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Results for “convergent evolution”

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PubMed2005

[Neuropsychiatric Inventory-Nursing Home version (NPI-NH): Spanish validation].

INTRODUCTION: The Neuropsychiatric Inventory-Nursing Home version (NPI-NH) is a screening instrument to be used by the nursing staff to evaluate neuropsychiatric symptoms in dementia patients in the nursing home setting. The aim of the present study was to validate the NPI-NH in Spanish. METHODS: We assessed the validity of the NPI-NH in 80 patients who were also nursing home residents, comparing the responses of nursing home staff on the NPI-NH with that filled out by the external observer. We developed a crossed validated form between the Neuropsychiatric Inventory-Questionnaire (NPI-Q) and both NPI-NH. We determined the concurrent validity of the domains "depression" and "agitation/aggression" of the NPI-NH with the Cohen-Mansfield Agitation Inventory (IAACM, Spanish version) and the Hamilton Depression Rating Scale (HDRS). RESULTS: Among the totals of the NPI-NH of the nursing staff and the NPI-Q, the convergent validity was r = 0.536 and r = 0.669 for the occupational disruptiveness scale (distress in NPI-Q). The Pearson correlation index between the NPI-Q and NPI-NH of the observations was r = 0.342. The convergent validity between the NPINH of the nursing home staff and NPI-NH of the observers with the Pearson correlation index was r = 0.274. CONCLUSIONS: The NPI-NH Spanish version offers the possibility to use a screening tool for detecting neuropsychiatric symptoms in dementia patients in the nursing home setting. It should be administered by adequately trained staff to avoid limitations in the evolutive control of behavioral changes.

Aged↗

PubMed1996

[Prevention of cell death by Bcl-2 family genes].

Apoptosis is a tightly regulated and evolutionally conserved suicide mechanism. Proteases encoded by ced-3 and ice gene family appear to play a key role in driving apoptosis. On the other hand, Bcl-2 and its relatives have the ability to inhibit apoptosis induced by a variety of stimuli, indicating that Bcl-2 family negatively regulates a key event in a common pathway of apoptosis in which different apoptotic signals finally converge, although the biochemical basis of the function remains unknown. Here, I overview Bcl-2 gene family, and discuss the molecular basis of anti-apoptotic activity of Bcl-2, focusing on our recent findings on Bcl-2 function in mitochondria.

Animals↗

PubMed2001

A molecular model for the evolution of endothermy in the theropod-bird lineage.

Ectothermy is a primitive state; therefore, a shared common ancestor of crocodiles, dinosaurs, and birds was at some point ectothermic. Birds, the extant descendants of the dinosaurs, are endothermic. Neither the metabolic transition within this lineage nor the place the dinosaurs held along the ectothermic-endothermic continuum is defined. This paper presents a conceptual model for the evolution of endothermy in the theropod-bird lineage. It is recognized that other animals (some fish, insects, etc.) are functionally endothermic. However, endothermy in other clades is beyond the scope of this paper, and we address the onset of endothermy in only the theropod/bird clade. The model begins with simple changes in a single gene of a common ancestor, and it includes a series of concomitant physiological and morphological changes, beginning perhaps as early as the first archosaurian common ancestor of dinosaurs and crocodiles. These changes continued to accumulate within the theropod-avian lineage, were maintained and refined through selective forces, and culminated in extant birds. Metabolic convergence or homoplasy is evident in the inherent differences between the endothermy of mammals and the endothermy of extant birds. The strength and usefulness of this model lie in the phylogenetic, genetic, evolutionary, and adaptive plausibility of each of the suggested developmental steps toward endothermy. The model, although conceptual in nature, relies on an extensive knowledge base developed by numerous workers in each of these areas. In addition, the model integrates known genetic, metabolic, and developmental aspects of extant taxa that phylogenetically bracket theropod dinosaurs for comparison with information derived from the fossil record of related extinct taxa.

Adaptation, Physiological↗

PubMed2000

Acquisition of a potential marker for insect transformation: isolation of a novel alcohol dehydrogenase gene from Bactrocera oleae by functional complementation in yeast.

The alcohol dehydrogenase genes make up one of the best studied gene families in Drosophila, both in terms of expression and evolution. Moreover, alcohol dehydrogenase genes constitute potential versatile markers in insect transformation experiments. However, due to their rapid evolution, these genes cannot be cloned from other insect genera by DNA hybridization or PCR-based strategies. We have therefore explored an alternative strategy: cloning by functional complementation of appropriate yeast mutants. Here we report that two alcohol dehydrogenase genes from the medfly Ceratitis capitata can functionally replace the yeast enzymes, even though the medfly and yeast genes have evolved independently, acquiring their enzymatic function convergently. Using this method, we have cloned an alcohol dehydrogenase gene from the olive pest Bactrocera oleae. We conclude that functional complementation in yeast can be used to clone alcohol dehydrogenase genes that are unrelated in sequence to those of yeast, thus providing a powerful tool for isolation of dominant insect transformation marker genes.

Alcohol Dehydrogenase↗

PubMed1999

Recursive cumulative meta-analysis: a diagnostic for the evolution of total randomized evidence from group and individual patient data.

Meta-analyses of randomized evidence may include published, unpublished, and updated data in an ongoing estimation process that continuously accommodates more data. Synthesis may be performed either with group data or with meta-analysis of individual patient data (MIPD). Although MIPD with updated data is considered the gold standard of evidence, there is a need for a careful study of the impact different sources of data have on a meta-analysis and of the change in the treatment effect estimates over sequential information steps. Unpublished data and late-appearing data may be different from early-appearing data. Updated information after the end of the main study follow-up may be affected by cross-overs, missing information, and unblinding. The estimated treatment effect may thus depend on the completeness and updating of the available evidence. To address these issues, we present recursive cumulative meta-analysis (RCM) as an extension of cumulative metaanalysis. Recursive cumulative meta-analysis is based on the principle of recalculating the results of a cumulative meta-analysis with each new or updated piece of information and focuses on the evolution of the treatment effect as a more complete and updated picture of the evidence becomes available. An examination of the perturbations of the cumulative treatment effect over sequential information steps may signal the presence of bias or heterogeneity in a meta-analysis. Recursive cumulative meta-analysis may suggest whether there is a true underlying treatment effect to which the meta-analysis is converging and how treatment effects are sequentially altered by new or modified evidence. The method is illustrated with an example from the conduct of an MIPD on acyclovir in human immunodeficiency virus infection. The relative strengths and limitations of both metaanalysis of group data and MIPD are discussed through the RCM perspective.

Acyclovir↗

PubMed2005

Large amplitude quantum mechanics in polyatomic hydrides. I. A particles-on-a-sphere model for XH(n).

A framework is presented for converged quantum mechanical calculations on large amplitude dynamics in polyatomic hydrides (XH(n)) based on a relatively simple, but computationally tractable, "particles-on-a-sphere" (POS) model for the intramolecular motion of the light atoms. The model assumes independent two-dimensional (2D) angular motion of H atoms imbedded on the surface of a sphere with an arbitrary interatomic angular potential. This assumption permits systematic evolution from "free rotor" to "tunneling" to "quasi-rigid" polyatomic molecule behavior for small, but finite, values of total angular momentum J. This work focuses on simple triatom (n=2) and tetratom (n=3) systems as a function of interatomic potential stiffness, with explicit consideration of H2O, NH3, and H3O+ as limiting test cases. The POS model also establishes the necessary mathematical groundwork for calculations on dynamically much more challenging XH(n) species with n>3 (e.g., models of CH5+) where such a reduced dimensionality approach offers prospects for being quantum mechanically tractable at low J values (i.e., J=0, 1, 2) characteristic of supersonic jet expansion conditions.

Journal Article↗

PubMed2005

The Late Triassic pseudosuchian Revueltosaurus callenderi and its implications for the diversity of early ornithischian dinosaurs.

A new discovery of skeletons of Revueltosaurus callenderi from the Upper Triassic Chinle Formation of Petrified Forest National Park, Arizona clearly shows that Revueltosaurus is not an ornithischian dinosaur as previously supposed. Features such as the presence of a postfrontal, crocodile-normal ankle and paramedian osteoderms with anterior bars place R. callenderi within the Pseudosuchia, closer to crocodylomorphs than to dinosaurs. Therefore, dental characters previously used to place Revueltosaurus within the Ornithischia evolved convergently among other archosaur taxa, and cannot be used to diagnose ornithischian dinosaur teeth. As a result, all other putative North American Late Triassic ornithischians, which are all based exclusively on teeth, are cast into doubt. The only reasonably well-confirmed Late Triassic ornithischians worldwide are Pisanosaurus mertii and an unnamed heterodontosaurid from Argentina. This considerably changes the understanding of early dinosaur diversity, distribution and evolution in the Late Triassic.

Animals↗

PubMed1988

Concentration-affinity equivalence in gene regulation: convergence of genetic and environmental effects.

It is proposed that equivalent phenotypic effects can be obtained by either structural changes in macromolecules involved in gene regulation or changes in activity of the structurally unaltered macromolecules. This equivalence between changes in activity (concentration) and changes in structure can come into play within physiologically plausible limits and seems to represent an important interface between environment and genome--namely, between environmentally determined and genetically determined gene expression. The equivalence principle helps explain the appearance of phenocopies. It also points to a general pathway favorable to the occurrence, during evolution, of frequent episodes corresponding to Waddington's genetic assimilation and is likely to represent one component of the system responsible for the high frequency of recurrence of parallel evolution.

Biological Evolution↗

PubMed2005

The evolution of Titan's mid-latitude clouds.

Spectra from Cassini's Visual and Infrared Mapping Spectrometer reveal that the horizontal structure, height, and optical depth of Titan's clouds are highly dynamic. Vigorous cloud centers are seen to rise from the middle to the upper troposphere within 30 minutes and dissipate within the next hour. Their development indicates that Titan's clouds evolve convectively; dissipate through rain; and, over the next several hours, waft downwind to achieve their great longitude extents. These and other characteristics suggest that temperate clouds originate from circulation-induced convergence, in addition to a forcing at the surface associated with Saturn's tides, geology, and/or surface composition.

Atmosphere↗

PubMed1990

Development and evolution of the carotid circulation in geomyoid rodents in relationship to their craniomorphology.

The diversity in cranial morphology of living geomyoids, including pocket gophers (Thomomys), spiny pocket mice (Heteromys and Liomys), desert pocket mice (Chaetodipus and Perognathus), and kangaroo rats and mice (Dipodomys and Microdipodops) is accompanied by only a few differences in their cephalic arterial circulation. The principal difference is the origin of the pterygopalatine artery, which serves the orbit and rostrum. In dipodomyines and perognathines it originates as a stapedial branch of the internal carotid artery and passes through the middle ear en route to the braincase. In geomyines and heteromyines it originates as an internal maxillary branch of the external carotid artery and enters the braincase directly. Either geomyines and heteromyines are convergent in this respect, or the currently recognized family Heteromyidae is paraphyletic. The stapedial artery is the same size in early embryos of T. bottae and D. merriami, but in the former species it fails to grow and disappears in juveniles. Comparison of developmental series of D. merriami and T. bottae revealed that the decline of the artery in the latter species is preceded by a greater degree of arterial coarctation, or narrowing, as it passes though the developing stapes. The loss of the stapedial artery is correlated with an enlarged masseter profundus muscle in T. bottae and with an unusually small stapes in T. bottae, H. desmarestianus, and L. salvini. I hypothesize that the primitive condition for geomyoids is the presence of both stapedial and internal maxillary arteries, that the stapedial artery was lost in geomyines and heteromyines because of the constraint on its size posed by the stapes, and that the stapedial artery was retained in dipodomyines because enlargement of the stapes accompanied bullar inflation in these taxa and lifted the constraint on the size of the stapedial artery.

Animals↗

PubMed2006

Molecular phylogeny of New World Myotis (Chiroptera, Vespertilionidae) inferred from mitochondrial and nuclear DNA genes.

Recent studies have shown that species in the genus Myotis have evolved a number of convergent morphological traits, many of which are more related to their mode of food procurement than to their phylogeny. Surprisingly, the biogeographic origins of these species are a much better predictor of phylogenetic relationships, than their morphology. In particular, a monophyletic clade that includes all New World species was apparent, but only a third of the 38 species have been analysed. In order to better understand the evolution of this clade, we present phylogenetic reconstructions of 17 Nearctic and 13 Neotropical species of Myotis compared to a number of Old World congeners. These reconstructions are based on mitochondrial cytochrome b (1140 bp), and nuclear Rag 2 genes (1148 bp). Monophyly of the New World clade is strongly supported in all analyses. Two Palaearctic sister species, one from the west (M. brandtii) and one from the east (M. gracilis), are embedded within the New World clade, suggesting that they either moved across the Bering Strait, or that they descended from the same ancestor that reached the New World. An emerging feature of these phylogenetic reconstructions is that limited faunal exchanges have occurred, including between the North and South American continents, further emphasizing the importance of biogeography in the radiation of Myotis. A fossil-calibrated, relaxed molecular-clock model was used to estimate the divergence time of New World lineages to 12.2+/-2.0 MYA. Early diversification of New World Myotis coincides with the sharp global cooling of the Middle Miocene. Radiation of the temperate-adapted Myotis may have been triggered by these climatic changes. The relative paucity of species currently found in South America might result from a combination of factors including the early presence of competitors better adapted to tropical habitats.

Animals↗

PubMedDate not supplied

[Evolution of childhood hospitalization in Spain. Variation among autonomous communities].

BACKGROUND: To describe trends in children hospitalization in Spain during 1985-1994 and its variability among regions. METHODS: Description between 1985 and 1994, by autonomous regions, of the evolution in the rates of available beds, discharges, stays and visits and average length of stay, from data provided by the health care centres with inpatient statistics. RESULTS: The average length of stay decreased 23.9%, but there was a 4.5% increase in bed availability, a 39.5% increase in the discharges rate and 36.8% in the visits rate. Regions showed large differences in all indicators, that trends to converge in beds availability and discharges, but not in length of stay and visits rate. CONCLUSIONS: There has been an increase in hospital performance with strong variation among regions. Differences tends to reduce in some indicators but not in others.

Adolescent↗

PubMed2005

Ontogeny of additive and maternal genetic effects: lessons from domestic mammals.

Evolution of size and growth depends on heritable variation arising from additive and maternal genetic effects. Levels of heritable (and nonheritable) variation might change over ontogeny, increasing through "variance compounding" or decreasing through "compensatory growth." We test for these processes using a meta-analysis of age-specific weight traits in domestic ungulates. Generally, mean standardized variance components decrease with age, consistent with compensatory growth. Phenotypic convergence among adult sheep occurs through decreasing environmental and maternal genetic variation. Maternal variation similarly declines in cattle. Maternal genetic effects are thus reduced with age (both in absolute and relative terms). Significant trends in heritability (decreasing in cattle, increasing in sheep) result from declining maternal and environmental components rather than from changing additive variation. There was no evidence for increasing standardized variance components. Any compounding must therefore be masked by more important compensatory processes. While extrapolation of these patterns to processes in natural population is difficult, our results highlight the inadequacy of assuming constancy in genetic parameters over ontogeny. Negative covariance between direct and maternal genetic effects was common. Negative correlations with additive and maternal genetic variances indicate that antagonistic pleiotropy (between additive and maternal genetic effects) may maintain genetic variance and limit responses to selection.

Aging↗

PubMed1995

L1 (LINE-1) retrotransposable elements provide a "fossil" record of the phylogenetic history of murid rodents.

The single most difficult problem in phylogenetic analysis is deciding whether a shared taxonomic character is due to common ancestry or one that appeared independently due to convergence, parallelism, or reversion to an ancestral state. Mammalian L1 retrotransposons undergo periodic amplifications in which multiple copies of the elements are interspersed in the genome. Because these elements apparently are transmitted only by inheritance and are retained in the genome, a shared L1 amplification event can only be an inherited ancestral character. We propose that L1 amplification events can be an excellent tool for analyzing mammalian evolution and demonstrate here how we addressed several refractory problems in rodent systematics using L1 DNA as a taxonomic character.

Animals↗

PubMed2006

Evolution of a strategy for the synthesis of structurally complex batzelladine alkaloids. Enantioselective total synthesis of the proposed structure of batzelladine F and structural revision.

Stereoselective synthesis of octahydro-5,6,6a-triazaacenaphthalenes 29 and 34 having the anti-relationship of the angular hydrogens flanking the pyrrolidine nitrogen confirmed suspicions that the relative configuration of the left-hand tricyclic guanidine fragment of batzelladine F should be revised to have the syn relationship of these hydrogens. Several strategies were examined for coupling tricyclic guanidine fragments to prepare potential structures for batzelladine F. Eventually, a convergent synthesis strategy was devised, whose central step was a fragment-coupling tethered-Biginelli reaction (Scheme 17). Using this approach we synthesized four potential structures of batzelladine F, 35-38. None of these compounds, nor their enantiomers, were identical to natural batzelladine F. Reinvestigation of mass spectra of natural batzelladine F, and fragments 88 and 89 obtained upon saponification of batzelladine F, demonstrated that the originally proposed connectivity of this alkaloid was also incorrect. The revised connectivity, 90, of natural batzelladine F depicted in Scheme 21 is proposed.

Acenaphthenes↗

PubMedDate not supplied

Disk-covering, a fast-converging method for phylogenetic tree reconstruction.

The evolutionary history of a set of species is represented by a phylogenetic tree, which is a rooted, leaf-labeled tree, where internal nodes represent ancestral species and the leaves represent modern day species. Accurate (or even boundedly inaccurate) topology reconstructions of large and divergent trees from realistic length sequences have long been considered one of the major challenges in systematic biology. In this paper, we present a simple method, the Disk-Covering Method (DCM), which boosts the performance of base phylogenetic methods under various Markov models of evolution. We analyze the performance of DCM-boosted distance methods under the Jukes-Cantor Markov model of biomolecular sequence evolution, and prove that for almost all trees, polylogarithmic length sequences suffice for complete accuracy with high probability, while polynomial length sequences always suffice. We also provide an experimental study based upon simulating sequence evolution on model trees. This study confirms substantial reductions in error rates at realistic sequence lengths.

Algorithms↗

PubMed2004

Genetics and public health--evolution, or revolution?

During the 19th and early 20th century, public health and genetics shared common ground through similar approaches to health promotion in the population. By the mid-20th century there was a division between public health and genetics, with eugenicists estranged and clinical genetics focused on single gene disorders, usually only relevant to small numbers of people. Now through a common interest in the aetiology of complex diseases such as heart disease and cancer, there is a need for people working in public health and genetics to collaborate. This is not a comfortable convergence for many, particularly those in public health. Nine main concerns are reviewed: fear of eugenics; genetic reductionism; predictive power of genes; non-modifiable risk factors; rights of individuals compared with populations; resource allocation; commercial imperative; discrimination; and understanding and education. This paper aims to contribute to the thinking and discussion about an evolutionary, multidisciplinary approach to understanding, preventing, and treating complex diseases.

Attitude to Health↗

PubMed2006

Mitochondrial genome dynamics in plants and animals: convergent gene fusions of a MutS homologue.

Mitochondrial processes influence a broad spectrum of physiological and developmental events in higher eukaryotes, and their aberrant function can lead to several familiar disease phenotypes in mammals. In plants, mitochondrial genes directly influence pollen development and the occurrence of male sterility in natural plant populations. Likewise, in animal systems evidence accumulates to suggest important mitochondrial functions in spermatogenesis and reproduction. Here we present evidence for a convergent gene fusion involving a MutS-homologous gene functioning within the mitochondrion and designated Msh1. In only plants and soft corals, the MutS homologue has fused with a homing endonuclease sequence at the carboxy terminus of the protein. However, the endonuclease domains in the plants and the soft corals are members of different groups. In plants, Msh1 can influence mitochondrial genome organization and male sterility expression. Based on parallels in Msh1 gene structure shared by plants and corals, and their similarities in reproductive behavior, we postulate that this convergent gene fusion might have occurred in response to coincident adaptive pressures on reproduction.

Adenosine Triphosphatases↗