Complex Behavioral Traits Research Articles

Epistasis between 5-HTTLPR and ADRA2B polymorphisms influences attentional bias for emotional information in healthy volunteers

Individual differences in emotional processing are likely to contribute to vulnerability and resilience to emotional disorders such as depression and anxiety. Genetic variation is known to contribute to these differences but they remain incompletely understood. The serotonin transporter (5-HTTLPR) and α2B-adrenergic autoreceptor (ADRA2B) insertion/deletion polymorphisms impact on two separate but interacting monaminergic signalling mechanisms that have been implicated in both emotional processing and emotional disorders. Recent studies suggest that the 5-HTTLPR s allele is associated with a negative attentional bias and an increased risk of emotional disorders. However, such complex behavioural traits are likely to exhibit polygenicity, including epistasis. This study examined the contribution of the 5-HTTLPR and ADRA2B insertion/deletion polymorphisms to attentional biases for aversive information in 94 healthy male volunteers and found evidence of a significant epistatic effect (p<0.001). Specifically, in the presence of the 5-HTTLPR s allele, the attentional bias for aversive information was attenuated by possession of the ADRA2B deletion variant whereas in the absence of the s allele, the bias was enhanced. These data identify a cognitive mechanism linking genotype-dependent serotonergic and noradrenergic signalling that is likely to have implications for the development of cognitive markers for depression/anxiety as well as therapeutic drug effects and personalized approaches to treatment.

Genetic Dissection of Behavioral Flexibility: Reversal Learning in Mice

Behavioral inflexibility is a feature of schizophrenia, attention-deficit/hyperactivity disorder, and behavior addictions that likely results from heritable deficits in the inhibitory control over behavior. Here, we investigate the genetic basis of individual differences in flexibility, measured using an operant reversal learning task. We quantified discrimination acquisition and subsequent reversal learning in a cohort of 51 BXD strains of mice (2-5 mice/strain, n = 176) for which we have matched data on sequence, gene expression in key central nervous system regions, and neuroreceptor levels. Strain variation in trials to criterion on acquisition and reversal was high, with moderate heritability (∼.3). Acquisition and reversal learning phenotypes did not covary at the strain level, suggesting that these traits are effectively under independent genetic control. Reversal performance did covary with dopamine D2 receptor levels in the ventral midbrain, consistent with a similar observed relationship between impulsivity and D2 receptors in humans. Reversal, but not acquisition, is linked to a locus on mouse chromosome 10 with a peak likelihood ratio statistic at 86.2 megabase (p < .05 genome-wide). Variance in messenger RNA levels of select transcripts expressed in neocortex, hippocampus, and striatum correlated with the reversal learning phenotype, including Syn3, Nt5dc3, and Hcfc2. This work demonstrates the clear trait independence between, and genetic control of, discrimination acquisition and reversal and illustrates how globally coherent data sets for a single panel of highly related strains can be interrogated and integrated to uncover genetic sources and molecular and neuropharmacological candidates of complex behavioral traits relevant to human psychopathology.

Neuroimmune regulation of alcohol consumption: behavioral validation of genes obtained from genomic studies

Analysis of mouse brain gene expression, using strains that differ in alcohol consumption, provided a number of novel candidate genes that potentially regulate alcohol consumption. We selected six genes [beta-2-microglobulin (B2m), cathepsin S (Ctss), cathepsin F (Ctsf), interleukin 1 receptor antagonist (Il1rn), CD14 molecule (Cd14) and interleukin 6 (Il6)] for behavioral validation using null mutant mice. These genes are known to be important for immune responses but were not specifically linked to alcohol consumption by previous research. Null mutant mice were tested for ethanol intake in three tests: 24-hour two-bottle choice, limited access two-bottle choice and limited access to one bottle of ethanol. Ethanol consumption and preference were reduced in all the null mutant mice in the 24-hour two-bottle choice test, the test that was the basis for selection of these genes. No major differences were observed in consumption of saccharin or quinine in the null mutant mice. Deletion of B2m, Ctss, Il1rn, Cd14 and Il6 also reduced ethanol consumption in the limited access two bottle choice test for ethanol intake; with the Il1rn and Ctss null mutants showing reduced intake in all three tests (with some variation between males and females). These results provide the most compelling evidence to date that global gene expression analysis can identify novel genetic determinants of complex behavioral traits. Specifically, they suggest a novel role for neuroimmune signaling in regulation of alcohol consumption.

A systems genetic analysis of alcohol drinking by mice, rats and men: Influence of brain GABAergic transmission

Genetic influences on the predisposition to complex behavioral or physiological traits can reflect genetic polymorphisms that lead to altered gene product function, and/or variations in gene expression levels. We have explored quantitative variations in an animal’s alcohol consumption, using a genetical genomic/phenomic approach. In our studies, gene expression is correlated with amount of alcohol consumed, and genomic regions that regulate the alcohol consumption behavior and the quantitative levels of gene expression (behavioral and expression quantitative trait loci [QTL]) are determined and used as a filter to identify candidate genes predisposing the behavior. We determined QTLs for alcohol consumption using the LXS panel of recombinant inbred mice. We then identified genes that were: 1) differentially expressed between five high and five low alcohol-consuming lines or strains of mice; and 2) were physically located in, or had an expression QTL (eQTL) within the alcohol consumption QTLs. Comparison of mRNA and protein levels in brains of high and low alcohol consuming mice led us to a bioinformatic examination of potential regulation by microRNAs of an identified candidate transcript, Gnb1 ( G protein beta subunit 1). We combined our current analysis with our earlier work identifying candidate genes for the alcohol consumption trait in mice, rats and humans. Our overall analysis leads us to postulate that the activity of the GABAergic system, and in particular GABA release and GABA receptor trafficking and signaling, which involves G protein function, contributes significantly to genetic variation in the predisposition to varying levels of alcohol consumption. This article is part of a Special Issue entitled ‘Trends in Neuropharmacology: In Memory of Erminio Costa’.

Aggressivity, Violence, Sociability and Conflict Resolution: What Genes Can Tell Us

Conflicts are inherent to the human condition, as they are for all living beings. Disputes about resources or access to mating partners are among the most common causes of conflict. Conflict is herein defined as a struggle or contest between individuals or parties, and may involve a variety of aggressive behaviours. In humans, aggressiveness, violence and conflicts, including individual predisposal to conflict resolution, have traditionally been said to have deep cultural roots, but recent research in both neuroscience and genetics has shown the influence of genes on such complex behavioural traits. In this paper, recent data on the genetic aspects of these interrelated behaviours will be put together, including the effects of particular genes, the influence of stress and gender on gene regulation, and gene–environment interactions, all of which may influence biological predisposal to conflict resolution. Other genetically influenced behavioural aspects involved in conflicts and conflict resolution, such as sociability, will also be discussed. The importance of taking into account genetic and biological data to provide strategies for conflict resolution will be highlighted.

Behavioral characterization of A/J and C57BL/6J mice using a multidimensional test: Association between blood plasma and brain magnesium-ion concentration with anxiety

Up to 29% of all adults will experience an anxiety-related disorder during their lives. Treatment of these disorders is still difficult and the exact mechanisms and pathways behind anxiety disorders remain to be elucidated. Although evidence exists for genetically based susceptibility of human psychiatric diseases, risk genes have rarely been identified up to now. Inbred mouse strains are, together with the crosses and genetic reference populations derived from them, important tools for the genetic dissection of complex behavioral traits in the mouse. Thus, inbred mouse models of human anxiety may be a potent starting tool to search for candidate genes in mice, which could then via comparative genomics be translated to the human situation. In this paper we investigate whether the A/J and C57BL/6J mouse inbred strains differ in a limited number of motivational systems (anxiety, exploration, memory, locomotion, and social affinity), but especially in anxiety-related behavior from each other. Young adult individuals from both genders of A/J and C57BL/6J strains were behaviorally phenotyped using a multidimensional test: the modified hole board. This paradigm basically is a combination of the traditional hole board and the open field test allowing to test for anxiety-related avoidance behavior, risk assessment, arousal, exploration, memory, locomotor activity, and social affinity, using just one single test. An acute, aversive stimulus (intra-peritoneal injection with saline) was applied to the animals to test for the robustness of their behavioral phenotype. In addition, presumed physiological indicators for anxiety (circulating glucose, cholesterol, and corticosterone, adrenal tyrosine hydroxylase, and blood plasma and brain magnesium) were investigated. It could be concluded that C57BL/6J and A/J mice differ with respect to almost all tested motivational systems. For some measures, including anxiety-related behavioral parameters, there were clear gender effects. The high-anxiety phenotype of A/J mice could be shown to represent a primary and robust characteristic. Further, blood plasma and brain magnesium levels were significantly correlated with several anxiety-related behavioral parameters. These results emphasize the hypothesized, and possibly causal, association between magnesium status and emotionality.

Genetics of personalities: no simple answers for complex traits

Identifying the genes that underlie phenotypic variation in natural populations, and assessing the consequences of polymorphisms at these loci for individual fitness are major objectives in evolutionary biology. Yet, with the exception of a few success stories, little progress has been made, and our understanding of the link between genotype and phenotype is still in its infancy. For example, although body length in humans is largely genetically determined, with heritability estimates greater than 0.8, massive genome-wide association studies (GWAS) have only been able to account for a very small proportion of this variation (Gudbjartsson et al. 2008). If it is so difficult to explain the genetics behind relatively 'simple' traits, can we envision that it will at all be possible to find genes underlying complex behavioural traits in wild non-model organisms? Some notable examples suggest that this can indeed be a worthwhile endeavour. Recently, the circadian rhythm gene Clock has been associated with timing of breeding in a wild blue tit population (Johnsen et al. 2007; Liedvogel et al. 2009) and the Pgi gene to variation in dispersal and flight endurance in Glanville fritillary butterflies (Niitepold et al. 2009). A promising candidate gene for influencing complex animal personality traits, also known as behavioural syndromes (Sih et al. 2004), is the dopamine receptor D4 (DRD4) gene. Within the last decade, polymorphisms in this gene have been associated with variation in novelty seeking and exploration behaviour in a range of species, from humans to great tits (Schinka et al. 2002; Fidler et al. 2007). In this issue, Korsten et al. (2010) attempt to replicate this previously observed association in wild-living birds, and test for the generality of the association between DRD4 and personality across a number of European great tit populations.

The effects of foraging role and genotype on light and sucrose responsiveness in honey bees ( Apis mellifera L.)

In honey bees, the sensory system can be measured by touching sugar water to the antennae, eliciting the extension of the proboscis. The proboscis extension response (PER) [6,13] is closely associated with complex behavioral traits involving foraging and learning [30–32,34–36,43–49]. Bees specializing in pollen foraging are more responsive to low concentrations of sucrose solution and, as a consequence, perform better in associative learning assays [4,43,46–48]. An important unanswered question is whether sensory-motor differences between pollen and nectar specialists are restricted to the gustatory modality or whether pollen foragers are in general more sensitive to sensory stimuli associated with foraging. We used an assay designed to test responsiveness to varying intensities of light [11] and tested responsiveness to varying concentrations of sucrose in wild-type pollen and non-pollen foragers and bees artificially-selected for differences in pollen-hoarding behavior [27]. Workers of the high pollen-hoarding strain are more likely to specialize on collecting pollen. In wild-type bees, pollen foragers were more responsive to sucrose and light than non-pollen foragers. In the selected strains, high pollen-hoarding pre-foragers were more responsive to sucrose and light than low pollen-hoarding pre-foragers. These PER and light assays demonstrate a positive relationship between the gustatory and visual sensory modalities with respect to foraging behavior and genotype. We propose that light responsiveness, in addition to sucrose responsiveness, is a component of a pollen-hoarding behavioral syndrome – a suite of traits that covary with hoarding behavior [51,52] – previously described for honey bees [14,37,41]. We suggest that the modulation of the sensory system may be partially constrained by the interdependent modulation of multiple sensory modalities associated with hoarding and foraging.

The Neurobiology of Individual Differences in Complex Behavioral Traits

Neuroimaging, especially BOLD fMRI, has begun to identify how variability in brain function contributes to individual differences in complex behavioral traits. In parallel, pharmacological fMRI and multimodal PET/fMRI are identifying how variability in molecular signaling pathways influences individual differences in brain function. Against this background, functional genetic polymorphisms are being utilized to understand the origins of variability in signaling pathways as well as to model efficiently how such emergent variability impacts behaviorally relevant brain function. This article provides an overview of a research strategy seeking to integrate these complementary technologies and utilizes existing empirical data to illustrate its effectiveness in illuminating the neurobiology of individual differences in complex behavioral traits. The article also discusses how such efforts can contribute to the identification of predictive markers that interact with environmental factors to precipitate disease and to develop more effective and individually tailored treatment regimes.

The Honeybee Apis mellifera

INTRODUCTIONHoneybees (Apis mellifera) are distributed throughout the world and have a critical role in the pollination of crops and pasture. Honeybees have an intricate social structure and display complex behavioral traits such as sociality, language, division of labor, and exceptional feats of learning and memory. Honeybees also exhibit polyphenism, whereby the females can either develop as workers or as morphologically distinct, reproductively active queens. Although historical studies of honeybee biology have been performed, the recent advent of the genome sequence and a number of other modern tools have made dissection of the molecular details of this remarkable insect possible.

Birdsong “Transcriptomics”: Neurochemical Specializations of the Oscine Song System

BackgroundVocal learning is a rare and complex behavioral trait that serves as a basis for the acquisition of human spoken language. In songbirds, vocal learning and production depend on a set of specialized brain nuclei known as the song system.Methodology/Principal FindingsUsing high-throughput functional genomics we have identified ∼200 novel molecular markers of adult zebra finch HVC, a key node of the song system. These markers clearly differentiate HVC from the general pallial region to which HVC belongs, and thus represent molecular specializations of this song nucleus. Bioinformatics analysis reveals that several major neuronal cell functions and specific biochemical pathways are the targets of transcriptional regulation in HVC, including: 1) cell-cell and cell-substrate interactions (e.g., cadherin/catenin-mediated adherens junctions, collagen-mediated focal adhesions, and semaphorin-neuropilin/plexin axon guidance pathways); 2) cell excitability (e.g., potassium channel subfamilies, cholinergic and serotonergic receptors, neuropeptides and neuropeptide receptors); 3) signal transduction (e.g., calcium regulatory proteins, regulators of G-protein-related signaling); 4) cell proliferation/death, migration and differentiation (e.g., TGF-beta/BMP and p53 pathways); and 5) regulation of gene expression (candidate retinoid and steroid targets, modulators of chromatin/nucleolar organization). The overall direction of regulation suggest that processes related to cell stability are enhanced, whereas proliferation, growth and plasticity are largely suppressed in adult HVC, consistent with the observation that song in this songbird species is mostly stable in adulthood.Conclusions/SignificanceOur study represents one of the most comprehensive molecular genetic characterizations of a brain nucleus involved in a complex learned behavior in a vertebrate. The data indicate numerous targets for pharmacological and genetic manipulations of the song system, and provide novel insights into mechanisms that might play a role in the regulation of song behavior and/or vocal learning.

A 7 Mb duplication at 22q13 in a girl with bipolar disorder and hippocampal malformation

We identified a duplication of 22q13.1-q13.2 in a 10-year-old girl and demonstrated that this duplication was the recombinant product of a maternal intrachromosomal insertion. Phenotypic characteristics included prominent forehead, small low-set ears, hypertelorism, epicanthal folds, small palpebral fissures, short philtrum, and syndactyly. MRI of the brain revealed high signal abnormalities in the periventricular white matter, a hypoplastic corpus callosum, under-rotated hippocampus on the left and atrophic hippocampus on the right. Since age 5, the child's behavior has shown cyclic maniacal episodes with severely disorganized mood and behavior. Psychiatric and cognitive assessment led to a diagnosis of bipolar disorder not otherwise specified, manic episodes, attention deficit hyperactivity disorder and moderate mental retardation. Array-CGH revealed an interstitial duplication of 6.9 Mb at chromosome 22q: dup(22)(q13.1q13.2). FISH using BAC clones confirmed the array-CGH results and demonstrated that the duplication was inverted. G-banding analysis in the proposita's mother revealed a banding pattern suggestive of an intrachromosomal insertion, as demonstrated by dual-color FISH with BACs that were duplicated in the proposita and multicolor-banding (MCB) based on microdissection derived region-specific libraries for chromosome 22. Our findings suggest that in both seemingly de novo deletions and duplications, the parent transmitting the imbalance should be investigated for possible balanced rearrangements. This report reinforces previous evidence that chromosome imbalances, and thus gene dosage effects, may be at the basis of some psychiatric disorders. Stringent correlations between submicroscopic imbalances, specific behavioral phenotypes and brain imaging will possibly help in dissecting complex behavioral traits.

A genome-wide panel of congenic mice reveals widespread epistasis of behavior quantitative trait loci

Understanding the genetics of behavioral variation remains a fascinating but difficult problem with considerable theoretical and practical implications. We used the genome-tagged mice (GTM) and an extensive test battery of well-validated behavioral assays to scan the genome for behavioral quantitative trait loci (QTLs). The GTM are a panel of 'speed congenic' mice consisting of over 60 strains spanning the entire autosomal genome. Each strain harbors a small (approximately 23 cM) DBA/2J donor segment on a uniform C57BL/6J background. The panel allows for mapping to regions as small as 5 cM and provides a powerful new tool for increasing mapping power and replicability in the analysis of QTLs. A total of 97 loci were mapped for a variety of complex behavioral traits including hyperactivity, anxiety, prepulse inhibition, avoidance and conditional fear. A larger number of loci were recovered than generally attained from standard mapping crosses. In addition, a surprisingly high proportion of loci, 63%, showed phenotypes unlike either of the parental strains. These data suggest that epistasis decreases sensitivity of locus detection in traditional crosses and demonstrate the utility of the GTM for mapping complex behavioral traits with high sensitivity and precision.

A quantitative trait locus for variation in dopamine metabolism mapped in a primate model using reference sequences from related species.

Non-human primates (NHP) provide crucial research models. Their strong similarities to humans make them particularly valuable for understanding complex behavioral traits and brain structure and function. We report here the genetic mapping of an NHP nervous system biologic trait, the cerebrospinal fluid (CSF) concentration of the dopamine metabolite homovanillic acid (HVA), in an extended inbred vervet monkey (Chlorocebus aethiops sabaeus) pedigree. CSF HVA is an index of CNS dopamine activity, which is hypothesized to contribute substantially to behavioral variations in NHP and humans. For quantitative trait locus (QTL) mapping, we carried out a two-stage procedure. We first scanned the genome using a first-generation genetic map of short tandem repeat markers. Subsequently, using >100 SNPs within the most promising region identified by the genome scan, we mapped a QTL for CSF HVA at a genome-wide level of significance (peak logarithm of odds score >4) to a narrow well delineated interval (<10 Mb). The SNP discovery exploited conserved segments between human and rhesus macaque reference genome sequences. Our findings demonstrate the potential of using existing primate reference genome sequences for designing high-resolution genetic analyses applicable across a wide range of NHP species, including the many for which full genome sequences are not yet available. Leveraging genomic information from sequenced to nonsequenced species should enable the utilization of the full range of NHP diversity in behavior and disease susceptibility to determine the genetic basis of specific biological and behavioral traits.

Breeding behaviour and hybridization: variation in male chorusing behaviour promotes mating among taxa in waterfrogs

Identifying the proximate basis of heterospecific matings in hybrid populations could significantly advance our understanding of mate recognition. As females are often considered to be the more selective sex, most studies have focused only on female mate choice. However, male behaviour often plays a determinant role in sexual selection. In the European waterfrog hybridization complex, the unbalanced mating frequency observed between hybrid females Rana esculenta and the parental species Rana lessonae has been attributed to a preference of these females for heterospecific males. In this study, for the first time we investigated the behaviour of males from three taxa (two parental species and the hybrid) in natural choruses. It appears that the three waterfrog taxa differ in their mating behaviour. We found that the breeding behaviour of R. lessonae males (i.e. low-frequency territorial call, close intermale proximity, movement not limited to a small area) suggests that they do not defend any territory. This constitutes evidence that R. lessonae males compete to outrace rivals to receptive females. Apart from the acoustic behaviour that appears to be intermediate between that of the two parental species, the other behavioural traits of the hybrid resemble those of the parental species Rana ridibunda (aggressive and territorial behaviours). These results suggest a genetic basis to these complex behavioural traits. From an ecological point of view, we conclude that the strong under-representation of hybrid males observed in amplexus can be due to the maladaptive hybrid reproductive tactic in mixed choruses.

Behavioral syndromes and the evolution of correlated behavior in zebrafish

Studies of “behavioral syndromes” in different populations and species of animals can be used to shed light on the underlying mechanisms of evolution. For example, some personality syndromes suggest the existence of an underlying hormonal link, whereas other relationships between boldness and aggression appear to be the result of similar selective pressures. Here, we used 1 wild-derived and 2 laboratory strains of zebrafish (Danio rerio) to examine relationships among 5 behavioral measures: shoaling, activity level, predator approaches, latency to feed after a disturbance, and biting to a mirror stimulus. We found evidence of an activity syndrome, as if underlying metabolic costs influence variation in multiple forms of behavior. Evidence for a relationship between boldness and aggression was also apparent but depended both on strain and which specific behavior patterns were identified as measures of “boldness.” Although some comparisons of laboratory and wild-derived strains were consistent with a domestication syndrome, others were not. Most observed relationships were relatively weak and occasionally inconsistent, arguing against strong underlying genetic linkages or pleiotropic effects relating any of the behavioral measures. Instead, it may be more important to study the details of selective context or the long-term impact of linkages between some, but not all, of a large set of genes influencing complex behavioral traits. We found profound differences among strains in most behavior patterns, but few sex differences. One strain (TM1) was consistently different from the others (SH and Nadia) being more social, more likely to approach predators, and taking less time to recover from disturbance than were the other 2 strains.

Behavior of Remipedia in the Laboratory, with Supporting Field Observations

We observed in the laboratory the behavior of six individuals of an as yet undescribed species of Speleonectes (Remipedia) over a period of 76 days. The live specimens were collected from an anchialine cave on the Yucatan Peninsula and maintained in separate aquaria at the Zoological Museum Amsterdam. In addition, field observations were conducted in the same cave to compare the laboratory results with naturally occurring behaviors. We found a variety of complex behavioral traits that include several new and unexpected findings. For example, our observations suggest that remipedes are not obligatory, but rather facultative carnivores, and that filtering particles might be the predominant mode of feeding. A digital video with examples of various behavioral traits can be downloaded at http://www. tiho-hannover.de/einricht/botanik/research.htm.

Why do young women smoke? II. Role of traumatic life experience, psychological characteristics and serotonergic genes

Cigarette smoking is a complex behavioral phenotype to which environmental, psychological and genetic factors contribute. The purpose of this study was to investigate these multifactorial effects with a specific focus on young women and on genes that encode serotonin (5-HT) receptors and the 5-HT transporter. A case-control sample of female Israeli college students provided comprehensive background data and details of cigarette smoking and completed a battery of psychological instruments. They were divided into smoking initiators (SI, n=242) or non-initiators (NI, n=148); SI were further subdivided into high (HND, n=127) and low nicotine-dependent smokers (LND, n=115) on the basis of their scores on the Fagerstrom Tolerance Questionnaire (FTQ). Single-nucleotide polymorphisms (SNPs) in five serotonin receptor genes (HTR1A, HTR1B, HTR2A, HTR2C and HTR6) and the 5-HT transporter-linked polymorphic region (5-HTTLPR) were genotyped. In a logistic regression model for SI (chi2=117.90, P=1.6 x 10(-19), Nagelkerke R2=0.42), novelty seeking (odds ratio (OR)=1.134, P=0.00009) was a significant risk factor. A five SNP CACCC haplotype in HTR6 was a strong protective factor against SI (OR=0.26; P=0.007). The interaction of HTR6-C276T genotype and lifetime traumatic experience contributed strongly to the risk of SI (OR=13.88, P=0.0001). Specifically, subjects homozygous for the HTR6-C276T C allele showed significantly increased risk of SI if they had experienced trauma. Although significant (chi2=42.85, P=1.00 x 10(-7)), the best-fitting model for ND was less predictive than the model for SI (Nagelkerke R2=0.24). HTR1B-G861C GG genotype (OR=2.29, P=0.01) was a significant risk factor for HND. Further studies should consider the interactive contribution of life events and relevant gene variants to cigarette smoking and other complex behavioral traits.

Variation in Anti-Predator Behavior Among Five Strains of Inbred Guppies, Poecilia reticulata

Quantitative genetic studies frequently utilize inbred strains of animals as tools for partitioning the direct and indirect effects of genes from environmental effects in generating an observed phenotype, however, this approach is rarely applied to behavioral studies. Guppies, Poecilia reticulata, perform a set of anti-predator behaviors that may provide an ideal system to study how complex behavioral traits are generated. To assess the utility of ornamental guppies in quantitative genetics studies of behavior, we assayed five morphologically distinct strains of ornamental guppies for response to predator cues and for variation in response among strains. Despite individual variation, all five strains responded to predator cues and differences among strains were found for all assayed behaviors, including measures of boldness and predator avoidance.

Transcriptional response to alcohol exposure in Drosophila melanogaster

Whole-genome transcriptional analysis following alcohol exposure in flies identifies key enzymes in conserved metabolic pathways that may contribute to human alcohol sensitivity.