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Evolutionary adaptationism: another biological approach to criminal and antisocial behaviour.

Although in a sense "genetic', the conceptual framework of evolutionary psychology, behavioural ecology and sociobiology is distinct from that of behaviour genetics. Considerable confusion has resulted from failures to recognize the distinctions. These disciplines are primarily concerned with the characterization of evolved adaptations, which are usually species-typical and environmentally contingent, so theory and research in these fields mainly concerns environmental rather than genetic sources of behavioural variation. Heritable behavioural variation is in general neither predicted by nor supportive of adaptationist theories. One might even say that substantial heritability of an apparently consequential attribute is a datum that challenges the tenets of adaptationism. Behaviour genetics and evolutionary adaptationism have had only limited mutual influence, but increasing knowledge of the processes by which genotypes affect behavioural phenotypes should facilitate development of a more synthetic approach.

Adaptation, Psychological↗

Behaviour modification by genetic intervention--the law's response.

The Human Genome Initiative has stimulated research worldwide into mankind's genetic structure. It has led to identifying and understanding the function of many genes which cause illnesses, deformities, organ malfunctions and, more recently, behavioural aberrations. The science of gene therapy has developed in tandem and has initiated therapeutic treatment by the replacement of defective genes in humans. In the legal sphere guidelines for the application of gene therapy have been recommended by the Council of Europe, the United Kingdom, France, Denmark and the United States amongst others. South Africa has adopted the guidelines of the American National Institutes of Health. It is however submitted that third world countries such as South Africa have many other more basic health care problems on which to spend their limited resources despite having the technology to practise gene therapy.

Advisory Committees↗

Genetics of social behaviour in fire ants.

A recent study is the first to sequence a gene known to underlie a complex social phenotype. In the fire ant, Solenopsis invicta, a single allelic difference at the Gp-9 locus specifies the number of queens a colony has, and hence the social structure of the colony. Gp-9 appears to encode a protein implicated in chemical recognition of nestmates, consistent with workers determining queen number by selectively executing queens as a function of workers' and queens' Gp-9 genotypes. Other Solenopsis species exhibit the same social and genetic polymorphism. This study pioneers the integrated understanding of the evolution of social behaviour at molecular, individual and social levels.

Animals↗

Inclusive fitness arguments in genetic models of behaviour.

My purpose here is to provide a coherent account of inclusive fitness techniques, accessible to a mathematically literate graduate student in evolutionary biology, and to relate these to standard one-locus genetic models. I begin in Sect. 2 with a general formulation of evolutionary stability; in Sect. 3 and Sect. 4 I interpret the basic stability conditions within genetic and inclusive fitness models. In Sect. 5 I extend these concepts to the case of a class-structured population, and in Sect. 6 I illustrate these notions with a sex ratio example. In Sect. 7 I give a proof of the result that under additive gene action and weak selection, an inclusive fitness argument is able to verify an important stability condition (2.5) for one-locus genetic models. Most of these results have been published.

Alleles↗

Colony structure in a plant-ant: behavioural, chemical and genetic study of polydomy in Cataulacus mckeyi (Myrmicinae).

Social organisation of colonies of obligate plant-ants can affect their interaction with myrmecophyte hosts and with other ants competing for the resources they offer. An important parameter of social organisation is whether nest sites of a colony include one or several host individuals. We determined colony boundaries in a plant-ant associated with the rainforest understorey tree Leonardoxa africana subsp. africana, found in coastal forests of Cameroon (Central Africa). This myrmecophyte is strictly associated with two ants, Petalomyrmex phylax and Cataulacus mckeyi. Plants provide food and nesting sites for P. phylax, which protects young leaves against insect herbivores. This mutualism is often parasitised by C. mckeyi, which uses but does not protect the host. The presence of C. mckeyi on a tree excludes the mutualistic ant. Because Petalomyrmex-occupied trees are better protected, their growth and survival are superior to those of Cataulacus-occupied trees, giving P. phylax an advantage in occupation of nest sites. C. mckeyi often colonises trees that have lost their initial associate P. phylax, as a result of injury to the tree caused by disturbance. Polydomy may allow C. mckeyi to occupy small clumps of trees, without the necessity of claustral colony foundation in each tree. Investigating both the proximate (behavioural repertoire, colony odour) and the ultimate factors (genetic structure) that may influence colony closure, we precisely defined colony boundaries. We show that colonies of C. mckeyi are monogynous and facultatively polydomous, i.e. a colony occupies one to several Leonardoxa trees. Workers do not produce males. Thus, the hypothesis that polydomy allows workers in queenless nests to evade queen control for their reproduction is not supported in this instance. This particular colony structure may confer on C. mckeyi an advantage in short-distance dispersal, and this could help explain its persistence within the dynamic Leonardoxa system.

Adaptation, Physiological↗

Stress-induced variation in evolution: from behavioural plasticity to genetic assimilation.

Extreme environments are closely associated with phenotypic evolution, yet the mechanisms behind this relationship are poorly understood. Several themes and approaches in recent studies significantly further our understanding of the importance that stress-induced variation plays in evolution. First, stressful environments modify (and often reduce) the integration of neuroendocrinological, morphological and behavioural regulatory systems. Second, such reduced integration and subsequent accommodation of stress-induced variation by developmental systems enables organismal 'memory' of a stressful event as well as phenotypic and genetic assimilation of the response to a stressor. Third, in complex functional systems, a stress-induced increase in phenotypic and genetic variance is often directional, channelled by existing ontogenetic pathways. This accounts for similarity among individuals in stress-induced changes and thus significantly facilitates the rate of adaptive evolution. Fourth, accumulation of phenotypically neutral genetic variation might be a common property of locally adapted and complex organismal systems, and extreme environments facilitate the phenotypic expression of this variance. Finally, stress-induced effects and stress-resistance strategies often persist for several generations through maternal, ecological and cultural inheritance. These transgenerational effects, along with both the complexity of developmental systems and stressor recurrence, might facilitate genetic assimilation of stress-induced effects. Accumulation of phenotypically neutral genetic variance by developmental systems and phenotypic accommodation of stress-induced effects, together with the inheritance of stress-induced modifications, ensure the evolutionary persistence of stress-response strategies and provide a link between individual adaptability and evolutionary adaptation.

Acclimatization↗

Congenic D1A dopamine receptor mutants: ethologically based resolution of behavioural topography indicates genetic background as a determinant of knockout phenotype.

D(1A)-null mice were backcrossed over 14 generations into a C57BL/6 background to result in essential elimination (to <0.005%) of any contribution from the 129/Sv component of their initially mixed (129/SvxC57BL/6) background. Their phenotype was assessed using an ethologically based approach that resolves each individual topography of behaviour in the natural repertoire. Habituation of sniffing, locomotion, rearing seated, and rearing to wall in wild types over several hours was profoundly retarded in congenic D(1A) mutants; conversely, rearing free and sifting were essentially abolished. Resultant increases in individual topographies of behaviour were substantially greater in congenic D(1A) mutants than in those on a mixed background. This phenotype was little altered by the selective D(1)-like antagonist SCH 23390 and could not be blocked by the selective D(2)-like antagonist YM 09151-2. The selective D(1)-like agonist SK&F 83959 could not further elevate those behaviours already heightened in congenic D(1A) mutants, while the induction of stereotyped sniffing and plodding locomotion by the selective D(2)-like agonist RU 24213 was disrupted. Genetic background appears to modulate critically the magnitude but not the general nature of the D(1A)-null phenotype, which may involve compensatory processes independent of other D(1)-like or D(2)-like receptors.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗

Studies on the genetics of feeding behaviour in the cave fish Astyanax mexicanus f. anoptichthys. An example of apparent monofactorial inheritance by polygenes.

The Mexican characid Astyanax mexicanus gave rise to a series of cavernicolous populations ("Anoptichthys") not earlier than during the Pleistocene age. When searching for food the blind cave fish swims at an angle of about 45 degrees to the ground. The river fish, however, when having no visual information, stands vertically on its head. With the aid of infrared-videorecording and on the basis of crossing experiments it could be demonstrated that this difference in feeding behaviour is controlled by polygenes, although frequency distributions of the crossings suggest an apparent monofactorial inheritance. The evolutionary processes of adaptive reduction of headstanding and of progressive development of the gustatory equipment are genetically independent and both traits have been achieved by small genetic steps.

Animals↗

Genetic, hormonal and behavioural influence on spontaneously developing arthritis in normal mice.

DBA/1 male mice develop arthritis spontaneously at the age of 4 months. The affected joints show cell-rich pannus formation without T cell infiltration and only limited MHC class II expression. Specific pathogen-free DBA/1 mice from different sources developed the same disease. Analyses of inbred mouse strains with various genetic backgrounds and F1 hybrids revealed that the disease is genetically dependent of DBA/1 recessive genes. However, F1 hybrids between DBA/1 and BXSB spontaneously developed arthritis with earlier onset than DBA/1 mice, suggesting that the BXSB autoimmune gene background had both permissive and contributing effects on the development of arthritis. The complete male preponderance for disease susceptibility was investigated by castration and testosterone treatment of DBA/1 males. No arthritis developed after castration and disease susceptibility was restored by testosterone treatment. Arthritis developed only where more than two males were kept in cages, suggesting an influence by aggressive behaviour. Thus, the spontaneous development of arthritis is dependent on hormonal and behavioural mediated effects and differs from experimental models for rheumatoid arthritis such as type II collagen-induced arthritis and pristane-induced arthritis. We conclude that the spontaneously developing arthritis in the normal DBA/1 strain may be more useful as a disease model for osteoarthritis than for rheumatoid arthritis.

Animals↗

Quantitative genetic analyses of complex behaviours in Drosophila.

Behaviours are exceptionally complex quantitative traits. Sensitivity to environmental variation and genetic background, the presence of sexual dimorphism, and the widespread functional pleiotropy that is inherent in behavioural phenotypes pose daunting challenges for unravelling their underlying genetics. Drosophila melanogaster provides an attractive system for elucidating the unifying principles of the genetic architectures that drive behaviours, as genetically identical individuals can be reared rapidly in controlled environments and extensive publicly accessible genetic resources are available. Recent advances in quantitative genetic and functional genomic approaches now enable the extensive characterization of complex genetic networks that mediate behaviours in this important model organism.

Animals↗

Resting behaviour, ecology and genetics of malaria vectors in large scale agricultural areas of Western Kenya.

In Kenya indoor and outdoor resting densities of Anopheles arabiensis and Anopheles funestus at the Ahero rice irrigation scheme, and Anopheles gambiae s.s., An. arabiensis and An. funestus at the Miwani sugar belt were assessed for 13 months by pyrethrum spray collections in houses and granaries. The vector's house leaving behaviour was evaluated with exit traps and it was noted that early exophily (i.e., deliberate) was not detected in any of the vectors. Assortative indoor/outdoor resting behaviour was studied by a capture-mark-release-recapture method and showed that in An. arabiensis both indoor and outdoor resting traits were present in the same individuals. Samples of half-gravid female An. gambiae s.l. were chromosomally identified either as Anopheles gambiae s.s. or An. arabiensis and in a subsample chromosomal inversions were read. Anopheles gambiae s.s. and An. arabiensis had the 2Rb inversion but in addition the 2La inversion was found in An. gambiae s.s. and this is an indication of low chromosomal variation. At Ahero An. arabiensis was most abundant when the rice crop was immature and An. funestus when the crop was mature. This succession of vectors facilitated the transmission of malaria throughout the year. At Miwani, An. gambiae s.l. population peaked during the long rains but the proportion of An. arabiensis was highest during the dry season. The indoor resting density of males of the three vector species was less than half of the females.

Agriculture↗

Do animal models have a place in the genetic analysis of quantitative human behavioural traits?

It seems that the genetic basis of common psychiatric diseases such as schizophrenia and manic-depressive psychosis is amenable to the genetic mapping strategies that have been successful in other complex disorders such as diabetes. The next challenge is the genetic dissection of quantitative behavioural traits such as mood, personality and intelligence. Quantitative traits pose new problems for gene cloning experiments. We argue that one way forward is by using animal models. One of the features of quantitative traits is that the DNA sequence variants which are responsible for them are unlikely to be immediately recognizable. In contrast to many qualitative traits where a discrete phenotypic difference is often the consequence of an inactivating mutation, the allelic variation responsible for quantitative traits probably has a more subtle basis. This distinction means that strategies to clone the genetic basis of quantitative behavioural traits will have to rely on functional assays of alleles thought to be important in determining the phenotype. We suggest that an efficient strategy for detecting sequences that give rise to quantitative behavioural traits can be devised in the mouse. The importance and utility of the mouse for quantitative trait analysis make it worthwhile to investigate mouse models of human behaviour; these advantages outweigh the difficulties that arise in attempts to validate the animal models. As an example we review the evidence that validates rodent emotionality as an animal model for susceptibility to human anxiety. We show that there is good evidence that rodent emotionality is a central nervous system state with a genetic basis, and that there are neuropharmacological and neuroanatomical parallels with human anxiety. Furthermore, our own work has shown that the genetic basis of the trait is relatively simple, and that the task of characterizing it at a molecular level is feasible. We expect that future experiments will show us how genetic variation gives rise to quantitative behavioural traits.

Animals↗

Regression and progression in neuroblastoma. Does genetics predict tumour behaviour?

Neuroblastoma (NB) is a heterogeneous disease. The clinical course may range from spontaneous regression and maturation to very aggressive behaviour. Stage 4s is a unique subcategory of NB, generally associated with good prognosis, despite skin and/or liver involvement and the frequent presence of tumour cells in the bone marrow. Another type of NB is the locally invasive tumour without bone and bone marrow involvement which can also have a good prognosis, irrespective of lymph node involvement. Unfortunately, there is only limited biological information on such tumours which have not been treated with cytotoxic therapy despite lymph node involvement, residual tumour mass after surgery and/or bone marrow infiltration. In order to find specific genetic changes common to NBs with a benign clinical course, we studied the genetic abnormalities of these tumours and compared them with highly aggressive tumours. We analysed a series of 54 localised and stage 4s tumours by means of in situ hybridisation performed on fresh cells or on paraffin embedded tissues. In addition, we performed classical cytogenetics, Southern blotting and PCR analysis on fresh tumour tissue. The majority of patients had been treated with surgery alone, and in a number of patients tumour resection was incomplete. Deletions at 1p36 and amplifications of the MYCN oncogene were absent, and diploidy or tetraploidy were not seen in any case, with residual localised tumours possessing a favourable outcome. Unexpectedly, one patient with a tetraploid 4s tumour without any genetic structural changes not receiving any cytotoxic treatment, did well. Interestingly, this genetic spectrum contrasted with that of progressing tumours, in which most had genetic aberrations, the deletion at 1p36 being the most common event. These data, although limited, suggest that an intact 1p36 (recognised by D1Z2), the absence of MYCN amplification and near-triploidy (at least in localised tumours), represent prerequisites for spontaneous regression and/or maturation.

Adolescent↗

Allochronic speciation, secondary contact, and reproductive character displacement in periodical cicadas (Hemiptera: Magicicada spp.): genetic, morphological, and behavioural evidence.

Periodical cicadas have proven useful in testing a variety of ecological and evolutionary hypotheses because of their unusual life history, extraordinary abundance, and wide geographical range. Periodical cicadas provide the best examples of synchronous periodicity and predator satiation in the animal kingdom, and are excellent illustrations of habitat partitioning (by the three morphologically distinct species groups), incipient species (the year classes or broods), and cryptic species (a newly discovered 13-year species, Magicicada neotredecim). They are particularly useful for exploring questions regarding speciation via temporal isolation, or allochronic speciation. Recently, data were presented that provided strong support for an instance of allochronic speciation by life-cycle switching. This speciation event resulted in the formation of a new 13-year species from a 17-year species and led to secondary contact between two formerly separated lineages, one represented by the new 13-year cicadas (and their 17-year ancestors), and the other represented by the pre-existing 13-year cicadas. Allozyme frequency data, mitochondrial DNA (mtDNA), and abdominal colour were shown to be correlated genetic markers supporting the life-cycle switching/allochronic speciation hypothesis. In addition, a striking pattern of reproductive character displacement in male call pitch and female pitch preference between the two 13-year species was discovered. In this paper we report a strong association between calling song pitch and mtDNA haplotype for 101 individuals from a single locality within the M. tredecim/M. neotredecim contact zone and a strong association between abdomen colour and mtDNA haplotype. We conclude by reviewing proposed mechanisms for allochronic speciation and reproductive character displacement.

Animals↗

Anxiety-related behaviour in C57BL/6 <--> BALB/c chimeric mice.

In a previous study on anxiety-related behaviours of the genetically and behaviourally distant inbred mouse strains C57BL/6 and BALB/c using the Elevated plus-maze (EPM) and Open-field (OF) apparatuses, we identified a number of variables, the factorial scores of which were grouped by principal component analysis (PCA) into factors specifically describing each inbred strain. We have now studied the effect of C57BL/6 and BALB/c haploid sets of genes on this behaviour by comparing EPM and OF variables of C57BL/6 and BALB/c versus C57BL/6 x BALB/c F1 hybrids (B6CBF1) and chimeric C57BL/6 x BALB/c (CHIM) mice. CHIM mice were made by embryo aggregation and the chimerism degree of their brain was inferred from coat black/white distribution. Discriminant analysis of EPM and OF factorial scores of C57BL/6, BALB/c and CHIM mice showed that CHIM mice with an exceeding (> or =80%) C57BL/6 or BALB/c coat component had behaviours similar to those of the predominant strain, whereas CHIM mice with intermediate chimerism differed from both inbred strains. Additional MANOVA analysis showed that the anxiety behaviour of CHIM mice with intermediate chimerism was similar to that of B6CBF1 mice as for factors not describing the inbred strains, including a motor activity mostly limited to protected areas, with attempts to approach the anxiogenic areas while processing/storing the external information. We conclude that the balanced presence of both C57BL/6 and BALB/c genetic backgrounds, either when carried by the same cell or by different cells, gives rise to a novel stress coping strategy described by factors different from those of the inbred strains.

Animals↗

Temperament and psychiatric disorder: the genetic contribution to behaviour in childhood.

The studies stemming from the New York longitudinal study of temperament in childhood are summarised and conceptual difficulties and problems arising from them are described. An alternative model of temperament provided by Buss and Plomin is also considered. Finally, a new typology of temperament is proposed. It is based on the suggestion that ordinary, non-pathological behaviours, in extreme form, can be viewed as manifestations of emotional disorder, hyperactivity and antisocial disorder. Empirical evidence derived both from twin studies and from epidemiological investigations is put forward to support this view.

Child↗

Behavioural effects of genetically engineered cells releasing dopa and dopamine after intracerebral grafting in a rat model of Parkinson's disease.

The relative importance of synaptic versus paracrine dopamine transmission for the occurrence of functional effects following intrastriatal grafting is not fully established. In the present study we grafted cell lines, expressing the form I of human tyrosine hydroxylase after infection with a recombinant retrovirus and selection in tyrosine-free-medium, to the denervated striatum in order to analyse the extent to which extracellular dopamine levels can be restored and the effect of a diffuse release of dopamine on motor impairement in a rat model of Parkinson's disease. In petri dish, the modified fibroblast cells (NIH.3T3) release DOPA constitutively whereas the modified endocrine cells (RIN) store and release dopamine in a regulated way. Interestingly, in denervated striatum, grafts of modified fibroblast cells produce DOPA which was efficiently converted into dopamine by the host striatal tissue. In the grafted striatum, both fibroblast and endocrine cells restore subnormal levels of diffuse release of dopamine which is notably unaffected and stimulated, respectively, by high concentration of potassium, in connection with the in vitro properties of the grafted cells. The intrastriatal grafts of modified cells partially reversed the apomorphine-induced but not the amphetamine-induced motor asymmetry. We discuss the implications of these results in the context of Parkinson disease.

Animals↗