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Around the world, adolescents increasingly grow up as members of local and global cultures. Little is known, however, about how precisely adolescents in rapidly globalizing societies blend local and global cultures. Interviews with 40 (16- to 19-year old) Thai adolescents, evenly divided between rural and urban communities, were analyzed alongside participant observation data for the interplay between local and global linguistic and dietary practices. Results revealed that urban adolescents inhabited differentiated selves, alternating between local and global practices based on interactional partner. The activation of each assisted them in navigating—and in some cases, reshaping—hierarchies encountered in everyday relationships. Findings contribute to the developmental science of globalization and point to the utility of interrogating cultural practices as sites of self-negotiation in rapidly changing cultural contexts.

Global change is altering ecosystems at an unprecedented rate. The resulting shifts in species ranges and reproductive timing are opening the potential for hybridization between closely related species which could dramatically alter the genetic diversity, adaptive capacity and evolutionary trajectory of interbreeding taxa. Here, we used behavioural breeding experiments, in vitro fertilization experiments, and whole-transcriptome gene expression data to assess the potential for and consequences of hybridization between Chinook and Coho salmon. We show that behavioural and gametic prezygotic barriers between socio-economically valuable Chinook and Coho salmon are incomplete. Postzygotically, we demonstrate a clear transcriptomic response to hybridization among F₁ Chinook-Coho offspring. Genes transgressively expressed within hybrids were significantly enriched with genes encoded in the nucleus but localized to the mitochondrion, suggesting a potential role for mito-nuclear incompatibilities as a postzygotic mechanism of hybrid breakdown. Chinook and Coho salmon are expected to continue to respond to climate change with shifts in migration timing and habitat use, potentiating hybridization between these species. The downstream consequences of hybridization on the future of these threatened salmon, and the ecosystems they inhabit, is unknown.

Life history strategies, physiological traits, and behavior are thought to covary along a “pace of life” axis, with organisms at the fast end of this continuum having higher fecundity, shorter lifespan, and more rapid development, growth, and metabolic rates. Countergradient variation represents a special case of pace of life variation, in which high-latitude organisms occupy the fast end of the continuum relative to low-latitude conspecifics when compared at a common temperature. Here, we use Atlantic killifish (Fundulus heteroclitus) to explore the role of mitochondrial properties as a mechanism underlying countergradient variation, and thus variation in the pace of life. This species is found along the Atlantic coast of North America, through a steep latitudinal thermal gradient. The northern subspecies has faster development, more rapid growth, higher routine metabolic rate, and higher activity than the southern subspecies when compared at a common temperature. The northern subspecies also has greater mitochondrial respiratory capacity in the liver, although these differences are not evident in other tissues. The increased respiratory capacity of liver mitochondria in northern fish is associated with increases in the activity of multiple electron transport complexes, which largely reflects an increase in the amount of inner mitochondrial membrane per mitochondrion in the northern fish. There are also differences in the lipid composition of liver mitochondrial membranes, including differences in cardiolipin species, which could also influence respiratory capacity. These data suggest that variation in mitochondrial properties could, at least in part, underlie variation in the pace of life in Atlantic killifish.

The broad traits of boldness and independence in domestic horses can affect their usefulness and, indirectly, their welfare. The objective of the current study was to explore associations between attributes that reflect equine boldness and independence with both the age of horses and the age at which they were started under saddle, as well as other variables including breed, colour and primary equestrian discipline. All data were sourced from responses (n = 1940) to the 97-question online Equine Behaviour Assessment and Research Questionnaire (E-BARQ). Twenty E-BARQ items from the dataset were selected to reflect boldness and independence and were tested for univariate significance at p < 0.2. Multivariable modelling of the effect of age on remaining traits was assessed by an ordinal logistic regression, using a cumulative log odds model. This revealed that older horses were bolder (p = 0.012). However, horses started under saddle at an older age were less bold and less independent (p = 0.040 and p = 0.010, respectively). Australian Stock Horses were bolder and more independent (p = 0.014 and p = 0.007, respectively) than crossbreed horses. Horses used for breeding conformation (p = 0.039), working equitation (p = 0.045), eventing (p = 0.044) and traditional working horses (p = 0.034) were bolder than those used for other disciplines. Dressage (p = 0.039) and therapy (p = 0.040) horses were less bold than horses used for other disciplines. Stallions were bolder (p = −0.034) than geldings. Brown (p = 0.049) and chestnut (p = 0.027) horses were less bold than bay horses. Compared to crossbreed horses, Thoroughbreds (p = 0.000) and companion horses (p = 0.017) were less bold whilst heavy horses (p = 0.029) and ponies (p = 0.044) were bolder. Compared to pleasure horses, mounted games horses (p = 0.033) were less independent whereas working equitation horses (p = 0.020) were more independent. Riders with more than eight years’ experience reported more independence in their horses (p = 0.015) than those who had ridden their whole lives. The study findings suggest that boldness and independence are separate traits and only boldness was associated with the age of the horse. Factors that relate to desirable boldness and independence are important in ridden horses because they can affect rider safety. Results from this study should improve horse–rider matching and thereby potentially enhance horse welfare.

The mitonuclear species concept hypothesizes that incompatibilities between interacting gene products of the nuclear and mitochondrial genomes are a major factor establishing and maintaining species boundaries. However, most of the data available to test this concept come from studies of genetic variation in mitochondrial DNA, and clines in the mitochondrial genome across contact zones can be produced by a variety of forces. Here, we show that using a combination of population genomic analyses of the nuclear and mitochondrial genomes and studies of mitochondrial function can provide insight into the relative roles of neutral processes, adaptive evolution, and mitonuclear incompatibility in establishing and maintaining mitochondrial clines, using Atlantic killifish (Fundulus heteroclitus) as a case study. There is strong evidence for a role of secondary contact following the last glaciation in shaping a steep mitochondrial cline across a contact zone between northern and southern subspecies of killifish, but there is also evidence for a role of adaptive evolution in driving differentiation between the subspecies in a variety of traits from the level of the whole organism to the level of mitochondrial function. In addition, studies are beginning to address the potential for mitonuclear incompatibilities in admixed populations. However, population genomic studies have failed to detect evidence for a strong and pervasive influence of mitonuclear incompatibilities, and we suggest that polygenic selection may be responsible for the complex patterns observed. This case study demonstrates that multiple forces can act together in shaping mitochondrial clines, and illustrates the challenge of disentangling their relative roles.

Between 2013 and 2019, 63 presumed Chinook salmon Oncorhynchus tshawytscha sampled primarily in the Strait of Georgia (0.63% of total sample) were identified as potential Chinook–Coho (Oncorhynchus kisutch) hybrids by the presence of anomalous microsatellite genotypes. Their hybrid origin was confirmed by single nucleotide polymorphism amplification of two species‐specific amplicons. Mitochondrial DNA indicated that most of these fish resulted from the hybridization of Coho salmon females and Chinook salmon males. Although no diagnostic external features were identified, several individuals displayed an abnormal scale arrangement on the caudal peduncle. One hybrid juvenile examined for meristics exhibited a pyloric caeca count intermediate between published values for Chinook and Coho salmon. Most hybrids originated in the Cowichan River during the 2014 brood year. Their prevalence in the watershed is a naturally occurring event, likely exacerbated by prolonged low water levels which limit habitat and delay Chinook salmon spawning, in addition to the differential abundance of the parental species. This research is the first to document ongoing natural hybridization (Chinook–Coho salmon crosses) and link it to habitat and climatic changes, and includes the identification of eight F1 adults and two juvenile backcross or F2 hybrids. The potential negative impacts of hybridization, particularly in Coho salmon through potential introgression, warrant hybrid identification as an ecosystem monitoring tool within a survey program. From 2013 to 2019, 63 presumed Chinook salmon sampled primarily in the Strait of Georgia were identified as potential Chinook–Coho hybrids. Their origin was confirmed by nuclear and mitochondrial DNA techniques. Changes in the hydrological regime and spawning time suggest that the observed hybridization is a process resulting from freshwater habitat modification and climatic pressures.

Abstract Phenotypic plasticity is thought to be critical in allowing organisms to cope with environmental change, but the factors that limit this plasticity are poorly understood, which hampers predictions of species resilience to anthropogenic climate change. Here, we ask if limited plasticity in key traits constrains performance at high temperatures, using two California hatchery strains of rainbow trout (Oncorhynchus mykiss). Aerobic and anaerobic metabolic performance declined at a high but ecologically relevant acclimation temperature (24°C), suggesting performance cannot be maintained at this temperature, despite acclimation. Similarly, while both whole-organism thermal tolerance and hypoxia tolerance improved with acclimation to moderately elevated temperatures, compensation was limited at the highest acclimation temperature. These limits at the whole-organism level were aligned with limits at lower levels of biological organization. At the organ level, absolute scope to increase heart rate with acute warming (ΔƒHmax) did not increase between the upper two acclimation temperatures, and the safety margin for cardiac performance decreased at the highest acclimation temperature. At the cellular level, at 24°C, there were transcriptomic changes in the heart consistent with a cellular stress response. These limits across multiple levels of biological organization were observed under conditions that are ecologically relevant at the southern end of the species range, which suggests that thermal plasticity is likely insufficient to buffer rainbow trout against even modest anthropogenic warming in these regions. Lay Summary Understanding the boundaries of acclimation capacity in response to increased temperature can provide valuable insights into conservation and management. In rainbow trout, we show that acclimation limits occur at ecologically relevant temperatures and are aligned with thermal limits across molecular, physiological and whole-animal phenotypes.

The mechanism regulating expression of late genes, encoding viral structural components, is an unresolved problem in the biology of DNA tumor viruses. Here we show that BGLF4, the only protein kinase encoded by Epstein-Barr virus (EBV), controls expression of late genes independent of its effect on viral DNA replication. Ectopic expression of BGLF4 in cells lacking the kinase gene stimulated the transcript levels of six late genes by 8- to 10-fold. Introduction of a BGLF4 mutant that eliminated its kinase activity did not stimulate late gene expression. In cells infected with wild-type EBV, siRNA to BGLF4 (siG4) markedly reduced late gene expression without compromising viral DNA replication. Synthesis of late products was restored upon expression of a form of BGLF4 resistant to the siRNA. Studying the EBV transcriptome using mRNA-seq during the late phase of the lytic cycle in the absence and presence of siG4 showed that BGLF4 controlled expression of 31 late genes. Analysis of the EBV transcriptome identified BGLF3 as a gene whose expression was reduced as a result of silencing BGLF4. Knockdown of BGLF3 markedly reduced late gene expression but had no effect on viral DNA replication or expression of BGLF4. Our findings reveal the presence of a late control locus encompassing BGLF3 and BGLF4 in the EBV genome, and provide evidence for the importance of both proteins in post-replication events that are necessary for expression of late genes.

An evidence-based understanding of dangerous or unwelcome behaviour in horses would greatly benefit both horses and humans who interact with them. Using owner-reported data from the Equine Behaviour Assessment and Research Questionnaire (E-BARQ), the current study investigated in-hand behaviours associated with dangerous or unwelcome ridden behaviours, notably bolting, rearing and bucking. Respondents (n = 1584) to the ridden horse section of the E-BARQ answered 42 demographic questions, followed by 268 behavioural items. Parallel analysis was conducted to group individual behaviours into rotated components to create independent and dependent indices. Multivariable general linear modelling and ordinal logistic regression were used to identify behaviours associated with bolting, rearing and bucking. Results revealed that safety-from-bolt increased as social confidence with horses (Odds ratio (OR) = 1.06; 95% confidence interval (cf = 1.02–1.09) and other animals (OR = 1.08; cf = 1.03–1.12), compliance in-hand (OR = 1.10; cf = 1.06–1.16) and tolerance of restraint (OR = 1.05; cf = 1.0–1.11) increased; and decreased as loading problems (OR = 0.95; cf = 0.92–0.99) increased. Safety-from-rear increased as tolerance of restraint (OR = 1.07; cf = 1.02–1.12) and social confidence with other animals (OR = 1.05; cf = 1.01–1.09) increased; and decreased as loading problems (OR = 0.94; cf = 0.91–0.98) increased. Safety-from-buck increased as social confidence with horses (b-value = 0.011, p < 0.001) and other animals (b-value = 0.010, p = 0.002), compliance in-hand (b-value = 0.015, p < 0.001), tolerance of restraint (b-value = 0.009, p = 0.027) and tolerance of haltering/bridling (b-value = 0.016, p = 0.010) increased, and it decreased as loading problems increased (b-value = −0.011, p < 0.001). By revealing, for the first time, that specific behaviours on the ground are associated with particular responses in the same horses when ridden, this study advances equitation science considerably. Identification of risk factors for dangerous behaviour while under saddle can improve safety for horses and riders and highlights the importance of effective and humane in-hand training.

The Strait of Messina separates Italy from Sicily by only a few kilometres of famously turbulent sea. During the Roman period, the Strait was at times described as a bridge and gateway to opportunity, a symbol of empire and little more than a river easily forded. At others, it was an insurmountable divide, the most dangerous of all passages, and a hard boundary between Romans and non-Romans. In both contexts, the Strait continued to operate as an agent of connectivity, the crossroads of varied cultural groups from across the ancient Mediterranean, situated as it was between the Tyrrhenian and Ionian seas. My research conducted at the BSR in 2020 and again in 2022 explored the tripartite nature of the Strait of Messina as bridge, division and crossroads in the Roman period, as part of my PhD project The Strait of Messina in the Roman World: Connectivity, Space, and Identity between Italy and Sicily (300 BCE – 400 CE).