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At least 613 records · Page 34Linked to original sources
PubMed1989

Arousal as an explanation for differences in rats selectively bred for differential alcohol sensitivity.

A common error made by behavior genetics researchers is breeding two lines for differences in central arousal rather than for a specific behavioral feature. Two lines of rats (Riley, Freed, & Lester, 1976) were selectively bred for locomotor impairment in response to a subhypnotic dose (1.5 g/kg) of ethanol. These lines (designated "most affected" and "least affected") were compared in a variety of tests and showed differences in a number of phenotypic traits in addition to locomotor impairment to ethanol. The published findings have been interpreted in light of a hypothesis suggesting adventitiously selected differences in central arousal between the two lines. This interpretation showed that their usefulness as animal models of alcoholism is seriously compromised.

Alcoholism↗
PubMed1999

Tryptophan hydroxylase gene polymorphism (A218C) and suicidal behaviors.

Serotonergic dysfunction is implicated in mood disorders and suicidal behaviors. Genetic variants of tryptophan hydroxylase (TPH), a rate-limiting enzyme in the biosynthesis of serotonin, were associated with suicidal behaviors in three reports, but were not found in other studies. We investigated the TPH A218C polymorphism in 151 subjects with mood disorders and 200 control subjects. The results demonstrated a significant difference in genotypic distribution between controls and depressed patients, but not bipolar patients. A positive association between TPH polymorphism and suicidal behaviors was found in depressed patients and not in bipolar patients. We suggest that the association of TPH variants and suicide might depend on the diagnosis, and TPH mutation plays no major role in the pathogenesis of bipolar disorders.

Adult↗
PubMed2003

Resolving multiple epigenetic pathways to adolescent depression.

BACKGROUND: Genotype x environment interaction (G x E) arises when genes influence sensitivity to the environment. G x E is easily recognized in experimental organisms that permit randomization of genotypes over fixed environmental treatments. Genotype-environment correlation (rGE) arises when genetic effects create or evoke exposure to environmental differences. Simultaneous analysis of G x E and such 'active' or 'evocative' rGE in humans is intractable with linear structural models widely used in behavioral genetics because environments are random effects often correlated with genotype. The causes of the environmental variation, therefore, need to be modeled at the same time as the primary outcome. METHODS: A Markov Chain Monte Carlo approach is used to resolve three distinct pathways involving genes and life events affecting the development of post-pubertal depression in female twins and its relationship to pre-pubertal anxiety: 1) the main of genes and environment; 2) the interaction of genes and environment (G x E); and 3) genotype-environment correlation (rGE). RESULTS: A model including G x E and rGE in addition to the main effects of genes and environment yields significant estimates of the parameters reflecting G x E and rGE. Omission of either G x E or rGE leads to overestimation of the effects of the measured environment and the unique random environment within families. CONCLUSIONS: 1) Genetic differences in anxiety create later genetic differences in depression; 2) genes that affect early anxiety increase sensitivity (G x E) to adverse life events; 3) genes that increase risk to early anxiety increase exposure to depressogenic environmental influences (rGE). Additional genetic effects, specific to depression, further increase sensitivity to adversity. Failure to take into account the effects of G x E and rGE will lead to misunderstanding how genes and environment affect complex behavior.

Adolescent↗
PubMed2000

Behavioral validation of the spontaneously hypertensive rat (SHR) as an animal model of attention-deficit/hyperactivity disorder (AD/HD).

A good model of a disorder is one that: (a) mimics, although in a simpler form than the full-blown clinical case, the fundamentals of the behavioral characteristics, in this case of people with Attention-Deficit/Hyperactivity Disorder (AD/HD;face validity); (b) conforms with a theoretical rationale for the disorder (construct validity); and (c) is able to predict aspects of behavior, genetics and neurobiology previously uncharted in the clinics (predictive validity). This article discusses the Spontaneously Hypertensive Rat (SHR) and some other putative animal models of AD/HD. It is argued that although other strains and species may be hyperactive and/or show attention deficits following genetic, environmental or pharmacological interventions, the SHR is presently the only strain shown to have the major behavioral symptoms of AD/HD. This does not mean that investigating other models cannot give valuable information.

Animals↗
PubMedDate not supplied

[Patterns of maternal behavior of rats genetically selected for opposite coping styles].

Maternal behavior of Koltushi High- and Low-avoidance (KHA and KLA) rats strains was assessed over the prewealing period (days 6-21). Ten litters of each strain were observed during the light phase of the light/dark cycle. In a series of experiments, rat pups were taken from the maternal nest and placed into the opposite corner of the cage. The following parameters of the maternal behavior were recorded: the latency of the first contact with the pups, pup licking, latency of carrying/retrieval of the first pup back to the nest, time of returning to the nest of the whole litter, and mother's spontaneous behavior (grooming and locomotion time) over the course of 10 min of observation. KLA mothers stayed with their pups and took care of them more frequently than KHA mothers during the light phase of the circadian cycle. Time of self-grooming was significantly higher in KHA rats. The highest levels of self-grooming of mothers was registered on the first day of testing. The latency of the first coming to pups after their removal from the nest was lower in KHA rats, but they needed more time to returned all pups to the nest. The experimental evidence suggests that the KHA but not KLA rats with the active coping style and higher stress reactivity display disorders in maternal behavior in a novel situation.

Adaptation, Psychological↗
PubMed1990

Effects of seizures on learning, memory, and behavior in the genetically epilepsy-prone rat.

To determine whether frequent seizures can cause deficits in learning and behavior, immature genetically epilepsy-prone rats (GEPRs) were subjected to 66 audiogenic stimulations (Group 1). GEPR littermates were handled and placed in the sound chamber but were not stimulated (Group 2). Group 3 comprised genetically epilepsy-resistant rats (GERRs) who received audiogenic stimulations but had no seizures. After 3 weeks of stimulations the rats were tested for learning, memory, and behavior using the T-maze, water maze, open field activity test, home cage intruder test, and handling test. When compared with the control GEPRs and GERRs, Group 1 rats reached criteria less frequently in the T-maze, required longer times to find the platform in the water maze, and were less active in the open field activity test, less aggressive in the home cage intruder test, and more irritable and aggressive in the handling test. This study demonstrates that frequent, brief seizures in immature animals result in significant detrimental changes in learning, memory, activity level, and behavior.

Acoustic Stimulation↗
PubMed2005

Dopaminergic modulation of arousal in Drosophila.

BACKGROUND: Arousal levels in the brain set thresholds for behavior, from simple to complex. The mechanistic underpinnings of the various phenomena comprising arousal, however, are still poorly understood. Drosophila behaviors have been studied that span different levels of arousal, from sleep to visual perception to psychostimulant responses. RESULTS: We have investigated neurobiological mechanisms of arousal in the Drosophila brain by a combined behavioral, genetic, pharmacological, and electrophysiological approach. Administration of methamphetamine (METH) suppresses sleep and promotes active wakefulness, whereas an inhibitor of dopamine synthesis promotes sleep. METH affects courtship behavior by increasing sexual arousal while decreasing successful sexual performance. Electrophysiological recordings from the medial protocerebrum of wild-type flies showed that METH ingestion has rapid and detrimental effects on a brain response associated with perception of visual stimuli. Recordings in genetically manipulated animals show that dopaminergic transmission is required for these responses and that visual-processing deficits caused by attenuated dopaminergic transmission can be rescued by METH. CONCLUSIONS: We show that changes in dopamine levels differentially affect arousal for behaviors of varying complexity. Complex behaviors, such as visual perception, degenerate when dopamine levels are either too high or too low, in accordance with the inverted-U hypothesis of dopamine action in the mammalian brain. Simpler behaviors, such as sleep and locomotion, show graded responses that follow changes in dopamine level.

Animals↗
PubMed1995

Alcohol, palatability, and taste reactivity.

The taste reactivity procedure provides a valuable tool for examining issues of palatability of alcohol solutions for rats. Given that alcohol is normally introduced to the internal milieu orally, taste factors must play an important role in the animal's decision to ingest or reject. Extensive studies of rats' reactivity to alcohol solutions have revealed several important variables that appear to affect palatability: solution concentration, alcohol experience, and postingestive consequences. In a recent selective breeding project, it has been found that taste reactivity to alcohol has a high heritability in rats. High ingestive responding and low ingestive responding rats were selected and bred to produce two lines. In the first selected generation, calculation of the realized heritability was 0.43; the cumulative realized heritability using the data from the second selected generation was 0.68. The introduction of the taste reactivity paradigm to the field of behavioral genetics may provide important information for the study of genetics, chemical senses, and alcohol consumption.

Animals↗
PubMed2002

Preschool social and cognitive behaviors: the Southern Illinois Twins.

The Southern Illinois Twins registry consists of a small group of twins from the southern Illinois area and some areas in Missouri and Kentucky, as well as siblings of twins and singletons who have been involved in the study. The current project has as its primary focus the identification of variables that predict aggressive and prosocial behaviors in preschoolers, especially to explore the etiology of individual differences in aggressive and prosocial behaviors from a behavior genetic perspective. Twins are tested yearly within months of their birthdays, from ages 1 year to 5 years. Siblings are tested at 5 years of age. At ages 1-4 years, children are tested on a cognitive battery and mother-child interactions are videotaped. At 5 years, children engage in a peer play situation in the lab. Results thus far suggest that aggression during play in the lab shows genetic influence, corroborating earlier parent rating studies.

Aggression↗
PubMed1978

[Early diagnosis of neoplasms].

Cancer is a generic term for a variant manifestation of life caused by genetic mutations of somatic cells. It is not only carcinogenesis which is basically a genetic phenomenon, but also tumor progression which can be influenced by various genetic factors. A group of tumors is known to be inherited in a Mendelian fashion. In addition a great number of single gene disorders is associated with the development of maligne tumors. The further study of these diseases will allow new insights into the fundamental mechanisms leading to clinical cancer. In this respect a series of immunodeficiency diseases is of particular interest. Several organ tumors which seem to occur more frequently in relatives of tumor patients are of practical importance. A more sophisticated classification of these tumors may illuminate their genetic behavior. The geneticist cannot only define groups of individuals with a high cancer risk, but he can identify genetic, e.g. chromosomal, aberrations of cancerous cells which enables him the early detection of neoplasia.

Chromosome Aberrations↗
PubMed1975

Modern trends in human genetics.

Every physician is deeply concerned with the tremendous advances in genetics during the last decade. Through 'gene surgery' DNA transplantation on both somatic and germinal tissue is feasible. Thus, genetic determinism is no longer ineluctable. Tissue culture is a tool to avoid cellular degeneration and achieve cellular immortality.Precise chromosome identification allows one to follow transmission from generation to generation, as well as human gene mapping. Through clinical and especially biochemical methods, genetic entities are dissected more accurately. Ecological genetics studies the risk inherent with drugs, radiations, chemicals and a myriad of environmental factors. On the other hand, behavioral genetics tend to specify the part of the genetic set in human behaviour. Computerized programmes are responsible for some significant advances in population genetics. Prenatal diagnosis, newborn screening programmes, heterozygote detection, and so on, and add a new dimension to genetic counseling. Knowing the part of inheritance in retinal affections, our speciality will greatly benefit from these recent advances in genetics.

Amniocentesis↗
PubMed2006

Genetic and environmental influences on age at sexual initiation in the Colorado Adoption Project.

Whereas the majority of research on adolescent sexual initiation has focused solely on environmental factors, the present study used behavioral genetic analyses to investigate the relative contributions of genetic and environmental influences. Structural equation models were fitted to data from adoptive and non-adoptive sibling pairs (231 biologically related pairs and 169 unrelated pairs) from the Colorado Adoption Project. Information from censored individuals who had not yet experienced sexual initiation was maximized by adapting the twin survival analysis method of Pickles et al. (Behav Genet 24(5):457-468, 1994) to accommodate adoptive and non-adoptive siblings. Point estimates of variance components from an ACE model, including additive genetic (A), shared environmental (C), and non-shared environmental (E) influences were 28%, 24%, and 48%, respectively. Despite the lower point estimate for shared environmental effects than additive genetic effects, a CE model provided the best fit to the data. However, because adoptive siblings provide a direct estimate of shared environmental influences there is greater power to detect shared environmental effects in adoption designs. Evidence for genetic influences from our data were somewhat lower than those obtained in previous twin studies, possibly reflecting a return to more socially conservative sexual attitudes, changing sexual behaviors, or ambiguities in the wording of questions commonly used in research on adolescent sexuality.

Adolescent↗