Human behavioural genetics of cognitive abilities and disabilities

Although neither the genome nor the environment can be manipulated in research on human behaviour, some of the new tools of molecular genetics can be brought to bear on human behavioural disorders (e.g. cognitive disabilities) and quantitative traits (e.g. cognitive abilities). The inability to manipulate the human genome experimentally has had the positive effect of focusing attention on naturally occuring genetic variation responsible for behavioural differences among individuals in all their complex multifactorial splendour. Genes in such complex multiple-gene systems are called quantitative trait loci (QTLs), which merge the two worlds of genetic research, quantitative genetics and molecular genetics. Although most genetic research on complex human behaviour has focused on severe mental disorders, cognitive abilities and disabilities may be even more immediately relevant to neuroscience. For example, verbal ability and spatial ability are two of the most heritable cognitive abilities, and reading disability is the first behavioural disability for which replicated QTL linkage has been found. The purpose of this essay is to provide an overview of the genetics of cognitive abilities and disabilities as an example of the impending merger of quantitative genetics and molecular genetics in QTL analysis of complex traits.     

Quantitative genetics of behavioural reaction norms: genetic correlations between personality and behavioural plasticity vary across stickleback populations

Behavioural ecologists have proposed various evolutionary mechanisms as to why different personality types coexist. Our ability to understand the evolutionary trajectories of personality traits requires insights from the quantitative genetics of behavioural reaction norms. We assayed > 1000 pedigreed stickleback for initial exploration behaviour of a novel environment, and subsequent changes in exploration over a few hours, representing their capacity to adjust their behaviour to changes in perceived novelty and risk. We found heritable variation in both the average level of exploration and behavioural plasticity, and population differences in the sign of the genetic correlation between these two reaction norm components. The phenotypic correlation was not a good indicator of the genetic correlation, implying that quantitative genetics are necessary to appropriately evaluate evolutionary hypotheses in cases such as these. Our findings therefore have important implications for future studies concerning the evolution of personality and plasticity.     

Frameworks of population obesity and the use of cultural consensus modeling in the study of environments contributing to obesity

Obesity in Eastern Europe has been linked to privilege and status prior to the collapse of communism, and to exposure to free-market economics after it. Neither formulation is a complete explanation, and it is useful to examine the potential value of other models of population obesity for the understanding of this phenomenon. These include those of: thrifty genotypes; obesogenic behaviour; obesogenic environments; nutrition transition; obesogenic culture; and biocultural interactions of genetics, environment, behaviour and culture. At the broadest level, obesity emerges from the interaction of thrifty genotype with obesogenic environment. However, defining obesogenic environments remains problematic, especially in relation to sociocultural factors. Furthermore, since different identity groups may share different values concerning the obesogenicity of the environment, a priori assumptions about group homogeneity may lead to flawed interpretations of the importance of sociocultural factors in obesogenic environments. A new way to identify cultural coherence of groups and populations in relation to environments contributing to obesity is put forward here, that of cultural consensus modeling.     

Genetics of human behavior: problems, results and prospects

In this paper, the main problems of modern behaviour genetics of man are formulated and methods for their study proposed. As a result of the Mendelian analysis of some psychometric scales of personality inventories, a major-gene mode of inheritance is found for 20% of scales of three questionnaires: MMPI, 16 PF and the Pathocharacterologic Diagnostic Inventory (PDI). Perspectives of further studies in the field of human behaviour genetics are outlined.     

Optimality and evolutionary genetics: complementary procedures for evolutionary analysis in behavioural ecology

The concepts and tools of optimality and game theory are a major component of research in behavioural ecology. In contrast, the theory and practice of evolutionary, ecological, population and quantitative genetics have made less of an impact on those studying the evolution of animal behaviour. A more complete understanding of the evolution of behaviour can be achieved by pursuing research that combines optimality and genetics, thereby overcoming some of the limitations inherent in a single approach.     

Genetic contributions to behavioural diversity at the gene-environment interface

Recent work on behavioural variation within and between species has furthered our understanding of the genetic architecture of behavioural traits, the identities of relevant genes and the ways in which genetic variants affect neuronal circuits to modify behaviour. Here we review our understanding of the genetics of natural behavioural variation in non-human animals and highlight the implications of these findings for human genetics. We suggest that gene-environment interactions are central to natural genetic variation in behaviour and that genes affecting neuromodulatory pathways and sensory processing are preferred sites of naturally occurring mutations.     

Environment change, geographic migration and sickle cell anaemia

The classic model describing the interaction between sickle cell anaemia and malaria is one of the most notable achievements of population genetics. Nevertheless, only panmictic populations in steady environments have been studied theoretically to date. In this paper, environment change and geographic inhomogeneity are introduced. The rate of decrease of mutation after environment improvement is obtained. The kinetics of the spread of disease after the initial mutation, together with the genetic composition profile near the borders of malaria areas, are calculated. The results are compared with the empirical data on the mutation level in African and African-American populations. It is shown that the spread of disease and decrease in mutation are highly asymmetric: the mutation level increases exponentially and decreases much more slowly (as a power function). The mathematical and biological reasons for this behaviour are discussed.     

Growth and social interactions of wild and sea-ranched brown trout and their hybrids

A laboratory study of the social behaviour and growth performance of juvenile brown trout Salmo trutta of wild and sea-ranched origin and their crosses, indicated that the social behaviour of wild and sea-ranched fish differed. Male and female parents seemed to have a different impact on the juveniles. The category having wild mother and sea-ranched father were less aggressive, less active in general, but active in feeding, and therefore had higher growth rates. This pattern arose despite that the feeding rate and the motivation to first get a food item when food was provided did not differ between the groups of fish. Wild fish tended to be most aggressive. If sea-ranched and wild fish have different intrinsic (genetically based) 'life styles', the crosses between wild and sea-ranched fish indicate that there is likelihood for an introgression of genes adapted to hatchery environment into the genetics of wild conspecifics. This is particularly serious when hatchery-reared fish invades wild populations over many years.     

Gene or environment? Species-specific control of stomatal density and length

Stomatal characteristics are used as proxies of paleo-environment. Only a few model species have been used to study the mechanisms of genetic and environmental effects on stomatal initiation. Variation among species has not been quantified. In this paper, results from an in situ reciprocal transplant experiment along an elevation gradient in the northeast Tibetan Plateau are reported, in which the relative effects of genetics (original altitude) and environment (transplant altitude) on stomatal density (SD) and length (SL) were quantified. In Thalictrum alpinum, only the environment significantly influenced SD, with the variance component ([Formula: see text]) of the environment found to be much greater than that of genetics ([Formula: see text]) ([Formula: see text]). In Kobresia humillis, only genetics significantly influenced SD and SL, with the genetics variance component found to be greater than that of the environment ([Formula: see text], for SD). These results suggest that the extent to which genetics and the environment determine stomatal initiation and development is species-specific. This needs to be considered when studying genetic or environmental controls of stomatal initiation, as well as when SD and SL are used as proxies for ancient climate factors (e.g., CO(2) concentration).     

Polarization vision: Drosophila enters the arena

Two new studies introduce the power of Drosophila genetics to polarization vision, revealing distinct photoreceptor inputs to polarotactic behaviour mediated by dorsal and ventral eye regions.     

The behaviour and ecology of the zebrafish, Danio rerio

The zebrafish Danio rerio, is an important model organism in developmental genetics, neurophysiology and biomedicine, but little is known about its natural ecology and behaviour. It is a small, shoaling cyprinid, native to the flood-plains of the Indian subcontinent, where it is found in shallow, slow-flowing waters. Zebrafish are group spawners and egg scatterers, although females are choosy with respect to sites for oviposition and males defend territories around such sites. Laboratory studies of zebrafish behaviour have encompassed shoaling, foraging, reproduction, sensory perception and learning. These studies are reviewed in relation to the suitability of the zebrafish as a model for studies on cognition and learning, development, behavioural and evolutionary ecology, and behavioural genetics.     

Do xeric landscapes increase genetic divergence in aquatic ecosystems?

1. Previous investigations of the ecological genetics among amphipods in south-western U.S.A. suggested a xeric landscape promoted genetic divergence among passively dispersed freshwater invertebrates, thereby enhancing speciation events. We predicted that less divergence would occur among amphipod populations across similar geographic distances in mesic regions. 2. Eight Hyalella azteca populations were sampled along a 200-km transect in western Oregon, U.S.A. Genetic distances among populations were estimated from randomly amplified polymorphic DNA (RAPD). Genetic analyses indicated much less divergence among Oregon populations than among Arizona populations in an arid environment. 3. Behavioural observations support the genetic data: Oregon populations exhibit little differentiation in swimming behaviour, whereas Hyalella populations in Arizona exhibit extremes in swimming behaviour. 4. These results provide preliminary support for the hypothesis that a xeric landscape promotes genetic and behavioural divergence among amphipods. Many aquatic invertebrates classified as panmictic populations may encompass genetically distinct groups; those isolated by a xeric landscape are especially prone to diversification.     

Greenbeards in yeast: an undergraduate laboratory exercise to teach the genetics of cooperation

Recent years have seen a dramatic increase in our understanding of the social behaviour of microbes. Here, we take advantage of these developments to present an undergraduate laboratory exercise that uses the cooperative flocculating behaviour of yeast (Saccharomyces sp.) to introduce the concept of inclusive fitness and teach the genetics of cooperation. Students generate their own data using co-cultures of various yeast strains and perform statistical analyses to test whether kin selection or greenbeard effects determine the cooperative flocculating behaviour. The lab has run successfully for two consecutive years in a second year course with some 1, 200 students per year at the University of Toronto, Canada. We discuss the benefits of using microbes to teach social evolution, describe the set-up and learning outcomes of the laboratory exercise, and then outline possible extension and variants of the lab. In addition to providing students with the opportunity to use a model organism to study social behaviour, students are also taught common laboratory skills, such as replica plating and sterile techniques. Ultimately, while the genetics of cooperation has traditionally been taught through computer simulations and evolutionary games, this exercise demonstrates a way to experimentally introduce the topic.     

Science and society: applications of behavioural genetics: outpacing the science?

Human behavioural genetics is an established research discipline of the genomic age, and applications for behavioural genetic information are most likely to emerge in areas such as criminal justice, education, employment and insurance. However, behavioural genetic research into personality traits and antisocial behaviour poses several risks; for example, tentative or preliminary research findings might be misused in legal and commercial settings. Scientific caution, public and media education, expert consultation and confidentiality protection are essential for the responsible use of behavioural genetics.     

环境对果蝇P转座因子的作用关系研究

转座因子,重组、整合、遗传效应等是目前遗传学领域的一个研究热题。转座因子对遗传变异、宗系进化、突变频率、物种形成、新基因的产生以及对分子生物学、遗传工程学、群体遗传学和数量遗传学等方面的研究都有着重要的意义,主要对果蝇的P转座因子以及环境对P转座因子遗传效应的作用关系进行了研究。     

Learning genetics through an authentic research simulation in bioinformatics

Following the rationale that learning is an active process of knowledge construction as well as enculturation into a community of experts, we developed a novel web-based learning environment in bioinformatics for high-school biology majors in Israel. The learning environment enables the learners to actively participate in a guided inquiry process by solving a problem in the context of authentic research in genetics. Through the learning environment, the learners are exposed to a genetics problem which was developed on the basis of research in which a mutated gene, which causes deafness, was identified. They follow, step by step, the way scientists try to solve it, using the current geneticists' toolbox. The environment uses an adapted version of the BLAST program (a bioinformatics tool which enables to find similarities between sequences), which was modified in a way that enables the teachers and students to use it easily. Using quantitative and qualitative research approaches, we were able to show that learning through the bioinformatics environment promotes construction of new knowledge structures and influences students' acquisition of a deeper and multidimensional understanding of the genetics domain. In addition, learning through the bioinformatics environment influences students' comprehension of the practices and scientific ways of thinking.     

Experimental evidence that adult antipredator behaviour is heritable and not influenced by behavioural copying in a wild bird

Knowledge of the relative importance of genetics and behavioural copying is crucial to appraise the evolvability of behavioural consistencies. Yet, genetic and non-genetic factors are often deeply intertwined, and experiments are required to address this issue. We investigated the sources of variation of adult antipredator behaviour in the Alpine swift (Apus melba) by making use of long-term behavioural observations on parents and cross-fostered offspring. By applying an 'animal model' approach to observational data, we show that antipredator behaviour of adult Alpine swifts was significantly repeatable over lifetime (r = 0.273) and heritable (h(2) = 0.146). Regression models also show that antipredator behaviours differed between colonies and sexes (females were more tame), and varied with the hour and year of capture. By applying a parent-offspring regression approach to 59 offspring that were exchanged as eggs or hatchlings between pairs of nests, we demonstrate that offspring behaved like their biological parents rather than like their foster parents when they were adults themselves. Those findings provide strong evidence that antipredator behaviour of adult Alpine swifts is shaped by genetics and/or pre-hatching maternal effects taking place at conception but not by behavioural copying.     

A microcomputer method for recording and analysing behavioural elements

The trend in ethology, psychopharmacology and behaviour genetics is to get increasingly higher resolution of the behaviour of animals, since it increases the sensitivity of the tests used. Consequently the higher resolution requires an increased data-logging efficiency, and a decreased time-investment for data handling. In this paper a method for inexpensive microcomputers is presented, which enables an individual experimenter to obtain frequency, relative duration and its variance from as many behavioural elements as desired.     

果蝇求偶行为的影响因素及其分子基础

果蝇Drosophila melanogaster Meigen是进行行为遗传学研究的极好材料。果蝇的雄性求偶行为已经被作为行为遗传学研究的模式。文章简要介绍近年来在遗传和分子水平上对果蝇性信息素和求偶行为的研究进展,尤其是突变体在果蝇行为遗传学研究中的应用。通过对果蝇求偶行为的分析,分别介绍果蝇的性信息素及视觉、听觉、嗅觉和味觉相关基因在果蝇求偶和交配行为过程中的作用。     

Experimental evidence for adaptive personalities in a wild passerine bird

Individuals of the same species differ consistently in risky actions. Such ‘animal personality’ variation is intriguing because behavioural flexibility is often assumed to be the norm. Recent theory predicts that between-individual differences in propensity to take risks should evolve if individuals differ in future fitness expectations: individuals with high long-term fitness expectations (i.e. that have much to lose) should behave consistently more cautious than individuals with lower expectations. Consequently, any manipulation of future fitness expectations should result in within-individual changes in risky behaviour in the direction predicted by this adaptive theory. We tested this prediction and confirmed experimentally that individuals indeed adjust their ‘exploration behaviour’, a proxy for risk-taking behaviour, to their future fitness expectations. We show for wild great tits (Parus major) that individuals with experimentally decreased survival probability become faster explorers (i.e. increase risk-taking behaviour) compared to individuals with increased survival probability. We also show, using quantitative genetics approaches, that non-genetic effects (i.e. permanent environment effects) underpin adaptive personality variation in this species. This study thereby confirms a key prediction of adaptive personality theory based on life-history trade-offs, and implies that selection may indeed favour the evolution of personalities in situations where individuals differ in future fitness expectations.