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PubMed2000

Shapes in the shadow: evolutionary dynamics of morphogenesis.

This article investigates the evolutionary dynamics of morphogenesis. In this study, morphogenesis arises as a side-effect of maximization of number of cell types. Thus, it investigates the evolutionary dynamics of side-effects. Morphogenesis is governed by the interplay between differential cell adhesion, gene-regulation, and intercellular signaling. Thus, it investigates the potential to generate complex behavior by entanglement of relatively "boring" processes, and the (automatic) coordination between these processes. The evolutionary dynamics shows all the hallmarks of evolutionary dynamics governed by nonlinear genotype phenotype mapping: for example, punctuated equilibria and diffusion on neutral paths. More striking is the result that interesting, complex morphogenesis occurs mainly in the "shadow" of neutral paths which preserve cell differentiation, that is, the interesting morphologies arise as mutants of the fittest individuals. Characteristics of the evolution of such side-effects in the shadow appear to be the following: (1) The specific complex morphologies are unique (or at least very rare) among the set of de novo initiated evolutionary histories. (2) Similar morphologies are reinvented at large temporal distances during one evolutionary history and also when evolution is restarted after the main cell differentiation pattern has been established. (3) A mosaic-like evolution at the morphological level, where different morphological features occur in many combinations, while at the genotypic level recombination is not implemented and genotypes diverge linearly and at a constant rate.

Animals↗
PubMed2003

Extinction and re-evolution of similar adaptive types (ecomorphs) in Cenozoic North American ungulates and carnivores reflect van der Hammen's cycles.

Numerous patterns in periodicity (e.g., climate, extinction, and sedimentary cycles) and evolutionary change (e.g., chronofaunas and coordinated stasis) have been described based on aspects of the geologic record. Recently, convergent occurrences of faunal types or "repeating faunas" have received attention, but a highly specific, iterative pattern was first reported over 40 years ago. In the late 1950s, van der Hammen described climatic/floral cycles on the order of six million years based on a succession of A, B, and C pollen community types in South America. These A-B-C cycles are also seen in the replacement pattern of particular carnivore and ungulate adaptive types in Cenozoic North America as reported by Martin in the 1980s. For example, in the last 36 million years, there were four iterations of a sabertooth cat ecomorph independently evolving, dominating the niche through an A-B-C cycle, and then going extinct. Here we show further support for the existence of these cycles in the dominance turnover in hippo and dog ecomorphs in the North American Cenozoic. Shared patterns of extinction and re-evolution of adaptive types among plants and mammals across two continents suggest a global mechanism, which appears to be climatic change. Iterative climatic cycles of various scales may form a predictive framework for understanding fundamental patterns in the geologic record, such as radiations, extinction, rates of change, convergence, and sedimentary cycles.

Acclimatization↗
PubMed2005

Increased phosphorylation and decreased level of IkappaBalpha during aging in rat liver.

Nuclear factor kappa B (NFkappaB) is an evolutionary conserved transcription factor, which coordinates various metabolic processes triggered by innate and adaptive immune responses. Supakar et al. (J. Biol. Chem. 270: 837-842, 1995) had reported a 10-fold increase in DNA binding activity of NFkappaB in liver of old rats. In this study, we have analyzed the changes in the level of NFkappaB, inhibitor of NFkappaB (IkappaBalpha), phosphorylated-IkappaBalpha (p-IkappaBalpha) and IkappaB kinase (IKK) in rat liver during aging by reverse transcription polymerase chain reaction and/or western blotting. Here we demonstrate that there is an age-dependent increase in the level of p-IkappaBalpha with concomitant decrease in the level of IkappaBalpha, which may be correlated with increased inflammation, oxidative stress and higher level of activated NFkappaB in rat liver in old age.

Aging↗
PubMed1990

Alkaline phosphatase isozymes: recent progress.

The past few years have witnessed the reports of significant new events in alkaline phosphatase (AP) isozymes. The cloning of the relevant genes and their nucleotide sequencing have all been accomplished. As a group, the genes for the intestinal, germ cell and placental isozymes have considerable sequence similarity; it is noteworthy that they occupy vicinal positions on chromosome 2, while the tissue unspecific AP gene is located on chromosome 1. The latter makes evolutionary lineage and instances of coordinate expression understandable. Another new development is the demonstration of a phosphatidyl inositol glycan tail on the C-terminus of these chromosome-2 AP genes. This is the major membrane insertion mechanism for AP, which is a cell surface membrane enzyme. This information may be helpful in understanding the phenomenon of the depletion of intestinal mucosal AP during fat absorption. Finally, a discussion has been focussed on recent studies on seminoma and AP, including immunodetection and immunoradiotherapy.

Alkaline Phosphatase↗
PubMed2007

Keys and the crisis in taxonomy: extinction or reinvention?

Dichotomous keys that follow a single pathway of character state choices to an end point have been the primary tools for the identification of unknown organisms for more than two centuries. However, a revolution in computer diagnostics is now under way that may result in the replacement of traditional keys by matrix-based computer interactive keys that have many paths to a correct identification and make extensive use of hypertext to link to images, glossaries, and other support material. Progress is also being made on replacing keys entirely by optical matching of specimens to digital databases and DNA sequences. These new tools may go some way toward alleviating the taxonomic impediment to biodiversity studies and other ecological and evolutionary research, especially with better coordination between those who produce keys and those who use them and by integrating interactive keys into larger biological Web sites.

Animals↗
PubMed2006

Comparative mapping of cattle chromosome 19: cytogenetic localization of 19 BAC clones.

Here we present the results of fluorescent in situ hybridization (FISH) mapping of a set of cattle BAC clones preselected for assignment on cattle chromosome 19 (BTA19). The BAC clones were anchored to human chromosome 17 (HSA17) sequences by BLASTn similarity search of cattle BAC-ends against the human genome sequence (NCBI build 33). Five blocks of homologous synteny were defined in the comparative map of BTA19 and HSA17 built with FISH data and the human genome coordinates. The positions for four evolutionary breakpoints in the bovine and human chromosomes were identified. Comparison of the FISH comparative map with previously published comparative RH, physical, and cytogenetic maps of BTA19 did not reveal major conflicts and allowed for the extension of the boundaries of homology between BTA19 and HSA17. Comparative analysis of HSA17, BTA19, and mouse chromosome 11 (MMU11) demonstrates that most likely mice retain the ancestral organization of the synteny group, and both cattle and human chromosomes underwent several major internal rearrangements after the divergence of Primates, Rodentia, and Cetartiodactyla.

Animals↗
PubMed1994

The basics of EDI (electronic data interchange): a pathway to the information highway.

With EDI, patients such as Jane Russo can focus not on the time-consuming and often confusing business of benefit coordination, but on getting well. Similarly, the registration clerk's job is simplified thanks to a single electronic link that provides the information needed to perform his or her job accurately and efficiently. The health information management department can use EDI to maintain authority over the release of information and make the process of transferring patient information more expeditious. As EDI further evolves into the clinical arena, it will enhance care providers' access to longitudinal patient clinical records. In addition, the information highway will provide access to better information for quality assessment, outcomes management, and the development of clinical guidelines. With access to the information highway, healthcare providers, payers, and employers can take an evolutionary leap in their efforts toward coordinating truly patient-centered, high-quality care.

Computer Communication Networks↗
PubMed2005

Thermodynamical interpretation of evolutionary dynamics on a fitness landscape in an evolution reactor, II.

In our previous report [Aita, T., Morinaga, S., Hosimi, Y., 2004. Thermodynamical interpretation of evolutionary dynamics on a fitness landscape in an evolution reactor I. Bull. Math. Biol. 66, 1371-1403], an analogy between thermodynamics and adaptive walks on a Mt. Fuji-type fitness landscape in an artificial selection system was presented. Introducing the 'free fitness' as the sum of a fitness term and an entropy term and 'evolutionary force' as the gradient of free fitness on a fitness coordinate, we demonstrated that the adaptive walk (=evolution) is driven by the evolutionary force in the direction in which free fitness increases. In this report, we examine the effect of various modifications of the original model on the properties of the adaptive walk. The modifications were as follows: first, mutation distance d was distributed obeying binomial distribution; second, the selection process obeyed the natural selection protocol; third, ruggedness was introduced to the landscape according to the NK model; fourth, a noise was included in the fitness measurement. The effect of each modification was described in the same theoretical framework as the original model by introducing 'effective' quantities such as the effective mutation distance or the effective screening size.

Algorithms↗
PubMed2000

Complementarity theory: why human social capacities evolved to require cultural complements.

This article introduces complementarity theory, which explains the psychology of cultural diversity as a product of evolved social proclivities that enable-and require-people to coordinate action in culture-specific ways. The theory presents evolutionary processes and psychological mechanisms that may account for the cultural variability of social coordination devices such as language, relational models, rituals, moral interpretations of misfortune, taboos, religion, marriage, and descent systems. Human fitness and well-being depend on social coordination characterized by complementarity among the participants' actions. This complementarity is based primarily on coordination devices derived from the conjunction of cultural paradigms and specific, highly structured, evolved proclivities. The proclivities have no adaptive value without the paradigms, and the paradigms have no meaning without the proclivities. They are coadapted to function together. Operating in conjunction with each other, proclivities and paradigms jointly define the generative structures for meaningful coordination of social interaction in each particular culture.

Journal Article↗
PubMed2003

Linking development and aging.

Evolutionary theory predicts that the different life stages of organisms are coordinated to achieve maximal reproductive output. Moreover, aging can be seen as an evolutionary side effect of this selective process that applies to many living organisms. Hence, genetic, developmental, and physiological mechanisms resulting from this selection are expected to be conserved in diverse lineages. The insulin/insulin-like growth factor signaling (INS) pathway appears to be such a mechanism that regulates life span and reproduction in a variety of model organisms. Here I argue that the experimental tools of environmental manipulation and gene by environment interaction should be used more often both during the experimental organism's development and its adult life. This approach will help us to fully understand the functions of longevity-determining pathways and will determine the life stages during which these pathways exert their effects on adult life. These points are raised because of a recent Aging Cell publication by Tu and Tatar, in which the larval food environment was manipulated to determine the effects on adult reproduction, life span, aging, and INS. The results of this study are a promise of the usefulness of this approach for understanding the aging process.

Aging↗
PubMed2005

Evolution of nuclearly encoded mitochondrial genes in Metazoa.

All Metazoan nuclear genomes underwent a continuous process of both complete and partial genetic material gain and loss. The forces modulating these events are also subject to the strict interaction between nuclear and mitochondrial (mt) genome. In this context we investigate the evolution of nuclear genes encoding proteins which target the mitochondrion, with a particular attention to genes involved in oxidative phosphorylation (OXPHOS), one of the most ancient and conserved functions. To examine thoroughly the evolutionary strategies that preserve OXPHOS and coordinate the two cellular genomes, a comparative analysis has been carried out for 78 OXPHOS gene families in several Metazoa (insects, tunicates, fishes and mammals). We demonstrate that the duplication rate of OXPHOS genes increases passing from invertebrates to vertebrates consistently with the total increase in genome size, but all species are prone to negatively select OXPHOS duplicates compared to the general trend of nuclear gene families. These results are consistent with the 'balance hypothesis' and, at least in insects, the expression of duplicate genes is low and strongly testis-biased.

Animals↗
PubMed2005

Retrieval improvement is induced by water shortage through angiotensin II.

Angiotensin II (ANGII) has an evolutionary preserved role in determining adaptative responses to water-shortages. In addition, it has been shown to modulate diverse phases of memory. Still, it is not clear whether ANGII improves or spoils memory. We demonstrated that endogenous angiotensins enhance consolidation of a long-term associative memory in the crab Chasmagnathus and that water shortage improves memory consolidation through brain ANGII actions. Here, we show that weakly trained crabs, when water-deprived, exhibit enhanced retrieval. Subsequently, memory retention is indistinguishable from that of strongly trained crabs. ANGII, but not angiotensin IV, is a necessary and sufficient condition for such enhancing effect. We conclude that ANGII released due to water shortage leads to enhanced memory retrieval. Thus, it seems that ANGII has an evolutionary preserved role as a multifunction coordinator that enables an adaptative response to water-shortage. The facilitation of memory consolidation and retrieval would be among those coordinated functions.

Adaptation, Physiological↗
PubMed1996

Does stereopsis matter in humans?

Stereopsis has been one of the most popular fields of vision research for well over a century and is routinely measured in clinical practice, yet its functional significance has been largely neglected. Stereopsis is disrupted by blur, amblyopia and strabismus and is of potential value as a means of indirect screening for visual disorders in childhood. However, evidence for the functional effects of stereoscopic deficits is sparse. Recent investigations indicate that binocularity is an advantage in certain tasks, especially in the comprehension of complex visual presentations and those requiring good hand-eye coordination. The assumption derived from the evolutionary theory that stereopsis represents an adaptation by primates to arboreal life needs to be questioned. While the functional aspects of stereopsis are still not fully understood the direction that future research should take to unravel this important issue is apparent.

Adult↗
PubMed1999

Steroid sensitive sites in the avian brain: does the distribution of the estrogen receptor alpha and beta types provide insight into their function?

Studies in avian species have often been useful in elucidating basic concepts relevant to the regulation of reproductive behaviors by sex steroid hormones. Once a link between a steroid hormone and a behavioral response has been established, one can use the localization of steroid hormone receptors in the brain to facilitate the identification of neural circuits that control behavior. The recent identification of a second type of estrogen receptor called estrogen receptor beta or ERbeta has raised new issues about the action of steroid hormones in the brain. A hypothesis has been proposed by Kuiper et al. [1998] based on studies in mammalian species suggesting that ERalpha (the name given to the ER that was previously described) is important for reproduction while ERbeta is more important for non-reproductive functions. In this paper we apply this hypothesis more generally by examining possible functions of ERbeta in avian species. We have initiated studies of the ERbeta in the brain of two avian species, the Japanese quail (Coturnix japonica) and the European starling (Sturnus vulgaris). ERbeta was cloned in both species and the mRNA for this receptor type was localized in the brain employing in situ hybridization histochemistry methods. In both species ERbeta was found to be diffusely present in telencephalic areas consistent with a role for this receptor subtype in cognitive functions. However, ERbeta mRNA was also found in many brain areas that are traditionally thought to be important in the regulation of reproductive functions such as the preoptic region, the bed nucleus of the stria terminalis and the nucleus taeniae. Of the two receptor types, only mRNA for ERalpha was observed in the telencephalic vocal control nucleus HVc of male starlings. Steroid receptors in this nucleus are thought to be an example of an evolutionary specialization that has evolved to coordinate the production of courtship vocalizations with other aspects of reproduction. The lack of ERbeta mRNA expression in HVc is consistent with the hypothesis that ERalpha is preferentially involved in reproductive behaviors while ERbeta is involved in the steroid regulation of other neural functions. However, the widespread occurrence of ERbeta in other nuclei involved in reproductive function suggests that one must be cautious about the general applicability of the above hypothesis until more is known about ERbeta function in these other nuclei.

Animals↗
PubMed1991

Co-regulation of a gene homologous to early light-induced genes in higher plants and beta-carotene biosynthesis in the alga Dunaliella bardawil.

Dunaliella bardawil, a unicellular green alga that can be induced to accumulate massive amounts of beta-carotene, is particularly suitable for studies of carotenogenesis regulation and its links to developmental and adaptive processes in the chloroplast. A cDNA clone corresponding to a transcript accumulating coordinately with carotenogenesis induction was isolated by differential hybridization of a cDNA library made from intensely illuminated cells. This transcript was also abundant in algal mutants able to accumulate beta-carotene under relatively low light intensity. DNA sequence analysis indicates that cbr (for carotene biosynthesis-related) is closely related to early light-induced genes (elip) of higher plants. Similarity also exists between repeated oligopeptide motifs in Cbr and Cab proteins of photosystems I and II. Three upstream direct repeats in cbr include an octamer and hexamer related to mammalian sterol regulatory elements. The relationship between cbr transcript and beta-carotene accumulation, the structural similarity between Cbr and Cab proteins, and the presence of potential SRE-1 elements lead us to propose that Cbr represents novel carotenoid binding proteins, whose synthesis might be coordinated with carotenogenic enzymes via an evolutionary conserved regulatory mechanism.

Amino Acid Sequence↗
PubMed2006

An evolutionary model for identifying genetic adaptation to high altitude.

Coordinated maternal/fetal responses to pregnancy are required to ensure continuous O2 delivery to the developing organism. Mammals employ distinctive reproductive strategies that afford their young an improved chance of survival through the completion or the reproductive period. Thus, mortality prior to the end of the reproductive period is concentrated in the earliest phases of the lifecycle. At high altitude, fetal growth restriction reduces birth weight and likely compromises survival during the early postnatal period. Population variation in the frequency of the altitude-associated increase in intrauterine growth restriction (IUGR) demonstrates that multigenerational Tibetan and Andean high-altitude populations are protected compared with shorter duration, European or Han (Chinese) residents. This experiment of nature permits testing the hypothesis that genetic factors (a) influence susceptibility to altitude-associated IUGR, (b) act on maternal vascular adjustments to pregnancy determining uteroplacental blood flow, and (c) involve genes which regulate and/or are regulated by hypoxia-inducible factors (HIFs). Serial, studies during pregnancy as well as postpartum in Andean and European residents of high (3600 m) and low (300 m) altitude will permit evaluation of whether uteroplacental O2 delivery is lower in the European than Andean women and, if so, the physiological factors responsible. Comparisons of HIF-targeted vasoactive substances and SNPs in or near HIF-regulatory or targeted genes will permit determination of whether these regions are distinctive in the Andean population. Studies coupling genetic and genomic approaches with more traditional physiological measures may be productively employed for determining the genetic mechanisms influencing physiological adaptation to high altitude.

Adolescent↗
PubMed2006

Octopuses use a human-like strategy to control precise point-to-point arm movements.

One of the key problems in motor control is mastering or reducing the number of degrees of freedom (DOFs) through coordination. This problem is especially prominent with hyper-redundant limbs such as the extremely flexible arm of the octopus. Several strategies for simplifying these control problems have been suggested for human point-to-point arm movements. Despite the evolutionary gap and morphological differences, humans and octopuses evolved similar strategies when fetching food to the mouth. To achieve this precise point-to-point-task, octopus arms generate a quasi-articulated structure based on three dynamic joints. A rotational movement around these joints brings the object to the mouth . Here, we describe a peripheral neural mechanism-two waves of muscle activation propagate toward each other, and their collision point sets the medial-joint location. This is a remarkably simple mechanism for adjusting the length of the segments according to where the object is grasped. Furthermore, similar to certain human arm movements, kinematic invariants were observed at the joint level rather than at the end-effector level, suggesting intrinsic control coordination. The evolutionary convergence to similar geometrical and kinematic features suggests that a kinematically constrained articulated limb controlled at the level of joint space is the optimal solution for precise point-to-point movements.

Animals↗
PubMed1992

Brainstem control of orienting movements: intrinsic coordinate systems and underlying circuitry.

A fundamental issue in the understanding of how the nervous system processes information is the way in which sensory information is used to initiate and guide movements. Recent progress has been made by taking an information processing approach in which information--for example, the spatial location of an object towards which an animal will orient--is tracked through the nervous system from sensory to motor levels. In this approach, neurally encoded information is characterized in terms of its representation within a neural or intrinsic coordinate system or set of neural coding parameters. For example, the retina codes spatial location in terms of the location of activity on the retinal surface, whereas motoneurons code spatial location in terms of the pulling directions of the muscles they activate. In between these two peripheral stages, the information passes through intermediate coordinate systems. These intermediate coordinate systems can be characterized by recording or altering the activity of small groups of neurons while an animal is performing a well-defined sensorimotor task. Spatial location information is used to guide orienting movements, those movements made by the eyes, ears, head, or body which function to center an object of interest in the animal's visual field. The optic tectum and forebrain, their connections to the medial mesencephalic and rhombencephalic brainstem tegmental cell groups, and subsequent connections to brainstem motor nuclei and spinal cord are employed to control fundamental aspects of this behavior. Studies reviewed herein indicate that following the retinotopic coding of spatial location in the retina and tectum, spatial location information appears to enter a different coordinate system at tegmental levels in which spatial aspects of orienting movement are coded in terms of their discrete horizontal and vertical components. This Cartesian coordinate system is an example of an abstract neural coordinate system, in that it is a simple, low-dimensional representation of spatial location which differs greatly from both sensory and motor representations. Also, this Cartesian representation may be common to many orienting movements, yet it appears to differ from the coordinate systems controlling other movement types such as stabilization or phasic movements. This suggests an hypothesis in which coordinate systems, especially at intermediate levels of processing, may be organized according to behavioral task as opposed to being determined by the particular sensory or motor system involved in the behavior. Understanding the evolutionary heritage and computational function of abstract neural coordinate systems, and the relation between different coordinate systems and behavioral tasks may be useful in understanding general aspects of sensory information processing and motor control.

Animals↗