The key role of behaviour in animal camouflage

Animal camouflage represents one of the most important ways of preventing (or facilitating) predation. It attracted the attention of the earliest evolutionary biologists, and today remains a focus of investigation in areas ranging from evolutionary ecology, animal decision‐making, optimal strategies, visual psychology, computer science, to materials science. Most work focuses on the role of animal morphology per se, and its interactions with the background in affecting detection and recognition. However, the behaviour of organisms is likely to be crucial in affecting camouflage too, through background choice, body orientation and positioning; and strategies of camouflage that require movement. A wealth of potential mechanisms may affect such behaviours, from imprinting and self‐assessment to genetics, and operate at several levels (species, morph, and individual). Over many years there have been numerous studies investigating the role of behaviour in camouflage, but to date, no effort to synthesise these studies and ideas into a coherent framework. Here, we review key work on behaviour and camouflage, highlight the mechanisms involved and implications of behaviour, discuss the importance of this in a changing world, and offer suggestions for addressing the many important gaps in our understanding of this subject.     

The role of undernutrition in animal models of hyperactivity

The influence of neonatal growth retardation on subsequent spontaneous activity and activity following d-amphetamine (10 mg/kg, i.p.) was studied in CD-1 mice. Different growth rates were obtained by raising mice in litters of either 8 or 16 sucklings per lactating dam. The testing protocol was specifically designed to duplicate a procedure used to assess the influence of neonatal lead exposure on locomotor activity. At 35 to 37 days of age mice were individually tested for general locomotor activity and drug response. Developmental growth retardation influenced their pattern of habituation to the test apparatus and their locomotor response to emphetamine. It was concluded that growth retardation may partially account for behavioral effects previously attributed to the neurotoxic effects of viruses, 6-hydroxydopamine or inorganic lead.     

The importance of 'memory' in statistical models for animal feeding behaviour

We investigate models for animal feeding behaviour, with the aim of improving understanding of how animals organise their behaviour in the short term. We consider three classes of model: hidden Markov, latent Gaussian and semi-Markov. Each can predict the typical 'clustered' feeding behaviour that is generally observed, however they differ in the extent to which 'memory' of previous behaviour is allowed to affect future behaviour. The hidden Markov model has 'lack of memory', the current behavioural state being dependent on the previous state only. The latent Gaussian model assumes feeding/non-feeding periods to occur by the thresholding of an underlying continuous variable, thereby incorporating some 'short-term memory'. The semi-Markov model, by taking into account the duration of time spent in the previous state, can be said to incorporate 'longer-term memory'. We fit each of these models to a dataset of cow feeding behaviour. We find the semi-Markov model (longer-term memory) to have the best fit to the data and the hidden Markov model (lack of memory) the worst. We argue that in view of effects of satiety on short-term feeding behaviour of animal species in general, biologically suitable models should allow 'memory' to play a role. We conclude that our findings are equally relevant for the analysis of other types of short-term behaviour that are governed by satiety-like principles.     

Alcohol and genetics: new animal models.

In recent years, it has become increasingly evident that there is a genetic component to alcoholism. Attempts to isolate alcoholism genes have met with modest success, in part because alcoholism is a multigenic trait. Recently, experimental animal models and novel genetic manipulations have provided several clues as to the specific genes involved in alcoholism, and extensive research has identified many genes that might influence responses to alcohol. Although not all of these might be proven to influence drug sensitivity, research has provided evidence for the involvement of a few genes. Ultimately, findings from animal models that investigate the function of specific genes could aid the development of pharmacotherapies to treat alcohol dependence.     

The genetics of animal development

The stages of establishment of phenogenetics in the USSR are regarded in this paper. The major directions and schools in this field are described. Also, main achievements and conceptions developed by our phenogeneticists are analysed in detail.     

Iron homeostasis: insights from genetics and animal models

Disorders that perturb iron balance are among the most prevalent human diseases, but until recently iron transport remained poorly understood. Over the past five years, genetic studies of patients with inherited iron homeostasis disorders and the analysis of mutant mice, rats and zebrafish have helped to identify several important iron-transport proteins. With information being mined from the genomes of four species, the study of iron metabolism has benefited enormously from positional-cloning efforts. Complementing the genomic strategy, targeted mutagenesis in mice has produced new models of human iron diseases. The animal models described in this review offer valuable tools for investigating iron homeostasis in vivo.     

The role of GABAB mechanisms in animal models of absence seizures

Generalized absence seizures in humans are a unique type of epilepsy characterized by a synchronous, bilateral 3-Hz spike and wave discharge emanating from a cortical and thalamic network within the brain. The availability of a number of pharmacological and genetic animal models has provided us with the means with which to investigate the cellular and molecular mechanisms underlying these seizures. Over the last few years a significant amount of research in these models has focused on the role of the inhibitory GABA_B receptors, which have been previously described in a number of brain areas as being responsible for a long-lasting hyperpolarization and depression in neurotransmitter release. Initial studies provided evidence that the GABA_B receptor was capable of generating the low threshold calcium spike required for initiation of the burst firing, leading researchers to hypothesize that the GABA_B receptors, played a significant role in these seizures. Subsequent research took advantage of the new generation of GABA_B antagonists that became available in the early 1990s and demonstrated that in a number of models the seizures could be abolished by the administration of one of these compounds. Further biochemical, molecular, and electrophysiological experiments have been carried out to determine the exact involvement of GABA_B receptors and their mechanism of action. The current evidence and interpretations of this work are presented here.     

The role of breeding and genetics in animal production improvement in the developing countries

Availability of animal protein for human consumption is very low in the developing countries mainly because of low productivity of existing livestock; ways and means to improve productivity through breeding are discussed and some basic issues requiring further research pointed out.     

Continuous-time Markov chains as models for animal behaviour

A survey is given of the application of (functions of) continuous-time Markov chains in the statistical analysis of behavioural time series.     

遗传学史在遗传学教学中的作用

科学史的研究和发展状况能反映一个国家的科学技术水平,遗传学史是生命科学发展史的一个重要分支,21世纪是生命科学的世纪,在遗传学教学中加强遗传学发展史的介绍,不仅具有教育功能,使学生了解遗传学的产生和发展,而且可以培养学生的思维能力和科学素质。本文就遗传学史的教育功能及在教学中的作用进行论述。     

Human genetics, animal models and computer simulations for studying hypertension

Essential hypertension is probably caused by combinations of small quantitative changes in the expression of many genes together with environmental factors. In this article, strategies for studying hypertension using animal models are summarized with emphasis on the combined use of mouse models and computer simulations. We have chosen the rennin-angiotensin system as our main example. Future directions of hypertension research using gene targeting are also discussed.     

The mouse: genetics meets behaviour

Genetic studies in the mouse are important in the elucidation of molecular pathways that underlie behaviour. The advantages of the mouse for behavioural studies include an extensive array of genetic technologies and an elaborate behavioural repertoire that can be used to create models of human disease. This review discusses the relative advantages of forward and reverse genetic approaches to studying the genetic basis of behaviour in the mouse, and the complexities that behavioural studies need to address, such as phenotypic variability, genetic background effects and pleiotropy.     

An everlasting role of animal models in understanding human disease

<正>Model organisms have been widely used to dissect important biological phenomena, as well as to explore potential causes and treatments for human disorders. Much of our knowledge on molecular mechanisms underlying the heredity, development as well as physiology is largely derived from the researches of model organisms. We have witnessed     

The role of chemokines in atherosclerosis: recent evidence from experimental models and population genetics

PURPOSE OF REVIEW: Atherosclerosis is an inflammatory disease process. This review discusses the recent genetic evidence from animal models and human populations that highlight the importance of chemokines in atherosclerosis. RECENT FINDINGS: CC-chemokine/CC-chemokine receptors (CCR), including CCR2/ MCP-1 (monocyte chemoattractant protein-1) and CCR5/RANTES (regulated on activation, normal T-cell expressed and secreted), have been shown in animal knockout and transgenic studies to have significant effects on atherosclerotic lesion size and macrophage recruitment. More recently fractalkine (CX3C1) and its receptor (CX3CR1) have emerged as another important pathway in atherosclerosis. For example, fractalkine is present in human atherosclerotic lesions and is able to stimulate platelet activation and adhesion. CX3CR1 is expressed on human aortic smooth muscle cells and CX3CR1/apolipoprotein E double knockout mice have significantly reduced atherosclerotic lesion size and macrophage recruitment. Human population genetic studies have tried to assess the importance of chemokines in human atherosclerosis. Currently, there is conflicting evidence regarding an association between polymorphisms in CCR2/MCP-1 and CCR5/RANTES and coronary artery disease. There is evidence, however, for an association between the fractalkine receptor polymorphism (CX3CR1-I249) and coronary artery disease in both human population and function studies. SUMMARY: Recent transgenic and gene knockout studies in murine models of atherosclerosis have highlighted the importance of chemokines and their receptors in atherosclerosis. Genetic evidence for a role of chemokines and their receptors in human population studies remains under investigation. Identifying chemokine polymorphisms could help to determine pathways that are important in atherosclerosis disease pathology and that may suggest novel therapeutic targets.