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At least 343 records · Page 19Linked to original sources
PubMed2006

Social structures in Pan paniscus: testing the female bonding hypothesis.

Based on previous research in captivity, bonobos, Pan paniscus, have been called a female-bonded species. However, genetic and behavioural data indicate that wild females migrate. Bonding between these unrelated females would then be in contradiction with socio-ecological models. It has been argued that female bonding has been overemphasized in captive bonobos. We examine patterns of proximity, grooming and support behaviour in six well established captive groups of bonobos. We find that female bonding was not a typical characteristic of all captive bonobo groups. In only two groups there was a trend for females to prefer proximity with other females over association with males. We found no evidence that following or grooming between females was more frequent than between males and unrelated females or between males. Only in coalitions, females supported each other more than male-female or male-male dyads. We also investigated five mother-son pairs. Grooming was more frequent among mothers and sons than in any other dyad, but sons did not groom their mothers more than males groomed unrelated females. Mothers groomed their sons, or provided more support to them than females groomed or supported unrelated males. Thus, while bonds between females were clearly present, intersexual relations between males and either unrelated females or their mothers are of more, or equal importance.

Animals↗
PubMed1996

Differences in benzodiazepine binding in quail selectively bred for differences in tonic immobility.

We have previously found that quail selectively bred to exhibit long (LTI) or short (STI) tonic immobility responses to manual restraint differed with respect to the affinity of binding at the diazepam-sensitive benzodiazepine binding site. In the current study, binding at other components of the GABAA-benzodiazepine receptor complex was investigated. Whereas the lines did not differ in either number or affinity of GABAA receptors, we found that GABA caused significantly greater enhancement of [3H]flunitrazepam binding in the forebrains of LTI than in STI birds. There was also significantly higher binding to the diazepam-insensitive component (alcohol binding site) of the GABAA-benzodiazepine complex in the forebrain of the LTI line. It is not known, however, whether this difference in the lines is due to differences in number or affinity of these sites. It is discussed whether these manifold differences between the lines in binding at the forebrain sites of the GABAA-benzodiazepine complex could be founded on subunit differences, and whether differences in benzodiazepine binding could underlie the genetically determined behavioural differences in tonic immobility.

Animals↗
PubMed2000

Effects of environmental change on emerging parasitic diseases.

Ecological disturbances exert an influence on the emergence and proliferation of malaria and zoonotic parasitic diseases, including, Leishmaniasis, cryptosporidiosis, giardiasis, trypanosomiasis, schistosomiasis, filariasis, onchocerciasis, and loiasis. Each environmental change, whether occurring as a natural phenomenon or through human intervention, changes the ecological balance and context within which disease hosts or vectors and parasites breed, develop, and transmit disease. Each species occupies a particular ecological niche and vector species sub-populations are distinct behaviourally and genetically as they adapt to man-made environments. Most zoonotic parasites display three distinct life cycles: sylvatic, zoonotic, and anthroponotic. In adapting to changed environmental conditions, including reduced non-human population and increased human population, some vectors display conversion from a primarily zoophyllic to primarily anthrophyllic orientation. Deforestation and ensuing changes in landuse, human settlement, commercial development, road construction, water control systems (dams, canals, irrigation systems, reservoirs), and climate, singly, and in combination have been accompanied by global increases in morbidity and mortality from emergent parasitic disease. The replacement of forests with crop farming, ranching, and raising small animals can create supportive habitats for parasites and their host vectors. When the land use of deforested areas changes, the pattern of human settlement is altered and habitat fragmentation may provide opportunities for exchange and transmission of parasites to the heretofore uninfected humans. Construction of water control projects can lead to shifts in such vector populations as snails and mosquitoes and their parasites. Construction of roads in previously inaccessible forested areas can lead to erosion, and stagnant ponds by blocking the flow of streams when the water rises during the rainy season. The combined effects of environmentally detrimental changes in local land use and alterations in global climate disrupt the natural ecosystem and can increase the risk of transmission of parasitic diseases to the human population.

Animals↗
PubMed1999

Co-adaptation of pheromone production and behavioural responses in Drosophila melanogaster males.

In Drosophila melanogaster, male courtship behaviour is genetically controlled and is influenced by sex pheromones. 7-tricosene (7-T) induces a dose-dependent inhibition of male-male courtship, whereas 7,11-dienes stimulate male courtship of females. There is a geographical quantitative variation in the production of two predominant male hydrocarbons, 7-T and 7-pentacosene (7-P). We have previously found that 7-P, the main hydrocarbon from males of West African strains, stimulates males that mainly produce 7-T. Using both 'natural' and genetically engineered strains, we find that genetic factors coding for low levels of 7-P in males have co-evolved with factor(s) coding for male responses to high levels of 7-P. These two phenotypes are coded by factors on different chromosomes: the intraspecific polymorphism for the production of 7-T and 7-P is largely controlled by chromosome 2, whereas the variation in courtship towards 7-P-rich males is largely controlled by chromosome 3. The polymorphism of male courtship towards 7-P-rich males shows no correlation with the variation in male responses to female flies.

Alkenes↗
PubMed2002

A twin study of genetic and environmental influences on suicidality in men.

BACKGROUND: Previous studies that have examined genetic influences on suicidal behaviour were confounded by genetic vulnerability for psychiatric risk factors. The present study examines genetic influences on suicidality (i.e. suicidal ideation and/or suicide attempt) after controlling for the inheritance of psychiatric disorders. METHODS: Sociodemographics, combat exposure, lifetime DSM-III-R major depression, bipolar disorder, childhood conduct disorder, adult antisocial personality disorder, panic disorder, post-traumatic stress disorder, drug dependence, alcohol dependence and lifetime suicidal ideation and attempt were assessed in 3372 twin pairs from the Vietnam Era Twin Registry who were assessed in 1987 and 1992. Genetic risk factors for suicidality were examined in a multinomial logistic regression model. Additive genetic, shared environmental and non-shared environmental effects on suicidality were estimated using structural equation modelling, controlling for other risk factors. RESULTS: The prevalence of suicidal ideation and suicide attempt were 16.1% and 2.4% respectively. In a multinomial regression model, co-twin's suicidality, being white, unemployment, being other than married, medium combat exposure and psychiatric disorders were significant predictors for suicidal ideation. Co-twin's suicidality, unemployment, marital disruption, low education attainment and psychiatric disorders (except childhood conduct disorder) were significant predictors for suicide attempt. Model-fitting suggested that suicidal ideation was influenced by additive genetic (36%) and non-shared environmental (64%) effects, while suicide attempt was affected by additive genetic (17%), shared environmental (19%) and non-shared environmental (64%) effects. CONCLUSIONS: There may be a genetic susceptibility specific to both suicidal ideation and suicide attempt in men, which is not explained by the inheritance of common psychiatric disorders.

Adult↗
PubMed2000

Impulsiveness, serotonin genes and repetition of deliberate self-harm (DSH).

BACKGROUND: Few studies have investigated independent associations of psychological, biological and social variables with repeated deliberate self-harm (DSH). Serotonin function has been linked to impulsive and suicidal behaviour and genetic polymorphisms have been identified within the serotonin system that could account for this link. This study tested hypotheses linking impulsiveness, genetic polymorphisms of tryptophan hydroxylase (TPH) and the 5-HT2c receptor and repeated DSH. METHODS: Individuals presenting after DSH were interviewed, completed personality questionnaires and gave venous blood samples. Genotypes were determined for TPH intron7 and 5-HT2c (cys-ser) polymorphisms. Follow-up to identify repetition of DSH was for 1 year. RESULTS: Males with the 5-HT2c serine variant were more impulsive than those with the cysteine variant (039 standardized units, P = 0.041, 95% CI 0.017 to 0.076). There was no association between impulsiveness and the TPH intron7 polymorphism overall but a weak association with the L allele in men (0.41 standardized units, P = 0.05, 95 % CI 0.001 to 0.82). Impulsiveness, although high in the group as a whole, did not distinguish those who repeated DSH. CONCLUSIONS: The personality trait of impulsiveness may in part be related to genotypes of the 5-HT2c receptor and TPH gene in men. Impulsiveness does not differ between those who do and do not repeat DSH.

Adult↗
PubMed2006

[Metabolic syndrome and depression].

The metabolic syndrome is defined as a constellation of metabolic abnormalities, including glucose intolerance, obesity, dyslipidaemia, and hypertension. It is associated with an elevated risk for cardiovascular disease and type 2 diabetes. Over the past 20 years, a worldwide increase of the metabolic syndrome has taken place. In the USA, 21% to 39% of the general population suffer from metabolic syndrome; in Europe prevalence rates are lower. At the same time, depressive disorders, which are associated with a 1.5 to 2.5 fold risk for cardiovascular events, are increasing. The combination of metabolic syndrome and depression multiplies the risk for severe complications: Due to behavioural, physiological, genetic, and treatment-induced factors, depression stimulates the development of a metabolic syndrome. In reverse, the metabolic syndrome favours development and maintenance of the metabolic syndrome. Consequently, in patients suffering from metabolic syndrome and depression, both disorders must be treated simultaneously. The treatment plan includes weight reduction, physical activity, psychoeducation, family interventions, the patient's subjective explanatory and treatment models, cognitive techniques, and problem solving techniques. Weight, blood pressure, fastening glucose, haemoglobin A1c, and lipids must be controlled in order to monitor treatment progress. Additional drug treatment can be appropriate for hypertension, dyslipidaemia, hyperglycaemia, and depression. Under these conditions, sustained improvements of individual well-being, psychosocial risk-factors, functional limitations, glycemic control, hypertension, and obesity are possible.

Comorbidity↗
PubMed2003

The influence of genetic factors on physical functioning and exercise in second half of life.

During the past decades, a number of studies of families and twins in particular have assessed the relative contribution of genetic and environmental factors to traits reflecting various aspects of physical functioning: maximal O2 uptake, muscular endurance, muscular strength, muscle cross sectional area, flexibility, and trainability. Although the estimate of the size of the genetic component differs between the various studies, they point towards a moderate to substantial genetic influence on these phenotypes. Most of the studies have used only young and healthy study subjects, although in recent years phenotypes of particular importance to the elderly and the oldest-old (e.g., activities-of-daily living abilities) have also been shown to have substantial genetic component. Furthermore, behavioural studies have also revealed a genetic contribution to the disposition to level of leisure time physical activity. At present, there is still a few association studies on specific genetic variants, and the results have either been inconsistent or failed to show an association with physical functioning. Therefore, the mechanisms through which the genetic influence is expressed, is still an enigma. Here, we summarise the evidence currently available for a genetic influence on physical functioning and disposition to leisure time physical activity with a focus on recent Danish twin data.

Aging↗
PubMed2006

A C. elegans stretch receptor neuron revealed by a mechanosensitive TRP channel homologue.

The nematode Caenorhabditis elegans is commonly used as a genetic model organism for dissecting integration of the sensory and motor systems. Despite extensive genetic and behavioural analyses that have led to the identification of many genes and neural circuits involved in regulating C. elegans locomotion behaviour, it remains unclear whether and how somatosensory feedback modulates motor output during locomotion. In particular, no stretch receptors have been identified in C. elegans, raising the issue of whether stretch-receptor-mediated proprioception is used by C. elegans to regulate its locomotion behaviour. Here we have characterized TRP-4, the C. elegans homologue of the mechanosensitive TRPN channel. We show that trp-4 mutant worms bend their body abnormally, exhibiting a body posture distinct from that of wild-type worms during locomotion, suggesting that TRP-4 is involved in stretch-receptor-mediated proprioception. We show that TRP-4 acts in a single neuron, DVA, to mediate its function in proprioception, and that the activity of DVA can be stimulated by body stretch. DVA both positively and negatively modulates locomotion, providing a unique mechanism whereby a single neuron can fine-tune motor activity. Thus, DVA represents a stretch receptor neuron that regulates sensory-motor integration during C. elegans locomotion.

Animals↗
PubMed2006

Insights into social insects from the genome of the honeybee Apis mellifera.

Here we report the genome sequence of the honeybee Apis mellifera, a key model for social behaviour and essential to global ecology through pollination. Compared with other sequenced insect genomes, the A. mellifera genome has high A+T and CpG contents, lacks major transposon families, evolves more slowly, and is more similar to vertebrates for circadian rhythm, RNA interference and DNA methylation genes, among others. Furthermore, A. mellifera has fewer genes for innate immunity, detoxification enzymes, cuticle-forming proteins and gustatory receptors, more genes for odorant receptors, and novel genes for nectar and pollen utilization, consistent with its ecology and social organization. Compared to Drosophila, genes in early developmental pathways differ in Apis, whereas similarities exist for functions that differ markedly, such as sex determination, brain function and behaviour. Population genetics suggests a novel African origin for the species A. mellifera and insights into whether Africanized bees spread throughout the New World via hybridization or displacement.

Animals↗
PubMed2001

Auditory and vestibular defects in the circling (ci2) rat mutant.

The circling rat is an autosomal recessive mutant (homozygous ci2/ci2) that displays lateralized circling behaviour, locomotor hyperactivity, ataxia and stereotypic head-movement. These abnormal behaviours occur in phases or bursts either spontaneously or in response to stress. Heterozygous (ci2/+) littermates display normal spontaneous behaviours. We have previously found that ci2/ci2 rats of both genders have a lower tissue content of dopamine in the striatum ipsilateral to the preferred direction of rotation, indicating that the rats turn away from the brain hemisphere with higher striatal dopaminergic activity. In view of the similarities of the motor syndrome of the ci2/ci2 mutant rat to that of mouse deafness mutants, the present study evaluated the hearing ability of the circling rat mutant by recording brainstem auditory-evoked potentials. To test for vestibular dysfunction, a swimming test was conducted. Histological methods were used to examine the cochlear and vestibular parts of the inner ear and the cochlear and vestibular brainstem nuclei for defects. The absence of auditory-evoked potentials demonstrated a complete hearing loss in the adult ci2/ci2 mutant rat, whereas heterozygous littermates exhibited auditory-evoked potentials with thresholds resembling those of other laboratory strains. Furthermore, the mutant rats were unable to swim. Histological analysis of the inner ear of adult mutants revealed virtually complete loss of the cochlear neuroepithelium, while no such hair cell degeneration was seen in the vestibular parts of the inner ear. However, part of the vestibular hair cells showed protrusions into the endolymphatic space, suggesting alterations in the cytoskeletal architecture. The histological findings in mutant circling rats strongly indicate that the hearing loss of the mutants is of the sensory neural type, the most prevalent type of hearing loss. In the cochlear nuclei of the brain stem of mutant rats, neurons exhibited an abnormal shape, reduced size and increased density compared to controls. In contrast, no abnormal neuronal morphology was seen in the vestibular nuclei, but a significantly reduced neuronal density was found in the medial vestibular nucleus. Abnormal vestibular function would be a likely explanation for the disturbed balance of mutant rats as exemplified by the ataxia and the inability to swim, whereas the previous data on these rats strongly indicate an involvement of the basal ganglia in the abnormal circling behaviour. The genetic defect in the mutant rats, thus, results in a clinical syndrome with features also seen in human genetic disorders with deafness and hyperkinesia, making the ci2/ci2 rat an excellent model for investigating both cochlear/vestibular dysfunction and hyperkinetic movement disorders.

Animals↗
PubMed1997

Prospective study of bone loss in pre- and post-menopausal women on L-thyroxine therapy for non-toxic goitre.

OBJECTIVE: Hyperthyroidism is associated with increased bone turnover and bone resorption, but the effects of suppressive doses of thyroxine in treating non-toxic goitre remain unclear. We carried out a longitudinal study to evaluate the effect on bone of L-thyroxine (L-T4) therapy in women with non-toxic goitre. SUBJECTS: Forty Caucasian women, 19 of whom were pre-menopausal and 21 post-menopausal, were studied before and after 12 months' L-T4 therapy for non-toxic goitre; 40 women matched for age, body mass index and menopausal status were used as controls. DESIGN: The minimal dosage of L-T4 (mean +/- standard error = 1.5 +/- 0.1 micrograms/kg-1 day-1) was given to each patient to obtain subnormal but detectable serum TSH (< or = 0.2 mU/l). Patients and controls were assessed for minor determinants of bone loss rate, such as genetic and behavioural factors. MEASUREMENTS: Bone mineral density (BMD) of the lumbar spine, femoral neck, trochanter and Ward's triangle was measured by dual-energy X-ray absorptiometry at baseline and 12 months; serum and urine markers of bone turnover was measured at baseline, 3, 6 and 12 months. RESULTS: No significant difference was detected in BMD values between patients and controls either at presentation or at the 12-month follow-up. Pre-menopausal patients showed a significant decrease in femoral neck BMD (-1.7 +/- 0.6%, P < 0.05) while controls showed no change +0.2 +/- 0.9%, P = NS). Post-menopausal patients showed a significant decrease in BMD of the lumbar spine (-1.3 +/- 0.6%, P < 0.05; controls +0.0 +/- 0.4%, P = NS), femoral neck (-1.5 +/- 0.6%, P < 0.05; controls -1.2 +/- 0.8%, P = NS) and trochanter (-2.1 +/- 0.8%, P < 0.05; controls -1.4 +/- 0.9%, P = NS). In both pre- and post-menopausal patients the serum markers of bone turnover, alkaline phosphatase and osteocalcin, showed an early and progressive increase. A linear relationship was found only between the 3-month values of serum osteocalcin and the urine hydroxyproline/creatinine ratio in both pre-menopausal (r = 0.87, P < 0.01) and post-menopausal (r = 0.72, P < 0.05) patients. No correlation was found between bone loss or changes in bone turnover markers and L-T4 dose or thyroid hormone levels. CONCLUSIONS: This longitudinal study suggests that TSH-suppressive therapy with L-thyroxine for non-toxic goitre significantly increases the bone mineral turnover and might contribute to a BMD reduction, more marked on cortical bone, in both pre- and post-menopausal women.

Absorptiometry, Photon↗
PubMed1998

Intraspecific variation in sperm size characters.

Interspecific variation in quantitative characters of sperm is considerable and can sometimes be related to aspects of sperm competition. In contrast, continuous intraspecific variation is often ignored; for example, many studies concentrate on measuring a species-typical sperm size. However, statistically significant variation amongst males in a variety of sperm size characters, particularly total length and a number of head characters, has been reported in at least 13 species. Furthermore, sperm size has been shown to influence the outcomes of processes involved in sperm competition in two species, with larger sperm being more successful in both cases. It is suggested here that intraspecific variation may be a widespread phenomena, further examination of which could contribute considerably to our understanding of sperm evolution. Size differences between the sperm of competing males could be used in controlled matings to investigate the fates of sperm within female tracts and storage organs, but care should be taken that size characters may not be neutral markers. Furthermore, the genetic determination of sperm size is considerable (h2 = 0.56-0.92 for total length and a number of head characters) and determinants are at least sometimes sex-linked, with the result that particular care must go into experimental design if genetic effects are to be fully elucidated. Studies combining genetical and behavioural effects of intraspecific variation in sperm morphology should be particularly rewarding.

Animals↗
PubMed1998

Isolation of seven unique biogenic amine receptor clones from the honey bee by library scanning.

The biogenic amine receptor genes constitute an ancient and highly divergent family within the larger superfamily of G-protein-coupled receptors. These receptors play a central role in modulating nerve cell activity and thus behaviour. Because the honey bee offers numerous advantages for behavioural studies we endeavoured to isolate as many members of this gene family as possible from the bee. We compared numerous approaches to gene isolation and found that PCR amplification from small subfractions of cDNA or genomic DNA libraries enabled us to isolate clones that are otherwise undetectable. In total we isolated seven biogenic amine receptor clones and identified five additional related sequences by low-stringency Southern hybridization. Two clones, AmBAR4 and AmBAR6, are 84% and 72% identical to the Drosophila 5-HT2 and D1b receptors, respectively, and probably represent orthologous genes. Phylogenetic analysis indicates that AmBAR5 clusters loosely with a variety of tyramine and octopamine receptors with which it shares <66% identity. The other four clones, AmBAR1, AmBAR2, AmBAR3 and AmBAR7, are weakly to moderately related (28-45% identical) to Drosophila dopaminergic or mammalian adrenergic receptors and probably represent receptors of these classes whose orthologues have not previously been isolated from any insect. The honey bee clones expand the size of the known insect biogenic amine receptor gene family to sixteen members. Therefore the size of the biogenic amine receptor gene family of insects approaches that of vertebrates. This is true despite the reduced behavioural and genetic complexity of the insects relative to vertebrate animals.

Amino Acid Sequence↗
PubMed1999

A phylogeographical analysis of the bemisia tabaci species complex based on mitochondrial DNA markers

Mitochondrial 16S ( approximately 550 bp) and cytochrome oxidase I (COI) ( approximately 700 bp) sequences were utilized as markers to reconstruct a phylogeography for representative populations or biotypes of Bemisia tabaci. 16S sequences exhibited less divergence than COI sequences. Of the 429 characters examined for COI sequences, 185 sites were invariant, 244 were variable and 108 were informative. COI sequence identities yielded distances ranging from less than 1% to greater than 17%. Whitefly 16S sequences of 456 characters were analysed which consisted of 298 invariant sites, 158 variable sites and 53 informative sites. Phylogenetic analyses conducted by maximum parsimony, maximum-likelihood and neighbour-joining methods yielded almost identical phylogenetic reconstructions of trees that separated whiteflies based on geographical origin. The 16S and COI sequence data indicate that the B-biotype originated in the Old World (Europe, Asia and Africa) and is most closely related to B-like variants from Israel and Yemen, with the next closest relative being a biotype from Sudan. These data confirm the biochemical, genetic and behavioural polymorphisms described previously for B. tabaci. The consideration of all global variants of B. tabaci as a highly cryptic group of sibling species is argued.

Journal Article↗
PubMed2001

Tactic-specific success in sperm competition.

Sperm competition is a major force in sexual selection, but its implications for mating-system and life-history evolution are only beginning to be understood. The well-known sneak-guard model predicts that sneaks will win in sperm competition. We now provide empirical confirmation of this prediction. Bluegill sunfish (Lepomis macrochirus) have both sneak (cuckolder) and guard (parental) males. Guards make nests, court females and provide solitary parental care for the embryos. Sneaks include small cuckolders, which are termed 'sneakers', that dart in and out of nests in order to ejaculate between the spawning pair and larger cuckolders, which are termed 'satellites', that mimic females in order to ejaculate between the spawning pair. Using field behavioural data, genetic data and new mathematical models for paternity analyses, we show, for the first time to the authors' knowledge, that sneaks fertilize more eggs than guards during sperm competition. In addition, we show that sneakers are superior to satellites in sperm competition and, thus, that even among sneaks there are tactic-specific differences in competitive success.

Animals↗
PubMed2001

Alliance membership and kinship in wild male bottlenose dolphins (Tursiops aduncus) of southeastern Australia.

Bottlenose dolphins are one of only a few mammalian taxa where the males are known to cooperate within their social group in order to maintain mating access to single females against other males. Male bonds in bottlenose dolphins have been hypothesized as evolving through kinship and associated inclusive fitness effects. In this study we tested whether individually identified male bottlenose dolphins preferentially associate and form alliances with kin in a small coastal resident population of southeastern Australia using a combination of behavioural data, genetic sexing, sequences of the mitochondrial DNA control region and nuclear microsatellite markers. Males generally associated significantly more often than expected with one to three other males, with whom they jointly herded females for mating. Associations and alliance membership were not associated with either maternal kinship or genetic relatedness. The majority of male pairs within alliances were randomly related, although high relatedness values were found between males of different alliances in the resident population. These findings indicate that mechanisms other than kin selection may be foremost in the development and maintenance of cooperation between male bottlenose dolphins.

Animals↗
PubMed2004

Molecular evidence of post-copulatory inbreeding avoidance in the field cricket Gryllus bimaculatus.

Female promiscuity has broad implications for individual behaviour, population genetics and even speciation. In the field cricket Gryllus bimaculatus, females will mate with almost any male presented to them, despite receiving no recorded direct benefits. Previous studies have shown that female crickets can benefit from polyandry through increased hatching success of their eggs. There is evidence that this effect is driven by the potential of polyandrous females to avoid fertilizing eggs with sperm from genetically incompatible males. We provide direct evidence supporting the hypothesis that polyandry is a mechanism to avoid genetic incompatibilities resulting from inbreeding. Using microsatellite markers we examined patterns of paternity in an experiment where each female mated with both a related and an unrelated male in either order. Overall, unrelated males were more successful in gaining paternity than were related males, but this effect was driven by a much greater success of unrelated males when they were the first to mate.

Animals↗