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Results for “Evolutionary adaptability”

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PubMed1998

The evolved basis and adaptive functions of cognitive distortions.

This paper explores common cognitive distortions from the perspective of evolutionary psychology. It is suggested that cognitive distortions are natural consequences of using fast track defensive algorithms that are sensitive to threat. In various contexts, especially those of threat, humans evolved to think adaptively rather than logically. Hence cognitive distortions are not strictly errors in brain functioning and it can be useful to inform patients that 'negative thinking' may be dysfunctional but is a reflection of basic brain design and not personal irrationality. The evolved nature of cognitive distortions has been implicit in cognitive therapy from its early days (Beck, 1963; Ellis, 1962) but has not been fully articulated in what is now known about evolved mental processes. Many forms of cognitive distortion can be seen to use the (previously) adaptive heuristic of better safe than sorry.

Adaptation, Psychological↗

PubMed1999

Brief communication: Resistance to Falciparum malaria in alpha-thalassemia, oxidative stress, and hemoglobin oxidation.

A recent survey conducted on Vanuatu Island suggests that resistance to Plasmodium falciparum in alpha-thalassemic individuals may have an immunological basis. This study is important since it seems to undermine the current idea that red-cell genetic defects give protection against falciparum malaria by reducing intraerythrocytic growth and development of the parasite. However, the mechanisms underlying these clinical and genetic observations are not yet fully understood. Based on a review of the relevant literature, we first show that the model based on the interaction between hemoglobin (Hb) and membrane components may provide a molecular basis for the involvement of the immune response in genetic adaptation to malaria. Second, we discuss the main evolutionary implications of the model. Finally, we suggest two approaches by which anthropological studies could provide a useful way of testing the model: 1) analysis of the interactions of malaria-resistance genes with genetic polymorphisms which affect the erythrocyte redox status and 2) study of the antimalarial effects of natural products (introduced as a part of a diet or for traditional antimalarial therapy) capable of interfering with the Hb/membrane interaction.

Animals↗

PubMed1998

Evolution of the immune repertoire with and without somatic DNA recombination.

Repertoire of an immune system is a set of antigen receptors each having a unique specificity to bind an antigen. In many vertebrate species, antigen receptors are produced via combinatorial arrangements of DNA segments in specialized immune cells. Due to this molecular mechanism, repertoire of vertebrate species is potentially very large. The diversity of repertoire is thought to guarantee recognition of most ill-causing micro-organisms. In vertebrate species however, similar editing of DNA segments has not been demonstrated to take place. Immune system of invertebrate species therefore seems to operate in a distinct manner from that of vertebrate species. Using an evolutionary model in which organisms struggle to fight infections, we attempt to understand why some species use a more diverse set of antigen receptors than others. Individuals in our model either use somatic DNA recombination to produce antigen receptors (as in vertebrates) or do not use such a mechanism (as in vertebrates). We found that individuals having an invertebrate-like immune system came to employ only a few antigen receptors to recognize a set of pathogens whereas those with a vertebrate-like immune system use a larger set of more specific antigen receptors to recognize the same set of pathogens. Our interpretation of this finding is that because the genetics of the immune system imposed different constraints on the evolutionary process, two distinct recognition strategies have been adapted by these species.

Animals↗

PubMed1995

Alzheimer's disease: maladaptive synaptoplasticity hypothesis.

A deposition of amyloid is considered by many to be the principal causative event in Alzheimer's disease, with abnormal neurites, neurofibrillary tangles, cell loss, and dementia all occurring secondarily to this. This present hypothesis differs by proposing a maladaptive synaptoplastic response, in conjunction with an involution of cortico-cortical projection neurons, as the principal causative events. The specificity of the maladaptive synaptoplastic response for a subpopulation of human nerve cells is related to the evolutionary advancement of the association cortex and the adaptation of functionally connected brain regions.

Adaptation, Physiological↗

PubMed1983

Histochemical and morphological muscle-fibre characteristics of the human masseter, the medial pterygoid and the temporal muscles.

An extensive histochemical and quantitative analysis of various portions of the human masseter, the medial pterygoid and the temporal muscles was performed in young adult males with normal intermaxillary relationships and complete dentition. There was marked and locally radical intramuscular variability in the muscle-fibre composition. Each muscle and the subunits of the muscles exhibited a characteristic fibre pattern--both the relative frequency and the diameter of the various fibre types differed significantly between the different portions. The fibre pattern was quantitatively different to that of the human lateral pterygoid muscle and both quantitatively and qualitatively dissimilar to that of the human digastric muscle and that of normal limb and trunk muscles. A large proportion of the fibres were ATPase intermediate fibres and must be regarded as being a part of the normal fibre population of the human mandibular elevator muscles. Type IIA fibres were rare. As muscle-fibre differentiation is considered to be influenced by motoneurone function, it can be assumed that the complex fibre pattern of the jaw-closing muscles is related to the unique function of the human mandibular locomotor system. A functional specialization is suggested providing optimal jaw control. Compared with the lateral pterygoid muscle (with predominantly type I fibres) and the digastric muscle (with predominantly type II fibres), the heterogeneous fibre composition of the jaw-closing muscles probably reflects their more complicated activity pattern and functional requirements. The marked difference between the type I and the type II fibre diameters, type II fibres generally being smaller, might reflect evolutionary changes in the masticatory habits, such as adaptation to refined and soft food. The individual variability in fibre composition suggests various levels of utilization and varying ability to adapt to jaw-muscle hyperactivity, to resist fatigue.

Adenosine Triphosphatases↗

PubMed1983

Primary cortisol resistance: a familial syndrome and an animal model.

Primary cortisol resistance in man is a familial disease. It is characterized by increased plasma cortisol concentrations, high urinary free cortisol excretion, a normal circadian pattern of cortisol secretion, resistance to adrenal suppression by dexamethasone and absence of clinical stigmata of Cushing's syndrome. In its severe form, hypertension and hypokalemic alkalosis are present, owing to increased secretion of the sodium-retaining corticoids, corticosterone and deoxycorticosterone. In subjects with a less severe resistance to cortisol, there are no clinical abnormalities and the disease is revealed only by detailed examination of several parameters of cortisol metabolism. In the whole-cell assay (peripheral mononuclear leukocytes or fibroblasts) the glucocorticoid receptor shows a low affinity for dexamethasone. The receptor may be unsaturable as suggested by decreased receptor concentrations in broken-cell systems. Thus, generalized target-tissue resistance to cortisol, including the pituitary gland and the hypothalamus, is accompanied by a decreased negative feedback of the cortisol-ACTH feedback system resulting in increased ACTH secretion. This causes higher plasma cortisol to compensate for the end-organ resistance and also increases the production of adrenal mineralocorticoids, as by-products. Thus hypertension and hypokalemic alkalosis depends on the degree of the resistance. Cortisol resistance in many New World primate species is characterized by greatly increased plasma cortisol concentrations, decreased cortisol binding globulin capacity and affinity, high levels of plasma and urinary free cortisol, marked resistance of ACTH suppression by dexamethasone, and no physiologic evidence of glucocorticoid hormone excess. Target tissues have normal concentrations of glucocorticoid receptors with decreased affinity for dexamethasone. The New World primates, unlike man, have compensated for this cortisol resistance with intra-adrenal adaptations over the 50 million years of their evolutionary development. These primates also have abnormalities of other steroid hormone-receptor systems such as progesterone, estrogen, androgen and mineralocorticoid. In contrast, the human syndrome appears to be a recent mutation with pathophysiologic consequences.

Adrenal Gland Diseases↗

PubMed2005

Policy planning under uncertainty: efficient starting populations for simulation-optimization methods applied to municipal solid waste management.

Evolutionary simulation-optimization (ESO) techniques can be adapted to model a wide variety of problem types in which system components are stochastic. Grey programming (GP) methods have been previously applied to numerous environmental planning problems containing uncertain information. In this paper, ESO is combined with GP for policy planning to create a hybrid solution approach named GESO. It can be shown that multiple policy alternatives meeting required system criteria, or modelling-to-generate-alternatives (MGA), can be quickly and efficiently created by applying GESO to this case data. The efficacy of GESO is illustrated using a municipal solid waste management case taken from the regional municipality of Hamilton-Wentworth in the Province of Ontario, Canada. The MGA capability of GESO is especially meaningful for large-scale real-world planning problems and the practicality of this procedure can easily be extended from MSW systems to many other planning applications containing significant sources of uncertainty.

Computer Simulation↗

PubMed2006

Phylogenetic and evolutionary aspects of Paracoccidioides brasiliensis reveal a long coexistence with animal hosts that explain several biological features of the pathogen.

The habitat of the mycelial saprobic form of Paracoccidioides brasiliensis, which produces the infectious propagula, has not been determined and has proven difficult for mycologists to describe. The fungus has been rarely isolated from the environment, the disease has a prolonged latency period and no outbreaks have been reported. These facts have precluded the adoption of preventive measures to avoid infection. The confirmation of natural infections in nine-banded armadillos (Dasypus novemcinctus) with P. brasiliensis, in high frequency and wide geographic distribution, has opened new avenues for the study and understanding of its ecology. Armadillos belong to the order Xenarthra, which has existed in South America ever since the Paleocene Era (65 million years ago), when the South American subcontinent was still a detached land, before the consolidation of what is now known as the American continent. On the other hand, strong molecular evidence suggests that P. brasiliensis and other dimorphic pathogenic fungi--such as Blastomyces dermatitidis, Coccidioides immitis and Histoplasma capsulatum--belong to the family Onygenaceae sensu lato (order Onygenales, Ascomycota), which appeared around 150 million years ago. P. brasiliensis ecology and relation to its human host are probably linked to the fungal evolutionary past, especially its long coexistence with and adaptation to animal hosts other than Homo sapiens, of earlier origin. Instead of being a blind alley, the meaning of parasitism for dimorphic pathogenic fungi should be considered as an open two-way avenue, in which the fungus may return to the environment, therefore contributing to preserve its teleomorphic (sexual) and anamorphic (asexual) forms in a defined and protected natural habitat.

Animals↗

PubMed2006

A paradigm for viewing biologic systems as scale-free networks based on energy efficiency: implications for present therapies and the future of evolution.

A network constitutes an abstract description of the relationships among entities, respectively termed links and nodes. If a power law describes the probability distribution of the number of links per node, the network is said to be scale-free. Scale-free networks feature link clustering around certain hubs based on preferential attachments that emerge due either to merit or legacy. Biologic systems ranging from sub-atomic to ecosystems represent scale-free networks in which energy efficiency forms the basis of preferential attachments. This paradigm engenders a novel scale-free network theory of evolution based on energy efficiency. As environmental flux induces fitness dislocations and compels a new meritocracy, new merit-based hubs emerge, previously merit-based hubs become legacy hubs, and network recalibration occurs to achieve system optimization. To date, Darwinian evolution, characterized by innovation sampling, variation, and selection through filtered termination, has enabled biologic progress through optimization of energy efficiency. However, as humans remodel their environment, increasing the level of unanticipated fitness dislocations and inducing evolutionary stress, the tendency of networks to exhibit inertia and retain legacy hubs engender maladaptations. Many modern diseases may fundamentally derive from these evolutionary displacements. Death itself may constitute a programmed adaptation, terminating individuals who represent legacy hubs and recalibrating the network. As memes replace genes as the basis of innovation, death itself has become a legacy hub. Post-Darwinian evolution may favor indefinite persistence to optimize energy efficiency. We describe strategies to reprogram or decommission legacy hubs that participate in human disease and death.

Animals↗

PubMed2006

Sex differences in OCD symptomatology: an evolutionary perspective.

Some evolutionists have construed obsessive-compulsive disorder (OCD) as the over-activation of warning systems in areas of evolutionary import. Using evolutionary theorizing, it is posited here that sex differences in the instantiation of specific obsessions and/or compulsions might correspond to sex-specific differences in the evolutionary import of the domain to which the particular symptom maps onto (e.g., mating versus parenting). Even in instances where no sex differences are found in the incidence of a particular obsession and/or compulsion (e.g., the extent to which men and women might suffer from intrusive thoughts), an evolutionary perspective might nonetheless propose that the contents of such thoughts map onto sex-specific adaptive concerns (e.g., social status and appearance-related concerns for men and women, respectively). An evolutionary approach might help not only in explaining sex differences in OCD phenomenology but also in elucidating within-sex manifestations of OCD symptoms (e.g., the shifting strength of contamination fears across a woman's menstrual cycle). The current evolutionary perspective not only provides an integrative ultimate-level meta-framework in understanding previously-found sex differences in OCD but also it permits OCD researchers to propose innovative hypotheses that otherwise might have been unlikely to be posited if one were to strictly focus on a proximate exploration of OCD. Cross-cultural clinical data, originating from a heterogeneous set of cultures and highlighting universal patterns of sex-specific OCD symptomatology, would provide a strong test of the posited hypotheses.

Biological Evolution↗

PubMed2004

Thioester-containing proteins and insect immunity.

Here, we discuss the role of thioester-containing proteins in innate immune responses of insects. TEPs are represented by multi-member families both in the fruitfly, Drosophila melanogaster, and in the mosquito, Anopheles gambiae. Phylogenetic analysis of the family suggests that in these two dipteran species evolution of TEPs followed independent scenarios as a result of specific adaptation to distinct ecological environments. Research on these two relatively simple model systems, which lack adaptive immunity, may provide new insights into the evolutionary origins and functions of this important protein family.

Animals↗

PubMed2006

Functional evo-devo.

Functional factors such as optimal design and adaptive value have been the central concern of evolutionary biology since the advent of the New Synthesis. By contrast, evolutionary developmental biology (evo-devo) has concentrated primarily on structural factors such as the ways in which body parts can be built. These different emphases have stood in the way of an integrated understanding of the role of development in evolution. Here, we try to bridge this gap by outlining the relevance of functional factors in evo-devo. We use modularity and the view of development as a flexible evolutionary system to outline a unified perspective that includes both structural and functional aspects.

Animals↗

PubMed2001

[Heterochronia via procrustean superimposition: application to the skulls of Homonidae primates].

The procrustes superimposition method is well adapted to heterochronic studies in the field of evolutionary biology. 1) The procrustes method gives a precise and mathematical definition of two of the three heterochronic variables: size and shape. 2) It allows us to describe complex anatomical structures and thus to analyse the whole structure and not just to proceed trait by trait. 3) The approach is statistical and the different hypotheses and results may be statistically tested. 4) When applied to heterochronies the method allows us to test if there is a common shape change related to allometry. In the present study of three species of Hominoid primates, the procrustes superimposition reveals that various heterochronic processes are simultaneously present. Size-age-shape dissociations between species, already present in the first ontogenetic stage, are amplified with growth until adult stage. As compared with that of the chimpanzee, the growth of the gorilla skull is accelerated in terms of size-shape covariation and size alone. The growth of the human skull is neotenic as compared with that of the apes.

Adult↗

PubMed1997

From vigilance to violence: mate retention tactics in married couples.

Although much research has explored the adaptive problems of mate selection and mate attraction, little research has investigated the adaptive problem of mate retention. We tested several evolutionary psychological hypotheses about the determinants of mate retention in 214 married people. We assessed the usage of 19 mate retention tactics ranging from vigilance to violence. Key hypothesized findings include the following: Men's, but not women's, mate retention positively covaried with partner's youth and physical attractiveness. Women's, but not men's, mate retention positively covaried with partner's income and status striving. Men's mate retention positively covaried with perceived probability of partner's infidelity. Men, more than women, reported using resource display, submission and debasement, and intrasexual threats to retain their mates. Women, more than men, reported using appearance enhancement and verbal signals of possession. Discussion includes an evolutionary psychological analysis of mate retention in married couples.

Adolescent↗

PubMedDate not supplied

Analyzing evolutionary patterns in amniote embryonic development.

Heterochrony (differences in developmental timing between species) is a major mechanism of evolutionary change. However, the dynamic nature of development and the lack of a universal time frame makes heterochrony difficult to analyze. This has important repercussions in any developmental study that compares patterns of morphogenesis and gene expression across species. We describe a method that makes it possible to quantify timing shifts in embryonic development and to map their evolutionary history. By removing a direct dependence on traditional staging series, through the use of a relative time frame, it allows the analysis of developmental sequences across species boundaries. Applying our method to published data on vertebrate development, we identified clear patterns of heterochrony. For example, an early onset of various heart characters occurs throughout amniote evolution. This suggests that advanced (precocious) heart development arose in evolutionary history before endothermy. Our approach can be adapted to analyze other forms of comparative dynamic data, including patterns of developmental gene expression.

Age Factors↗

PubMedDate not supplied

Generalized norms of reaction for ecological developmental biology.

A standard norm of reaction (NoR) is a graphical depiction of the phenotypic value of some trait of an individual genotype in a population as a function an environmental parameter. NoRs thus depict the phenotypic plasticity of a trait. The topological properties of NoRs for sets of different genotypes can be used to infer the presence of (nonlinear) genotype-environment interactions. Although it is clear that many NoRs are adaptive, it is not yet settled whether their evolutionary etiology should be explained by selection on the mean phenotypic trait values in different environments or whether there are specific genes conferring plasticity. If the second alternative is true, the NoR is itself an object of selection. Generalized NoRs depict plasticity at the level of populations or subspecies within a species, species within a genus, or taxa at higher levels. Historically, generalized NoRs have routinely been drawn though rarely explicitly recognized as such. Such generalized NoRs can be used to make evolutionary inferences at higher taxonomic levels in a way analogous to how standard NoRs are used for microevolutionary inferences.

Developmental Biology↗

PubMed2001

Microbial disease in humans: A genomic perspective.

The approach of whole-genome shotgun sequencing coupled with the availability of computational algorithms to facilitate the assembly, gene prediction, and functional annotation of entire genomes has sparked a revolution in our understanding of the biology of free-living organisms. More than 40 bacterial genomes have been sequenced to date, of which several are important human pathogens. The capacity to sequence and assemble entire genomes of bacteria, pathogenic protozoans, and fungi in a rapid and cost-effective way has energized every aspect of microbial science. Comparative genome analysis allows us to dissect the evolutionary forces at work and provides insights into adaptations of microbes to their unique ecological niches. Factors that shape host-pathogen interactions and their outcomes include genetic polymorphisms in the microbial pathogen and host, both of which can impact on microbial virulence or host immune responses to infection. The availability of the genome sequence of entire organisms, together with the use of high-throughput sequence-based genomic technologies to define microbial and host physiological states, provides the unparalleled opportunity to better define clinical outcomes in the field of infectious diseases. There is one overarching lesson: completion of the genomic sequence of any species answers many questions, while at the same time it invites totally new questions.

Animals↗

PubMed1996

Ecological factors rather than temporal factors dominate the evolution of vesicular stomatitis virus.

Vesicular stomatitis New Jersey virus (VSV-NJ) is a rhabdovirus that causes economically important disease in cattle and other domestic animals in endemic areas from southeastern United States to northern South America. Its negatively stranded RNA genome is capable of undergoing rapid evolution, which allows phylogenetic analysis and molecular epidemiology studies to be performed. Previous epidemiological studies in Costa Rica showed the existence of at least two distinct ecological zones of high VSV-NJ activity, one located in the highlands (premontane tropical moist forest) and the other in the lowlands (tropical dry forest). We wanted to test the hypothesis that the viruses circulating in these ecological zones were genetically distinct. For this purpose, we sequenced the hypervariable region of the phosphoprotein gene for 50 VSV-NJ isolates from these areas. Phylogenetic analysis showed that viruses from each ecological zone had distinct genotypes. These genotypes were maintained in each area for periods of up to 8 years. This evolutionary pattern of VSV-NJ suggests an adaptation to ecological factors that could exert selective pressure on the virus. As previous data indicated an absence of virus adaptation to factors related to the bovine host (including immunological pressure), it appears that VSV genetic divergence represents positive selection to adapt to specific vectors and/or reservoirs at each ecological zone.

Animals↗