patients in the Intensive Care Unit: A Narrative Review on the Future of Critical Care Nutrition

Introduction: Critically ill patients in intensive care units (ICUs) are at high risk of malnutrition, which can result in muscle atrophy, polyneuropathy, increased mortality, or prolonged hospitalizations with complications and higher costs during the recovery period. They often develop ICU-acquired weakness, exacerbated by sepsis, immobilization, and drug treatments, leading to rapid muscle mass loss and long-term complications. Studies indicate that adequate protein and calorie intake can decrease mortality and improve prognosis and recovery. However, optimal implementation remains a critical challenge. Objectives: This narrative review aims to summarize recent advances in nutritional strategies for critically ill patients. It highlights the benefits and limitations of current approaches including enteral (EN) and parenteral nutrition (PN) and examines their impact on clinical outcomes and overall mortality. Additionally, the review explores the emerging role of precision nutrition in critical care using technologies such as metabolomics and artificial intelligence (AI) to provide valuable insights into optimizing nutritional care in critically ill patients. Methods: A comprehensive literature search was conducted to identify recent studies, clinical guidelines, and expert consensus papers on nutritional support for ICU patients. The investigation focused on critical aspects such as the optimal timing for intervention, the route of administration, specific protein and energy targets, and technological innovations to support personalized nutrition, ensuring that each patient receives tailored support based on their unique needs. Results: Guidelines recommend initiating EN or PN nutrition within the first 48 h of admission, using indirect calorimetry (IC) to estimate energy needs, and supplementing protein up to 1.2 g/kg/day after stabilization. IC has gained importance in assessing energy needs but is still underused in the ICU. EN is preferred because it maintains intestinal integrity, reduces the risk of infections, and is recommended within the first 48 h of ICU admission. PN is used when EN is infeasible, but it increases the risk of infection. By integrating metabolomics with transcriptomic and genomic data, we can gain a deeper understanding of the effect of nutrition on cellular homeostasis, facilitating personalized treatments and enhancing the recovery of critically ill patients. Conclusions: AI is becoming increasingly important in monitoring and evaluating artificial nutrition, providing a more accurate and efficient alternative to traditional methods. AI can assist in identifying and managing malnutrition and is effective for estimating caloric and nutrient intake. AI minimizes human error, enables continuous monitoring, and integrates various data sources. The nutritional care of critically ill patients requires collaboration among specialists from diverse fields, including physicians, nutritionists, pharmacists, radiologists, IT experts, and policymakers.

Obesity Parameters in Women Is Associated With AMY1 Gene Copy Number, Nesfatin-1 Level, and Dietary Intake: A Case-Control Study

AMY1 gene copy number (GCN) variations and the satiety hormone Nesfatin-1 have recently emerged as potential contributors to obesity and related metabolic disturbances. This study evaluated the relationship between AMY1 GCN, Nesfatin-1 level, and nutritional status in obese/overweight and normal-weight women. Participants included 40 normal-weight and 45 overweight/obese women aged 19-50. Data were collected through a demographic and dietary habits questionnaire, a 3-day food recall, anthropometric measurements, and body composition analysis via bioelectrical impedance. Saliva samples were used to measure AMY1 GCN and Nesfatin-1 levels. The AMY1 GCN was significantly lower in overweight/obese participants compared to normal-weight participants. Increased AMY1 GCN was associated with a decrease in BMI (-0.154 units), while increased Nesfatin-1 level was linked to a rise in BMI (0.196 units) (p < 0.05). Women with low AMY1 GCN had higher daily intakes of energy, carbohydrate, protein, and fat (p < 0.05). This study highlights the significant roles of AMY1 GCN and Nesfatin-1 in the development of obesity. The findings suggest that lower AMY1 GCN and higher Nesfatin-1 levels are associated with unfavorable nutritional and metabolic profiles. Further comprehensive studies on genetic and hormonal factors, including AMY1 GCN and Nesfatin-1, are recommended to guide obesity prevention and treatment strategies.

Seeking consensus on the domestication concept

The domestication of plants and animals permitted the development of cities and social hierarchies, as well as fostering cultural changes that ultimately led humanity into the modern world. Despite the importance of this set of related evolutionary phenomena, scholars have not reached a consensus on what the earliest steps in the domestication process looked like, how long the seminal portions of the process took to unfold, or whether humans played a conscious role in parts or all of it. Likewise, many scholars find it difficult to disentangle the cultural processes of cultivation from the biological processes of domestication. Over the past decade, the prevailing views among scholars have begun to shift towards unconscious and protracted models of early domestication; however, the nomenclature used to discuss these changes has been stagnant. Discussions of early domestication remain bound up in prevailing definitions and preconceived ideas of what the process looked like. In this paper, we seek to break down definitions of domestication and to construct a definition that serves equal utility regardless of the views that researchers hold about the process.This article is part of the theme issue 'Unravelling domestication: multi-disciplinary perspectives on human and non-human relationships in the past, present and future'.

Evaluation of Genomic Proximity Mapping (GPM) for Detecting Genomic and Chromosomal Structural Variants in Constitutional Disorders

Genomic structural variants (SVs) are critical contributors to genetic diversity and disease, yet their detection remains challenging with conventional cytogenetic techniques, such as karyotyping, fluorescence in situ hybridization (FISH), and chromosome microarray analysis (CMA). These methods often lack the resolution and sensitivity needed for comprehensive characterization of chromosomal aberrations. To address these limitations, we implemented genomic proximity mapping (GPM), a genome-wide chromosome conformation capture technology, in a clinical setting. In this study, we applied GPM to a cohort of 123 patients with constitutional disorders, achieving a 100% concordance rate in detecting 411 CNVs and 39 structural rearrangements, in addition to novel findings missed by standard methods. GPM demonstrated unique advantages, such as resolving both balanced and unbalanced chromosomal rearrangements with precise (<5kb) breakpoint resolution, maintaining robust performance with challenging samples, including formalin-fixed, paraffin-embedded (FFPE) tissues, and detecting mosaicism with high sensitivity. Furthermore, GPM reliably provided detailed copy number and loss-of-heterozygosity profiles, streamlining workflows and enhancing diagnostic resolution. GPM represents a transformative tool for genomic diagnostics, offering a high-resolution, comprehensive approach to detecting diverse genomic alterations. Its ability to address limitations of conventional cytogenetics methods positions GPM as a needed advance in the diagnosis, prognosis, and therapeutic management of genetic disorders.

Evolutionary medicine and bioastronautics: an innovative approach in addressing adverse mental health effects to astronauts during long term space missions

Although evolutionary medicine has produced several novel insights for explaining prevalent health issues, it has yet to sufficiently address possible adverse mental health effects of humans during long-term space missions While evolutionary applications to medicine have increased over the past 20 years, there is scope for the integration of evolutionary applications in the new branch of space medicine called bioastronautics, which analyses the effects on human bodies when in outer space. Evolutionary principles may explain what kinds of space environments increase mental health risks to astronauts, both in the short and long term; secondly, evolutionary principles may provide a more informed understanding of the evolutionary mismatch between terrestrial and space environments in which astronauts exist. This information may assist in developing frameworks for improving mental health of astronauts and future space colonists. Consequently, this paper will focus on some of the major evolutionary mismatches currently confronting astronauts' mental health, with an aim to improve medical knowledge. It will also provide possible therapeutic countermeasures based on evolutionary principles for reducing adverse mental effects on astronauts.

Systems genetics uncovers associations among host amylase locus, gut microbiome, and metabolic traits in mice

BACKGROUND

Population studies have revealed associations between host genetic and gut microbiome in humans and mice. However, the molecular bases for how host genetic variation impacts the gut microbial community and bacterial metabolic niches remain largely unknown.

RESULTS

We leveraged 90 inbred hyperlipidemic mouse strains from the hybrid mouse diversity panel (HMDP), previously studied for a variety of cardio-metabolic traits. Metagenomic analysis of cecal DNA followed by genome-wide association analysis identified genomic loci that were associated with microbial enterotypes in the gut. Among these, we detected a genetic locus surrounding multiple amylase genes that were associated with abundances of Firmicutes (Lachnospiraceae family) and Bacteroidetes (Muribaculaceae family) taxa encoding distinct starch and sugar degrading capabilities. The genetic variants at the amylase gene locus were associated with distinct gut microbial communities (enterotypes) with different predicted metabolic capacities for carbohydrate degradation. Mendelian randomization analysis revealed host phenotypes, including liver fibrosis and plasma HDL-cholesterol levels, that were associated with gut microbiome enterotypes.

CONCLUSIONS

This work reveals novel relationships among host genetic variation, gut microbial enterotypes, and host metabolic traits and supports the notion that variation of host amylase may represent a key determinant of gut microbiome in mice. Video Abstract.

Population genomics advances in frontier ethnic minorities in China

China, with its large geographic span, possesses rich genetic diversity across vast frontier regions in addition to the Han Chinese majority. Importantly, demographic events and various natural and cultural environments in Chinese frontier regions have shaped the genomic diversity of ethnic minorities via local adaptations. Thus, insights into the genetic diversity and adaptive evolution of these under-represented ethnic groups are crucial for understanding evolutionary scenarios and biomedical implications in East Asian populations. Here, we focus on ethnic minorities in Chinese frontier regions and review research advances regarding genomic diversity, genetic structure, population history, genetic admixture, and local adaptation. We first provide an overview of the extensive genetic diversity across populations in different Chinese frontier regions. Next, we summarize research progress regarding genetic ancestry, demographic history, the adaptive process, and the archaic identification of multiple ethnic minorities in different Chinese frontier regions. Finally, we discuss the gaps and opportunities in genomic studies of Chinese populations and the need for a more comprehensive understanding of genomic diversity and the evolution of populations of East Asian ancestry in the post-genomic era.

Human and bacterial genetic variation shape oral microbiomes and health

It is largely unknown which human genetic variants shape a person's oral microbiome and potentially promote its dysbiosis. We characterized the oral microbiomes of 12,519 people by analyzing whole-genome sequencing reads from previously sequenced saliva-derived DNA. Human genetic variation at 11 loci (10 novel) associated with differences in oral microbiome composition. Nearly all of these associations implicated candidate genes with readily interpretable functions, several related to carbohydrate availability. The strongest association ( p =3.0x10 -188 ) involved the common FUT2 W154X loss-of-function variant, which associated with the abundances of 32 bacterial species. Human host genetics also appeared to powerfully shape within-species genetic variation in oral bacteria. Variation at the 11 human loci associated with variation in gene dosages in 68 regions of bacterial genomes. Several such associations implicated interactions of bacterial proteins with histo-blood group antigens presented on host mucosal cell surfaces and salivary proteins. Common, multi-allelic copy-number variation of AMY1 , which encodes salivary amylase, associated with oral microbiome composition ( p =1.5x10 -53 ) and with dentures use in UK Biobank ( p =5.9x10 -35 , n=418k), suggesting that amylase abundance impacts oral health by influencing the oral microbiome. Two other microbiome composition-associated loci, FUT2 and PITX1 , also significantly associated with dentures risk, collectively nominating numerous microbial taxa that might contribute to tooth decay.

Decoding metabolic connections: the role of salivary amylase activity in modulating visceral fat and triglyceride glucose index

BACKGROUND

Salivary amylase activity (SAA) is recognized as a potential biomarker for metabolic health. Previous studies suggest an association between SAA and insulin sensitivity, but the mechanisms remain unclear. This study investigates the relationship between SAA, visceral fat (VF), and the triglyceride-glucose (TyG) index to clarify the pathways linking SAA to metabolic risk factors.

METHODS

This cross-sectional study analysed data from women of reproductive age who were classified as overweight. Linear regression models were used to assess associations between salivary amylase activity (SAA), visceral fat (VF) and the triglyceride-glucose (TyG) index, while adjusting for confounding variables such as age, body mass index (BMI), physical activity and dietary patterns. Mediation analysis was conducted to determine whether VF mediates the relationship between SAA and the TyG index.

RESULTS

Higher SAA was inversely associated with VF (β = -0.45, 95% CI: -0.65 to -0.25, p < 0.001). No direct association was observed between SAA and TyG index (β = -0.10, 95% CI: -0.25 to 0.05, p = 0.18) after adjustment for covariates. Mediation analysis revealed that visceral fat significantly mediated the relationship between SAA and the TyG index. The indirect effect of SAA on the TyG index through VF (A × B) was statistically significant (β = -0.16, 95% CI: -0.26 to -0.08), accounting for 45% of the total effect.

CONCLUSIONS

These findings suggest that higher SAA may confer metabolic benefits by reducing VF, thereby indirectly influencing the TyG index. This highlights the critical role of VF in mediating the protective effects of SAA on metabolic health and provides insights into potential pathways for intervention.

Genome-wide profiling of highly similar paralogous genes using HiFi sequencing

Variant calling is hindered in segmental duplications by sequence homology. We developed Paraphase, a HiFi-based informatics method that resolves highly similar genes by phasing all haplotypes of paralogous genes together. We applied Paraphase to 160 long (>10 kb) segmental duplication regions across the human genome with high (>99%) sequence similarity, encoding 316 genes. Analysis across five ancestral populations revealed highly variable copy numbers of these regions. We identified 23 paralog groups with exceptionally low within-group diversity, where extensive gene conversion and unequal crossing over contribute to highly similar gene copies. Furthermore, our analysis of 36 trios identified 7 de novo SNVs and 4 de novo gene conversion events, 2 of which are non-allelic. Finally, we summarized extensive genetic diversity in 9 medically relevant genes previously considered challenging to genotype. Paraphase provides a framework for resolving gene paralogs, enabling accurate testing in medically relevant genes and population-wide studies of previously inaccessible genes.

Inferring the Selective History of CNVs Using a Maximum Likelihood Model

Copy number variations (CNVs)-structural variations generated by deletion and/or duplication that result in a change in DNA dosage-are prevalent in nature. CNVs can drastically affect the phenotype of an organism and have been shown to be both involved in genetic disorders and be used as raw material in adaptive evolution. Unlike single-nucleotide variations, the often large and varied effects of CNVs on phenotype hinders our ability to infer their selective advantage based on the population genetics data. Here, we present a likelihood-based approach, dubbed PoMoCNV (POlymorphism-aware phylogenetic MOdel for CNVs), that estimates the evolutionary parameters such as mutation rates among different copy numbers and relative fitness loss per copy deletion at a genomic locus based on population genetics data. As a case study, we analyze the genomics data of 40 strains of Caenorhabditis elegans, representing four different populations. We take advantage of the data on chromatin accessibility to interpret the mutation rate and fitness of copy numbers, as inferred by PoMoCNV, specifically in open or closed chromatin loci. We further test the reliability of PoMoCNV by estimating the evolutionary parameters of CNVs for mutation-accumulation experiments in C. elegans with varying levels of genetic drift.

Biases in machine-learning models of human single-cell data

Recent machine-learning (ML)-based advances in single-cell data science have enabled the stratification of human tissue donors at single-cell resolution, promising to provide valuable diagnostic and prognostic insights. However, such insights are susceptible to biases. Here we discuss various biases that emerge along the pipeline of ML-based single-cell analysis, ranging from societal biases affecting whose samples are collected, to clinical and cohort biases that influence the generalizability of single-cell datasets, biases stemming from single-cell sequencing, ML biases specific to (weakly supervised or unsupervised) ML models trained on human single-cell samples and biases during the interpretation of results from ML models. We end by providing methods for single-cell data scientists to assess and mitigate biases, and call for efforts to address the root causes of biases.

Genome-wide association testing beyond SNPs

Decades of genetic association testing in human cohorts have provided important insights into the genetic architecture and biological underpinnings of complex traits and diseases. However, for certain traits, genome-wide association studies (GWAS) for common SNPs are approaching signal saturation, which underscores the need to explore other types of genetic variation to understand the genetic basis of traits and diseases. Copy number variation (CNV) is an important source of heritability that is well known to functionally affect human traits. Recent technological and computational advances enable the large-scale, genome-wide evaluation of CNVs, with implications for downstream applications such as polygenic risk scoring and drug target identification. Here, we review the current state of CNV-GWAS, discuss current limitations in resource infrastructure that need to be overcome to enable the wider uptake of CNV-GWAS results, highlight emerging opportunities and suggest guidelines and standards for future GWAS for genetic variation beyond SNPs at scale.

The Impact of Human Salivary Amylase Gene Copy Number and Starch on Oral Biofilms

The copy number (CN) variant AMY1 encodes the salivary amylase enzyme which promotes starch digestion. Although this gene has been associated with dental caries and periodontal disease susceptibility, the impact of the interaction between AMY1 CN and starch on oral biofilms is unclear. We explored how oral microbiota communities shaped by AMY1 CN respond to starch by employing an in vitro model of biofilm formation. We cultured biofilms using saliva samples from 31 donors with a range of AMY1 CNs (between 2 and 20 copies) and self-reported gum disease states; we used media with and without starch. Many of the most prevalent genera in saliva were also prevalent in the derived biofilms. The presence of starch in the media was associated with lower biofilm alpha diversity. We found a significant interaction between AMY1 CN and the media carbohydrate content that influenced the proportions of Atopobium and Veillonella. Members of these genera have been associated with dental caries and periodontitis. These findings suggest that the effects of carbohydrates on oral microbiome composition depend on AMY1 CN and that human oral bacteria evolved in response to expansion of this host gene locus.

Convergent Evolution and Predictability of Gene Copy Numbers Associated with Diets in Mammals

Convergent evolution, the evolution of the same or similar phenotypes in phylogenetically independent lineages, is a widespread phenomenon in nature. If the genetic basis for convergent evolution is predictable to some extent, it may be possible to infer organismic phenotypes and the capability of organisms to utilize new ecological resources based on genome sequence data. While repeated amino acid changes have been studied in association with convergent evolution, relatively little is known about the potential contribution of repeated gene copy number changes. In this study, we explore whether gene copy number changes of particular gene families are linked to diet shifts in mammals and assess whether trophic ecology can be inferred from the copy numbers of a specific set of gene families. Using 86 mammalian genome sequences, we identified 24 gene families with a trend toward higher copy numbers in herbivores, carnivores, and omnivores, even after phylogenetic corrections. We were able to confirm previous findings on genes such as amylase, olfactory receptors, and xenobiotic metabolism genes, and identify novel gene families whose copy numbers correlate with dietary patterns. For example, omnivores exhibited higher copy numbers of genes encoding regulators of translation. We also established a discriminant function based on the copy numbers of 13 gene families that can help predict trophic ecology to some extent. These findings highlight a possible association between convergent evolution and repeated copy number changes in specific gene families, suggesting the potential to develop a method for predicting animal ecology from genome sequence data.

Investigating the hydrolysis of complex carbohydrates with salivary α-amylase

Currently, little is known about how complex carbohydrates (maltodextrins) with varying degrees of polymerisation (DP) and molecular branching interact with α-amylase in human saliva and the associated amounts and structures of generated reducing sugars. Therefore, this study aimed to investigate salivary α-amylase and the subsequent reducing sugars generated with complex carbohydrate stimuli. A secondary aim was to investigate reducing sugar generation and complex carbohydrate taste sensitivity. Whole, stimulated saliva was collected from 32 participants. Two maltodextrin samples were used (short chain maltodextrin (SCM), average DP 6, and long chain maltodextrin (LCM), average DP 20) with and without the α-amylase inhibitor, acarbose. The concentration of reducing sugars generated by the salivary α-amylase was determined and high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) was used to investigate their molecular chain profiles. Complex carbohydrate taste sensitivity was measured using detection threshold (DT) and suprathreshold intensity perception methods (ST). The addition of acarbose significantly reduced the amount of reducing sugars generated for both LCM and SCM samples (p = 0.0001). The LCM sample produced a significantly higher amount of reducing sugars than the SCM sample (p = 0.0001). For the LCM sample, there was no effect of complex carbohydrate taste sensitivity on reducing sugar generation (all p > 0.05). For the SCM sample, evidence suggests that reducing sugar generation may be impact complex carbohydrate sensitivity (DT: p = 0.059, ST: p = 0.076). In conclusion, DP of the maltodextrins impacted the amount of reducing sugars generated. Furthermore, there was evidence to suggest that an interaction exists between complex carbohydrate taste sensitivity and the generation of reducing sugars.

Structural polymorphism and diversity of human segmental duplications

Segmental duplications (SDs) contribute significantly to human disease, evolution and diversity but have been difficult to resolve at the sequence level. We present a population genetics survey of SDs by analyzing 170 human genome assemblies (from 85 samples representing 38 Africans and 47 non-Africans) in which the majority of autosomal SDs are fully resolved using long-read sequence assembly. Excluding the acrocentric short arms and sex chromosomes, we identify 173.2 Mb of duplicated sequence (47.4 Mb not present in the telomere-to-telomere reference) distinguishing fixed from structurally polymorphic events. We find that intrachromosomal SDs are among the most variable, with rare events mapping near their progenitor sequences. African genomes harbor significantly more intrachromosomal SDs and are more likely to have recently duplicated gene families with higher copy numbers than non-African samples. Comparison to a resource of 563 million full-length isoform sequencing reads identifies 201 novel, potentially protein-coding genes corresponding to these copy number polymorphic SDs.

Moringa oleifera in a modern time: A comprehensive review of its nutritional and bioactive composition as a natural solution for managing diabetes mellitus by reducing oxidative stress and inflammation

Globally, diabetes mellitus (DM) and its complications are considered among the most significant public health problems. According to numerous scientific studies, Plants and their bioactive compounds may reduce inflammation and oxidative stress (OS), leading to a reduction in the progression of DM. Moringa oleifera (MO), widely used in Ayurvedic and Unani medicine for centuries because of its health-promoting characteristics, particularly its ability to control DM and its related complications. MO is a multi-purpose plant that has an impressive range of nutritional components including proteins, amino acids (Essential and non-essential amino acids), carbs, fats, fiber, vitamins, and phenolic compounds. In the modern era, scientists have paid close attention to the anti-diabetic, anti-oxidative and anti-inflammatory attributes and other medicinal properties, of MO leaves and seeds. MO leaves and seeds have modulatory effects on DM that are likely influenced by multiple mechanisms. Some of these mechanisms include direct effects, but other mechanisms involve inhibition the production of inflammatory markers, modulation of the gut microbiome, reduction of OS, enhancement of glucose metabolism through hexokinase and glucose 6-phosphate dehydrogenase, improve insulin sensitivity and glucose uptake in the liver and muscles. Overall, these findings suggest that MO may play a role in lowering the risk of DM and its related outcomes. The purpose of this review is to provide a comprehensive overview of the nutritional and bioactive profiles of MO leaves and seeds, as well as to investigate their possible anti-diabetic effects by modulating oxidative stress and inflammation. Our results indicate that MO may be a beneficial natural resource for management of DM and related issues by lowering oxidative stress and inflammation. Furthermore, studies on MO has yielded promising findings in diabetic animal models, indicating antioxidant and anti-inflammatory properties. However, human trials have shown less solid results, most likely due to a lack of studies, different techniques, and dosages. More clinical research is needed to fully understand MO's anti-diabetic potential, notably in lowering oxidative stress and inflammation, both of which are critical in controlling diabetes complications.

[Thousands of years of human-dog relationship]

During recent years, much progress has been made in understanding the origin and evolution of the dog. Thanks to the collaboration between zooarchaeology, genomics and paleogenetics, researchers were able to hypothesize scenarios regarding the origins of the canine lineages present in Europe at the end of the Pleistocene and the beginning of the Holocene. Research has also shown a correlation between human and canine migration across time and space, highlighting a strong relationship between man and his best friend. This proximity between the two species is also illustrated by the adaptation of this species to anthropogenic selective pressures, particularly in parallel with cultural transitions. Although the history of this species still requires much exploration to be fully understood, these results provide new theoretical bases for understanding the interplay between humans and dogs.

Diversity and consequences of structural variation in the human genome

The biomedical community is increasingly invested in capturing all genetic variants across human genomes, interpreting their functional consequences and translating these findings to the clinic. A crucial component of this endeavour is the discovery and characterization of structural variants (SVs), which are ubiquitous in the human population, heterogeneous in their mutational processes, key substrates for evolution and adaptation, and profound drivers of human disease. The recent emergence of new technologies and the remarkable scale of sequence-based population studies have begun to crystalize our understanding of SVs as a mutational class and their widespread influence across phenotypes. In this Review, we summarize recent discoveries and new insights into SVs in the human genome in terms of their mutational patterns, population genetics, functional consequences, and impact on human traits and disease. We conclude by outlining three frontiers to be explored by the field over the next decade.

Streptococcus abundance and oral site tropism in humans and non-human primates reflects host and lifestyle differences

The genus Streptococcus is highly diverse and a core member of the primate oral microbiome. Streptococcus species are grouped into at least eight phylogenetically-supported clades, five of which are found almost exclusively in the oral cavity. We explored the dominant Streptococcus phylogenetic clades in samples from multiple oral sites and from ancient and modern-day humans and non-human primates and found that clade dominance is conserved across human oral sites, with most Streptococcus reads assigned to species falling in the Sanguinis or Mitis clades. However, minor differences in the presence and abundance of individual species within each clade differentiated human lifestyles, with loss of S. sinensis appearing to correlate with toothbrushing. Of the non-human primates, only baboons show clade abundance patterns similar to humans, suggesting that a habitat and diet similar to that of early humans may favor the growth of Sanguinis and Mitis clade species.

Double or nothing: Ancient duplications in the amylase locus drove human adaptation

Salivary and pancreatic amylase are encoded by AMY1 and AMY2, respectively, which are located within a single genomic locus that has undergone substantial structural variation, resulting in varying gene copy numbers across species. Using optical genome mapping and long-read sequencing, Yilmaz, Karageorgiou, Kim, et al. achieved nucleotide-level resolution of this locus across different human populations, offering new insights into how copy number variation contributes to human adaptation.

Cell-autonomous adaptation: an overlooked avenue of adaptation in human evolution

Adaptation to environmental conditions occurs over diverse evolutionary timescales. In multi-cellular organisms, adaptive traits are often studied in tissues/organs relevant to the environmental challenge. We argue for the importance of an underappreciated layer of evolutionary adaptation manifesting at the cellular level. Cell-autonomous adaptations (CAAs) are inherited traits that boost organismal fitness by enhancing individual cell function. For instance, the cell-autonomous enhancement of mitochondrial oxygen utilization in hypoxic environments differs from an optimized erythropoiesis response, which involves multiple tissues. We explore the breadth of CAAs across challenges and highlight their counterparts in unicellular organisms. Applying these insights, we mine selection signals in Andean highlanders, revealing novel candidate CAAs. The conservation of CAAs across species may reveal valuable insights into multi-cellular evolution.

Parallel Signatures of Diet Adaptation in the Invasive Common Myna Genome

Invasive species offer uniquely replicated model systems to study rapid adaptation. The common myna (Acridotheres tristis) has been introduced to over a dozen countries and is classified as one of the most invasive birds in the world. Their multiple invasions provide an opportunity to identify repeated adaptation, as invasive populations originated from multiple source populations. We compared whole-genome resequencing data from 80 individuals from four native and seven invasive populations, representing two independent introduction pathways. Results from two different selection scan methods were combined and identified a strongly selected region on chromosome 8 that spans two copies of AMY2A, part of the alpha-amylase gene family, a putative ncRNA and an insertion-deletion structural variant (SV) that contains an ERVK transposable element (TE). Outlier SNPs and the SV are polymorphic in native populations, but fixed or close-to-fixed in the two invasive pathways, with the fixation of the same alleles in two independent lineages providing evidence for parallel selection on standing variation. Intriguingly, the second copy of AMY2A has a non-conservative missense mutation at a phylogenetically conserved site. This mutation, alongside variation in the SV, TE and ncRNA, provide possible routes for changes to protein function or expression. AMY2A has been associated with human commensalism in house sparrows, and genes in this family have been linked to adaptation to high-starch diets in humans and dogs. This study illustrates the value of replicated analyses within and across species to understand rapid adaptation at the molecular level.

Genes, culture, and scientific racism

Quantitative studies of cultural evolution and gene-culture coevolution (henceforth "CE" and "GCC") emerged in the 1970s, in the aftermath of the "race and intelligence quotient (IQ)" and "human sociobiology" debates, as a counter to extreme hereditarian positions. These studies incorporated cultural transmission and its interaction with genetics in contributing to patterns of human variation. Neither CE nor GCC results were consistent with racist claims of ubiquitous genetic differences between socially defined races. We summarize how genetic data refute the notion of racial substructure for human populations and address naive interpretations of race across the biological sciences, including those related to ancestry, health, and intelligence, that help to perpetuate racist ideas. A GCC perspective can refute reductionist and determinist claims while providing a more inclusive multidisciplinary framework in which to interpret human variation.

Reconstruction of the human amylase locus reveals ancient duplications seeding modern-day variation

Previous studies suggested that the copy number of the human salivary amylase gene, AMY1, correlates with starch-rich diets. However, evolutionary analyses are hampered by the absence of accurate, sequence-resolved haplotype variation maps. We identified 30 structurally distinct haplotypes at nucleotide resolution among 98 present-day humans, revealing that the coding sequences of AMY1 copies are evolving under negative selection. Genomic analyses of these haplotypes in archaic hominins and ancient human genomes suggest that a common three-copy haplotype, dating as far back as 800,000 years ago, has seeded rapidly evolving rearrangements through recurrent nonallelic homologous recombination. Additionally, haplotypes with more than three AMY1 copies have significantly increased in frequency among European farmers over the past 4000 years, potentially as an adaptive response to increased starch digestion.

Independent expansion, selection, and hypervariability of the TBC1D3 gene family in humans

TBC1D3 is a primate-specific gene family that has expanded in the human lineage and has been implicated in neuronal progenitor proliferation and expansion of the frontal cortex. The gene family and its expression have been challenging to investigate because it is embedded in high-identity and highly variable segmental duplications. We sequenced and assembled the gene family using long-read sequencing data from 34 humans and 11 nonhuman primate species. Our analysis shows that this particular gene family has independently duplicated in at least five primate lineages, and the duplicated loci are enriched at sites of large-scale chromosomal rearrangements on Chromosome 17. We find that all human copy-number variation maps to two distinct clusters located at Chromosome 17q12 and that humans are highly structurally variable at this locus, differing by as many as 20 copies and ∼1 Mbp in length depending on haplotypes. We also show evidence of positive selection, as well as a significant change in the predicted human TBC1D3 protein sequence. Last, we find that, despite multiple duplications, human TBC1D3 expression is limited to a subset of copies and, most notably, from a single paralog group: TBC1D3-CDKL These observations may help explain why a gene potentially important in cortical development can be so variable in the human population.

A Catalogue of Structural Variation across Ancestrally Diverse Asian Genomes

Structural variants (SVs) are significant contributors to inter-individual genetic variation associated with traits and diseases. Current SV studies using whole-genome sequencing (WGS) have a largely Eurocentric composition, with little known about SV diversity in other ancestries, particularly from Asia. Here, we present a WGS catalogue of 73,035 SVs from 8392 Singaporeans of East Asian, Southeast Asian and South Asian ancestries, of which ~65% (47,770 SVs) are novel. We show that Asian populations can be stratified by their global SV patterns and identified 42,239 novel SVs that are specific to Asian populations. 52% of these novel SVs are restricted to one of the three major ancestry groups studied (Indian, Chinese or Malay). We uncovered SVs affecting major clinically actionable loci. Lastly, by identifying SVs in linkage disequilibrium with single-nucleotide variants, we demonstrate the utility of our SV catalogue in the fine-mapping of Asian GWAS variants and identification of potential causative variants. These results augment our knowledge of structural variation across human populations, thereby reducing current ancestry biases in global references of genetic variation afflicting equity, diversity and inclusion in genetic research.

Nepali oral microbiomes reflect a gradient of lifestyles from traditional to industrialized

BACKGROUND

Lifestyle plays an important role in shaping the gut microbiome. However, its contributions to the oral microbiome remain less clear, due to the confounding effects of geography and methodology in investigations of populations studied to date. Furthermore, while the oral microbiome seems to differ between foraging and industrialized populations, we lack insight into whether transitions to and away from agrarian lifestyles shape the oral microbiota. Given the growing interest in so-called "vanishing microbiomes" potentially being a risk factor for increased disease prevalence in industrialized populations, it is important that we distinguish lifestyle from geography in the study of microbiomes across populations.

RESULTS

Here, we investigate salivary microbiomes of 63 Nepali individuals representing a spectrum of lifestyles: foraging, subsistence farming (individuals that transitioned from foraging to farming within the last 50 years), agriculturalists (individuals that have transitioned to farming for at least 300 years), and industrialists (expatriates that immigrated to the USA within the last 20 years). We characterize the role of lifestyle in microbial diversity, identify microbes that differ between lifestyles, and pinpoint specific lifestyle factors that may be contributing to differences in the microbiomes across populations. Contrary to prevailing views, when geography is controlled for, oral microbiome alpha diversity does not differ significantly across lifestyles. Microbiome composition, however, follows the gradient of lifestyles from foraging through agrarianism to industrialism, supporting the notion that lifestyle indeed plays a role in the oral microbiome. Relative abundances of several individual taxa, including Streptobacillus and an unclassified Porphyromonadaceae genus, also mirror lifestyle. Finally, we identify specific lifestyle factors associated with microbiome composition across the gradient of lifestyles, including smoking and grain sources.

CONCLUSION

Our findings demonstrate that by studying populations within Nepal, we can isolate an important role of lifestyle in determining oral microbiome composition. In doing so, we highlight the potential contributions of several lifestyle factors, underlining the importance of carefully examining the oral microbiome across lifestyles to improve our understanding of global microbiomes. Video Abstract.

Sea cucumbers and their symbiotic microbiome have evolved to feed on seabed sediments

Sea cucumbers are predominant deposit feeders in benthic ecosystems, providing protective benefits to coral reefs by reducing disease prevalence. However, how they receive sufficient nutrition from seabed sediments remains poorly understood. Here, we investigate Holothuria leucospilota, an ecologically significant tropical sea cucumber, to elucidate digestive mechanisms underlying marine deposit-feeding. Genomic analysis reveals intriguing evolutionary adaptation characterized by an expansion of digestive carbohydrase genes and a contraction of digestive protease genes, suggesting specialization in digesting microalgae. Developmentally, two pivotal dietary shifts, namely, from endogenous nutrition to planktonic feeding, and from planktonic feeding to deposit feeding, induce changes in digestive tract enzyme profiles, with adults mainly expressing carbohydrases and lipases. A nuanced symbiotic relationship exists between gut microbiota and the host, namely, specific resident bacteria supply crucial enzymes for food digestion, while other bacteria are digested and provide assimilable nutrients. Our study further identifies Holothuroidea lineage-specific lysozymes that are restrictedly expressed in the intestines to support bacterial digestion. Overall, this work advances our knowledge of the evolutionary innovations in the sea cucumber digestive system which enable them to efficiently utilize nutrients from seabed sediments and promote food recycling within marine ecosystems.

Gelada genomes highlight events of gene flow, hybridisation and local adaptation that track past climatic changes

Theropithecus gelada, the last surviving species of this genus, occupy a unique and highly specialised ecological niche in the Ethiopian highlands. A subdivision into three geographically defined populations (Northern, Central and Southern) has been tentatively proposed for this species on the basis of genetic analyses, but genomic data have been investigated only for two of these groups (Northern and Central). Here we combined newly generated whole genome sequences of individuals sampled from the population living south of the East Africa Great Rift Valley with available data from the other two gelada populations to reconstruct the evolutionary history of the species. Integrating genomic and paleoclimatic data we found that gene-flow across populations and with Papio species tracked past climate changes. The isolation and climatic conditions experienced by Southern geladas during the Holocene shaped local diversity and generated diet-related genomic signatures.

Deciphering the role of structural variation in human evolution: a functional perspective

Advances in sequencing technologies have enabled the comparison of high-quality genomes of diverse primate species, revealing vast amounts of divergence due to structural variation. Given their large size, structural variants (SVs) can simultaneously alter the function and regulation of multiple genes. Studies estimate that collectively more than 3.5% of the genome is divergent in humans versus other great apes, impacting thousands of genes. Functional genomics and gene-editing tools in various model systems recently emerged as an exciting frontier - investigating the wide-ranging impacts of SVs on molecular, cellular, and systems-level phenotypes. This review examines existing research and identifies future directions to broaden our understanding of the functional roles of SVs on phenotypic innovations and diversity impacting uniquely human features, ranging from cognition to metabolic adaptations.

Influence of AMY1 gene copy number on salivary amylase activity changes induced by exercise in young adults

Human salivary amylase secretion increases in response to stress; the activity has been reported to rise significantly with high-intensity exercise. The human salivary amylase gene (AMY1) has copy number variation, with the copy number correlating with salivary amylase activity. However, the relationship between individual AMY1 copy number and salivary amylase activity in response to exercise remains unclear. In this study, we investigated AMY1 copy number and fluctuations in amylase activity in 42 healthy university students (25 males and 17 females). Participants engaged in intermittent round-trip interval training on a basketball court. Saliva samples were collected pre- and post-exercise to measure amylase activity. DNA was extracted from the oral mucosa, and AMY1 copy number was quantified using RT-PCR. Results showed a significant increase in amylase activity postexercise. Additionally, amylase activity pre- and post-exercise was positively correlated with AMY1 copy number. The generalize linear model showed that the exercise-induced increase in amylase activity per AMY1 gene was negatively related to the AMY1 copy number and aerobic fitness. Gender has no effect on amylase activity. These results suggest a different mechanism for the constitutive and exercise-induced amylase secretion, while aerobic fitness may be independently involved in the secretion.

Differential expression of cardiometabolic and inflammation markers and signaling pathways between overweight/obese Qatari adults with high and low plasma salivary α-amylase activity

BACKGROUND

The relationship between salivary α-amylase activity (sAAa) and susceptibility to cardiovascular disorders lacks a definitive consensus in available studies. To fill this knowledge gap, the present study endeavors to investigate this association among overweight/obese otherwise healthy Qatari adults. The study specifically categorizes participants based on their sAAa into high and low subgroups, aiming to provide a more comprehensive understanding of the potential link between sAAa levels and cardiovascular and inflammation markers in this population.

METHODS

Plasma samples of 264 Qatari overweight/obese (Ow/Ob) participants were used to quantify the sAAa and to profile the proteins germane to cardiovascular, cardiometabolic, metabolism, and organ damage in low sAAa (LsAAa) and high sAAa (HsAAa) subjects using the Olink technology. Comprehensive statistical tools as well as chemometric and enrichments analyses were used to identify differentially expressed proteins (DEPs) and their associated signaling pathways and cellular functions.

RESULTS

A total of ten DEPs were detected, among them five were upregulated (QPCT, LCN2, PON2, DPP7, CRKL) while five were down regulated in the LsAAa subgroup compared to the HsAAa subgroup (ARG1, CTSH, SERPINB6, OSMR, ALDH3A). Functional enrichment analysis highlighted several relevant signaling pathways and cellular functions enriched in the DEPs, including myocardial dysfunction, disorder of blood pressure, myocardial infraction, apoptosis of cardiomyocytes, hypertension, chronic inflammatory disorder, immunes-mediated inflammatory disease, inflammatory response, activation of leukocytes and activation of phagocytes.

CONCLUSION

Our study unveils substantial alterations within numerous canonical pathways and cellular or molecular functions that bear relevance to cardiometabolic disorders among Ow/Ob Qatari adults exhibiting LsAAa and HsAAa in the plasma. A more comprehensive exploration of these proteins and their associated pathways and functions offers the prospect of elucidating the mechanistic underpinnings inherent in the documented relationship between sAAa and metabolic disorders.

Recurrent evolution and selection shape structural diversity at the amylase locus

The adoption of agriculture triggered a rapid shift towards starch-rich diets in human populations1. Amylase genes facilitate starch digestion, and increased amylase copy number has been observed in some modern human populations with high-starch intake2, although evidence of recent selection is lacking3,4. Here, using 94 long-read haplotype-resolved assemblies and short-read data from approximately 5,600 contemporary and ancient humans, we resolve the diversity and evolutionary history of structural variation at the amylase locus. We find that amylase genes have higher copy numbers in agricultural populations than in fishing, hunting and pastoral populations. We identify 28 distinct amylase structural architectures and demonstrate that nearly identical structures have arisen recurrently on different haplotype backgrounds throughout recent human history. AMY1 and AMY2A genes each underwent multiple duplication/deletion events with mutation rates up to more than 10,000-fold the single-nucleotide polymorphism mutation rate, whereas AMY2B gene duplications share a single origin. Using a pangenome-based approach, we infer structural haplotypes across thousands of humans identifying extensively duplicated haplotypes at higher frequency in modern agricultural populations. Leveraging 533 ancient human genomes, we find that duplication-containing haplotypes (with more gene copies than the ancestral haplotype) have rapidly increased in frequency over the past 12,000 years in West Eurasians, suggestive of positive selection. Together, our study highlights the potential effects of the agricultural revolution on human genomes and the importance of structural variation in human adaptation.

Gene expansions contributing to human brain evolution

Genomic drivers of human-specific neurological traits remain largely undiscovered. Duplicated genes expanded uniquely in the human lineage likely contributed to brain evolution, including the increased complexity of synaptic connections between neurons and the dramatic expansion of the neocortex. Discovering duplicate genes is challenging because the similarity of paralogs makes them prone to sequence-assembly errors. To mitigate this issue, we analyzed a complete telomere-to-telomere human genome sequence (T2T-CHM13) and identified 213 duplicated gene families likely containing human-specific paralogs (>98% identity). Positing that genes important in universal human brain features should exist with at least one copy in all modern humans and exhibit expression in the brain, we narrowed in on 362 paralogs with at least one copy across thousands of ancestrally diverse genomes and present in human brain transcriptomes. Of these, 38 paralogs co-express in gene modules enriched for autism-associated genes and potentially contribute to human language and cognition. We narrowed in on 13 duplicate gene families with human-specific paralogs that are fixed among modern humans and show convincing brain expression patterns. Using long-read DNA sequencing revealed hidden variation across 200 modern humans of diverse ancestries, uncovering signatures of selection not previously identified, including possible balancing selection of CD8B. To understand the roles of duplicated genes in brain development, we generated zebrafish CRISPR "knockout" models of nine orthologs and transiently introduced mRNA-encoding paralogs, effectively "humanizing" the larvae. Morphometric, behavioral, and single-cell RNA-seq screening highlighted, for the first time, a possible role for GPR89B in dosage-mediated brain expansion and FRMPD2B function in altered synaptic signaling, both hallmark features of the human brain. Our holistic approach provides important insights into human brain evolution as well as a resource to the community for studying additional gene expansion drivers of human brain evolution.

Detecting adaptive changes in gene copy number distribution accompanying the human out-of-Africa expansion

Genes with multiple copies are likely to be maintained by stabilizing selection, which puts a bound to unlimited expansion of copy number. We designed a model in which copy number variation is generated by unequal recombination, which fits well with several genes surveyed in three human populations. Based on this theoretical model and computer simulations, we were interested in determining whether the gene copy number distribution in the derived European and Asian populations can be explained by a purely demographic scenario or whether shifts in the distribution are signatures of adaptation. Although the copy number distribution in most of the analyzed gene clusters can be explained by a bottleneck, such as in the out-of-Africa expansion of Homo sapiens 60-10 kyrs ago, we identified several candidate genes, such as AMY1A and PGA3, whose copy numbers are likely to differ among African, Asian, and European populations.

We Are What, When, And How We Eat: The Evolutionary Impact of Dietary Shifts on Physical and Cognitive Development, Health, and Disease

"We are what, when, and how we eat": the evolution of human dietary habits mirrors the evolution of humans themselves. Key developments in human history, such as the advent of stone tool technology, the shift to a meat-based diet, control of fire, advancements in cooking and fermentation techniques, and the domestication of plants and animals, have significantly influenced human anatomical, physiological, social, cognitive, and behavioral changes. Advancements in scientific methods, such as the analysis of microfossils like starch granules, plant-derived phytoliths, and coprolites, have yielded unprecedented insights into past diets. Nonetheless, the isolation of ancient food matrices remains analytically challenging. Future technological breakthroughs and a more comprehensive integration of paleogenomics, paleoproteomics, paleoglycomics, and paleometabolomics will enable a more nuanced understanding of early human ancestors' diets, which holds the potential to guide contemporary dietary recommendations and tackle modern health challenges, with far-reaching implications for human well-being, and ecological impact on the planet.

Butterflies in your stomach? Not an issue for nearly 8000 species of fishes

The gastric stomach is a hallmark of vertebrate evolution, yet is missing in nearly 25% of living fish species and some mammals. New work by Kato et al. shows how a cassette of genes relating to acid production, pepsins, cell adhesion, and developmental control are repeatedly lost in animals that have also lost their stomachs.

Structural variation in humans and our primate kin in the era of telomere-to-telomere genomes and pangenomics

Structural variants (SVs) account for the majority of base pair differences both within and between primate species. However, our understanding of inter- and intra-species SV has been historically hampered by the quality of draft primate genomes and the absence of genome resources for key taxa. Recently, advances in long-read sequencing and genome assembly have begun to radically reshape our understanding of SVs. Two landmark achievements include the publication of a human telomere-to-telomere (T2T) genome as well as the development of the first human pangenome reference. In this review, we first look back to the major works laying the foundation for these projects. We then examine the ways in which T2T genome assemblies and pangenomes are transforming our understanding of and approach to primate SV. Finally, we discuss what the future of primate SV research may look like in the era of T2T genomes and pangenomics.

Dendritic spines and their role in the pathogenesis of neurodevelopmental and neurological disorders

Since Cajal introduced dendritic spines in the 19th century, they have attained considerable attention, especially in neuropsychiatric and neurologic disorders. Multiple roles of dendritic spine malfunction and pathology in the progression of various diseases have been reported. Thus, it is inevitable to consider these structures as new therapeutic targets for treating neuropsychiatric and neurologic disorders such as autism spectrum disorders, schizophrenia, dementia, Down syndrome, etc. Therefore, we attempted to prepare a narrative review of the literature regarding the role of dendritic spines in the pathogenesis of aforementioned diseases and to shed new light on their pathophysiology.

Digesting the complex metabolic effects of diet on the host and microbiome

The past 50 years of interdisciplinary research in humans and model organisms has delivered unprecedented insights into the mechanisms through which diet affects energy balance. However, translating these results to prevent and treat obesity and its associated diseases remains challenging. Given the vast scope of this literature, we focus this Review on recent conceptual advances in molecular nutrition targeting the management of energy balance, including emerging dietary and pharmaceutical interventions and their interactions with the human gut microbiome. Notably, multiple current dietary patterns of interest embrace moderate-to-high fat intake or prioritize the timing of eating over macronutrient intake. Furthermore, the rapid expansion of microbiome research findings has complicated multiple longstanding tenets of nutrition while also providing new opportunities for intervention. Continued progress promises more precise and reliable dietary recommendations that leverage our growing knowledge of the microbiome, the changing landscape of clinical interventions, and our molecular understanding of human biology.

Local genetic adaptation to habitat in wild chimpanzees

How populations adapt to their environment is a fundamental question in biology. Yet we know surprisingly little about this process, especially for endangered species such as non-human great apes. Chimpanzees, our closest living relatives, are particularly interesting because they inhabit diverse habitats, from rainforest to woodland-savannah. Whether genetic adaptation facilitates such habitat diversity remains unknown, despite having wide implications for evolutionary biology and conservation. Using 828 newly generated exomes from wild chimpanzees, we find evidence of fine-scale genetic adaptation to habitat. Notably, adaptation to malaria in forest chimpanzees is mediated by the same genes underlying adaptation to malaria in humans. This work demonstrates the power of non-invasive samples to reveal genetic adaptations in endangered populations and highlights the importance of adaptive genetic diversity for chimpanzees.

Nepali oral microbiomes reflect a gradient of lifestyles from traditional to industrialized

Background

Lifestyle plays an important role in shaping the gut microbiome. However, its contributions to the oral microbiome remains less clear, due to the confounding effects of geography and methodology in investigations of populations studied to date. Furthermore, while the oral microbiome seems to differ between foraging and industrialized populations, we lack insight into whether transitions to and away from agrarian lifestyles shape the oral microbiota. Given the growing interest in so-called 'vanishing microbiomes' potentially being a risk factor for increased disease prevalence in industrialized populations, it is important that we distinguish lifestyle from geography in the study of microbiomes across populations.

Results

Here, we investigate salivary microbiomes of 63 Nepali individuals representing a spectrum of lifestyles: foraging, subsistence farming (individuals that transitioned from foraging to farming within the last 50 years), agriculturalists (individuals that have transitioned to farming for at least 300 years), and industrialists (expatriates that immigrated to the United States within the last 20 years). We characterize the role of lifestyle in microbial diversity, identify microbes that differ between lifestyles, and pinpoint specific lifestyle factors that may be contributing to differences in the microbiomes across populations. Contrary to prevailing views, when geography is controlled for, oral microbiome alpha diversity does not differ significantly across lifestyles. Microbiome composition, however, follows the gradient of lifestyles from foraging through agrarianism to industrialism, supporting the notion that lifestyle indeed plays a role in the oral microbiome. Relative abundances of several individual taxa, including Streptobacillus and an unclassified Porphyromonadaceae genus, also mirror lifestyle. Finally, we identify specific lifestyle factors associated with microbiome composition across the gradient of lifestyles, including smoking and grain source.

Conclusion

Our findings demonstrate that by controlling for geography, we can isolate an important role for lifestyle in determining oral microbiome composition. In doing so, we highlight the potential contributions of several lifestyle factors, underlining the importance of carefully examining the oral microbiome across lifestyles to improve our understanding of global microbiomes.

Detection and enzymatic characterization of human saliva amylase

As a rule, an experiment carried out at school or in undergraduate study courses is rather simple and not very informative. However, when the experiments are to be performed using modern methods, they are often abstract and difficult to understand. Here, we describe a quick and simple experiment, namely the enzymatic characterization of ptyalin (human salivary amylase) using a starch degradation assay. With the experimental setup presented here, enzyme parameters, such as pH optimum, temperature optimum, chloride dependence, and sensitivity to certain chemicals can be easily determined. This experiment can serve as a good model for enzyme characterization in general, as modern methods usually follow the same principle: determination of the activity of the enzyme under different conditions. As different alleles occur in humans, a random selection of test subjects will be quite different with regard to ptyalin activities. Therefore, when the students measure their own ptyalin activity, significant differences will emerge, and this will give them an idea of the genetic diversity in human populations. The evaluation has shown that the pupils have gained a solid understanding of the topic through this experiment.