Environment Interaction Research Research Articles

Development and Validation of an Animal Thermal Environment Interaction Laboratory

HighlightsA custom-designed laboratory for thermal environment interaction research was constructed.All instrumentation systems were commissioned.Operation performance of the laboratory with sows was evaluated.Abstract. A pilot-scale laboratory was designed and built to meet the specific needs of conducting precision livestock farming (PLF) research related to animal response to its thermal environment. The two room (8.5 × 3.7 × 2.9 m; W × L × H) laboratory was built inside an existing structure utilizing common construction methods and materials. Each room was fully instrumented to characterize the thermal (dry-bulb temperature and relative humidity) and gaseous (O2, CO2) environment and facilitate both direct and indirect calorimetry measurements. The laboratory’s instrumentation set-up allows for expansion into additional thermal (black-globe temperature), lighting analysis (wavelength and intensity), and gas (NH3) as experiments demand. Ventilation was a “modified push-pull” style with one common supply fan and an exhaust fan for each room operating at a slight negative pressure. Each room also featured an airflow measurement device that was individually calibrated. The commissioning of the environmental control demonstrated all sensors were functioning correctly. Operational performance of the laboratory with sows demonstrated the ventilation and environmental controls were effective at controlling room temperature when ambient temperature was warmer than room setpoint. This laboratory can be used for various poultry and swine experiments for developing and refining PLF technologies before advancing to field trials in commercial facilities. Unique and extensive research laboratories are needed to readily facilitate the research and development of PLF technologies related to characterizing and controlling the animal occupied zone thermal environment that align with industry needs. Traditional production facilities present challenges related to biosecurity, instrumentation capabilities, labor, and travel to remote sites. Keywords: Commissioning, PLF, Poultry, Swine, Ventilation.

Three phases of Gene × Environment interaction research: Theoretical assumptions underlying gene selection.

Some Gene × Environment interaction (G×E) research has focused upon single candidate genes, whereas other related work has targeted multiple genes (e.g., polygenic scores). Each approach has informed efforts to identify individuals who are either especially vulnerable to the negative effects of contextual adversity (diathesis stress) or especially susceptible to both positive and negative contextual conditions (differential susceptibility). A critical step in all such molecular G×E research is the selection of genetic variants thought to moderate environmental influences, a subject that has not received a great deal of attention in critiques of G×E research (beyond the observation of small effects of individual genes). Here we conceptually distinguish three phases of G×E work based on the selection of genes presumed to moderate environmental effects and the theoretical basis of such decisions: (a) single candidate genes, (b) composited (multiple) candidate genes, and (c) GWAS-derived polygenic scores. This illustrative, not exhaustive, review makes it clear that implicit or explicit theoretical assumptions inform gene selection in ways that have not been clearly articulated or fully appreciated.

Models of Behavior/Environment Interactions: Towards a Better-Informed Design

The field of environmental design is a vastly interdisciplinary field. Behavioral and social sciences have been the source for man/people-environment interaction knowledge that feeds such environmental design fields as: architecture, landscape architecture, urban design, and urban planning. Social or behavioral scientists have been conducting these researches for decades. However, sometimes local designers, design researchers and practitioners face shortage of access to man/people - environment interaction research. Today there is a need to supply local designers and practitioners with procedures and practices for conducting research to inform their design with the necessary knowledge to predict and accommodate user behavior in their designs, thereby guaranteeing a higher quality of life in the built environment in general. The current paper demonstrates and reviews different theoretical perspectives that conceptualize man/people - environments interaction and points out to related environmental design research applications. different models of man/people - environment interaction are explained in terms of the mechanism that links people and environment. A detailed analysis is conducted comparing models in terms of philosophy of science, unit of analysis and phenomena being studied and field of application.

Genetic Moderation of Stress Effects on Corticolimbic Circuitry.

Stress exposure is associated with individual differences in corticolimbic structure and function that often mirror patterns observed in psychopathology. Gene x environment interaction research suggests that genetic variation moderates the impact of stress on risk for psychopathology. On the basis of these findings, imaging genetics, which attempts to link variability in DNA sequence and structure to neural phenotypes, has begun to incorporate measures of the environment. This research paradigm, known as imaging gene x environment interaction (iGxE), is beginning to contribute to our understanding of the neural mechanisms through which genetic variation and stress increase psychopathology risk. Although awaiting replication, evidence suggests that genetic variation within the canonical neuroendocrine stress hormone system, the hypothalamic-pituitary-adrenal axis, contributes to variability in stress-related corticolimbic structure and function, which, in turn, confers risk for psychopathology. For iGxE research to reach its full potential it will have to address many challenges, of which we discuss: (i) small effects, (ii) measuring the environment and neural phenotypes, (iii) the absence of detailed mechanisms, and (iv) incorporating development. By actively addressing these challenges, iGxE research is poised to help identify the neural mechanisms underlying genetic and environmental associations with psychopathology.

Candidate Gene–Environment Interaction Research

Studying how genetic predispositions come together with environmental factors to contribute to complex behavioral outcomes has great potential for advancing the understanding of the development of psychopathology. It represents a clear theoretical advance over studying these factors in isolation. However, research at the intersection of multiple fields creates many challenges. We review several reasons why the rapidly expanding candidate gene–environment interaction (cG×E) literature should be considered with a degree of caution. We discuss lessons learned about candidate gene main effects from the evolving genetics literature and how these inform the study of cG×E. We review the importance of the measurement of the gene and environment of interest in cG×E studies. We discuss statistical concerns with modeling cG×E that are frequently overlooked. Furthermore, we review other challenges that have likely contributed to the cG×E literature being difficult to interpret, including low power and publication bias. Many of these issues are similar to other concerns about research integrity (e.g., high false-positive rates) that have received increasing attention in the social sciences. We provide recommendations for rigorous research practices for cG×E studies that we believe will advance its potential to contribute more robustly to the understanding of complex behavioral phenotypes.

Homogeneity and heterogeneity as situational properties: producing--and moving beyond?--race in post-genomic science.

In this article, we explore current thinking and practices around the logics of difference in gene-environment interaction research in the post-genomic era. We find that scientists conducting gene-environment interaction research continue to invoke well-worn notions of racial difference and diversity, but use them strategically to try to examine other kinds of etiologically significant differences among populations. Scientists do this by seeing populations not as inherently homogeneous or heterogeneous, but rather by actively working to produce homogeneity along some dimensions and heterogeneity along others in their study populations. Thus we argue that homogeneity and heterogeneity are situational properties--properties that scientists seek to achieve in their study populations, the available data, and other aspects of the research situation they are confronting, and then leverage to advance post-genomic science. Pointing to the situatedness of homogeneity and heterogeneity in gene-environment interaction research underscores the work that these properties do and the contingencies that shape decisions about research procedures. Through a focus on the situational production of homogeneity and heterogeneity more broadly, we find that gene-environment interaction research attempts to shift the logic of difference from solely racial terms as explanatory ends unto themselves, to racial and other dimensions of difference that may be important clues to the causes of complex diseases.

Genetics in Population Health Science: Strategies and Opportunities

Translational research is needed to leverage discoveries from the frontiers of genome science to improve public health. So far, public health researchers have largely ignored genetic discoveries, and geneticists have ignored important aspects of population health science. This mutual neglect should end. In this article, we discuss 3 areas where public health researchers can help to advance translation: (1) risk assessment: investigate genetic profiles as components in composite risk assessments; (2) targeted intervention: conduct life-course longitudinal studies to understand when genetic risks manifest in development and whether intervention during sensitive periods can have lasting effects; and (3) improved understanding of environmental causation: collaborate with geneticists on gene-environment interaction research. We illustrate with examples from our own research on obesity and smoking.

Life stress, the dopamine receptor gene, and emerging adult drug use trajectories: a longitudinal, multilevel, mediated moderation analysis.

This study was designed to examine the prospective relations of life stress and genetic status with increases in drug use. African Americans (N = 399) in rural Georgia (Wave 1 mean age = 17 years) provided three waves of data across 27.5 months and a saliva sample from which the dopamine receptor D4 (DRD4) gene was genotyped. Multilevel growth curve modeling analysis indicated that emerging adults manifested the highest escalations in drug use when they reported high life stress and carried an allele of DRD4 with 7 or more repeats (7 + R allele). In addition, emerging adults who reported high life stress and carried the 7 + R allele evinced the largest increases in two proximal risk factors for drug use: affiliations with drug-using companions and drug use vulnerability cognitions. Furthermore, when the Gene × Environment interaction effects on the increases in affiliations with drug-using companions and vulnerability cognitions were entered into the model forecasting drug use, the Life Stress × DRD4 Status interaction on drug use became nonsignificant in the presence of the risk mechanisms. This finding provides an example of "second generation" Gene × Environment interaction research in which the interaction's effects on proximal risk mechanisms account for its effects on outcomes.

The developmental origins of externalizing behavioral problems: Parental disengagement and the role of gene–environment interplay

A line of research has revealed that the influence of genes on behavioral development is closely tied to environmental experiences. Known as gene–environment interaction, research in this area is beginning to reveal that variation in parenting behaviors may moderate genetic influences on antisocial behaviors in children. Despite growing interest in gene–environment interaction research, little evidence exists concerning the role of maternal disengagement in the conditioning of genetic influences on childhood behavioral problems. The current study is intended to address this gap in the literature by analyzing a sample of twin pairs drawn from the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B). Analysis of the ECLS-B provided evidence that maternal disengagement moderates genetic influences on the development of externalizing problems.

Spatial and temporal patterns of wildfire ignitions in Canada from 1980 to 2006

A spatially explicit baseline measure of historic, current and future wildfire ignition expectations is required to monitor and understand changes in fire occurrence, the distribution of which climate change is anticipated to modify. Using spatial–temporal patterns of fire in Canada, we present a method to identify baseline expectations and ignition trends between 1980 and 2006 across 1-km spatial units. Kernel density estimates of wildfire ignitions and temporal trajectory metrics were calculated to describe expected ignition density, variability from expected density, and increasing or decreasing density trends. Baseline ignition expectations and trends were used to create unique fire ignition regimes and assess anthropogenic influence on ignitions. Fire ignition densities decreased exponentially as distance to road or populated place increased, and largest ignition trends occurred closest to both variables. Fire ignition regime delineation was more dependent on human transportation networks than human settlement. These findings provide a unique approach to quantifying ignition expectations. This research highlights the potential of this baseline approach for monitoring efforts and fire–environment interaction research and offers a preliminary spatially explicit model of wildfire occurrence expectations in Canada.

GL.05 Controversies in gene–environment interaction research: why all the fuss?

There has been considerable interest in recent years in the role of gene×environment (G×E) interactions in the aetiology of psychiatric disorders. While the fact that genetic effects may moderate the...

Prenatal programming of postnatal plasticity?

Evidence indicates that maternal prenatal distress predicts problematic health and behavioral outcomes in children as well as infant/child cortisol levels and negative emotionality as reviewed here. Evidence that these physiological and behavioral characteristics themselves moderate environmental effects on development in a "for better and for worse" manner consistent with Belsky's differential susceptibility hypothesis and Boyce and Ellis' notions of biological sensitivity to context raises the prospect that susceptibility to rearing is a function of nurture (i.e., fetal environment), consistent with Boyce and Ellis' proposal that plasticity can be shaped by developmental experience. This hypothesis is supported by new findings from the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development showing that low birth weight, a marker for an adverse prenatal environment, predicts infant difficult temperament, which is a susceptibility factor that we previously showed as moderating, in a for better and for worse manner, the effects of parenting and child care quality on socioemotional functioning. Moreover, recent Gene × Environment interaction research raises the prospect that some fetuses may be more susceptible to such "prenatal programming of postnatal plasticity" as a result of their genetic makeup. If this proves true, it will be consistent with the conclusion that early developmental plasticity is a function of both nature and nurture and may be evolutionarily adaptive, a further possibility considered in the discussion.

Gene-Lifestyle and Gene-Pharmacotherapy Interactions in Obesity and Its Cardiovascular Consequences

Obesity is a highly prevalent complex trait that raises the risk of other chronic diseases such as type 2 diabetes, certain cancers, sleep apnea, and cardiovascular disease, and shortens lifespan. Clinical intervention studies focused on weight loss and epidemiological studies of obesity indicate that genetic variation may modify the relationship between lifestyle behaviors and weight loss or weight gain. Similar observations have also emerged from pharmacogenetic studies. The literature includes several reports from these studies, but few examples of interactions have been adequately replicated. In this review we introduce the topics of population genetics and gene x environment interaction research. We also provide a systematic review of the published literature on gene x lifestyle (physical activity and dietary factors) and gene x drug interactions in relation to obesity. Finally, we overview the scope and findings from these studies and discuss some of their strengths and limitations.

Do different production environments justify separate maize breeding programs?

Different production environments are being adopted by farmers. Therefore, allocation of resources to breeding research that targets different production environments should be continuously assessed. Agronomists should conduct extensive hybrid × production environment interaction research before recommending breeders to conduct separate breeding programs for each production environment. The lack of interactions between genotypes and production environments (e.g., tillage) would not justify conducting separate breeding programs and duplicating breeding resources. On the other hand, separate breeding programs would be necessary if cultivar rankings differ. The purpose of this paper is to review the available literature on experiments designed to test genotype × tillage interactions (GT) in maize (Zeamays L.). No-till system (NT) and conventional till system (CT) were utilized as examples of different production environments. The majority of experiments reviewed showed that there is no need to develop cultivars specific to NT because the cultivars that were developed under CT systems performed relatively the same under NT. The magnitude of GT interactions found was very small to expect better cultivars from breeding under NT. Additional research is needed to confirm these conclusions, especially when applied to other production environments (e.g., development of cultivars under organic conditions). Scientists should evaluate genotype by tillage interactions before investing additional resources in breeding for those specific target environments. Top yielding genotypes seem be consistent across years, locations, inputs; and most of the present evidence suggests that breeding for specific till systems is not necessary.

Segregation and Fragmentation: Extending Landscape Ecology and Pattern Metrics Analysis to Spatial Demography

Though demography’s roots involve a strong spatial component, recent attention to capitalizing on widely available spatially referenced demographic data has returned the focus to spatially enabled analyses. Landscape ecology offers a theoretical framework and concomitant methodology in pattern metric analysis well suited for extracting process through the examination of spatial patterns. Applied on the environmental side of population–environment interaction research, pattern metric analysis has not been brought to bear on population data per se. This research illustrates the utility of a pattern metric approach utilizing U.S. Census data from 1990 and 2000 to document changes in spatial configuration of race and class in South Carolina. The results corroborate similar findings elsewhere of exurban growth as well as an increasing income gap and spread of Hispanic population, both statistically and spatially. Further insight into the forces related to these processes is gained from explicit assessment of spatial configuration. The method is offered as a complementary tool to the richly evolving field of spatial demography.

Gene–environment interactions reexamined: Does mother's marital stability interact with the dopamine receptor D2 gene in the etiology of childhood attention-deficit/hyperactivity disorder?

Potential candidate Gene x Environment interactions in the etiology of childhood attention-deficit/hyperactivity disorder (ADHD) are examined between the dopamine receptor D2 gene (DRD2) and putative family environmental risk factors that reflect mothers' marital stability. Specifically, interactions were tested between DRD2 and mothers' marital status, number of marriages or cohabiting relationships, and age at first marriage. Moderate relations were found among the marital stability measures, and mother's marital status and number of marriages or cohabiting relationships (but not age at first marriage) were risk factors for their children's ADHD. All three mother's marital stability variables were associated with either the child's or mother's DRD2 genotypes. Gene x Environment interactions were found for children's ADHD diagnoses between children's DRD2 genotypes and mother's marital status and number of marriages or cohabiting relationships. It is of interest that these interactions were strengthened with the progressive addition of sets of covariates intended to control for alternative causal pathways that represent background genetic and environmental context confounds. The present findings highlight the importance of considering both the nexus of putative environmental risk factors and whether their etiology and effects are truly environmental in future Gene x Environment interaction research.