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PubMed1996

Hypothesis on a casual link between EMF and an evolutionary class of cancer and spontaneous abortion.

A biophysical theory is presented that supports a causal link between EMF exposures and the different biological endpoints of cancer and spontaneous abortion. The model for time-dependent instability of DNA specificity [Biochem. Genet. 32, 383 (1994)] is assumed to have been operational since DNA became selected as the molecular structure for the genome. Species were consequently required to adapt mechanisms to protect haploid gene pools from the continuous time-dependent accumulation of evolutionary base substitutions. To this end, conserved genetic domains containing mutation-intolerance thresholds are a result of natural selection operating on time-dependent base substitutions. "P53-type" genes are examples of such conserved domains with point mutation thresholds. When the oocyte is fertilized, conserved domains express wild type keto-amino genetic information. During subsequent development and growth, time-dependent evolution events populate G-C sites with enol-imine stationary states that can be transcribed and/or replicated to express transversion and transition mutations. As the level of evolution events would approach the intolerance threshold in the haploid genome, point mutation sensitive genes from conserved diploid domains, e.g. "p53-type" genes, would generate amino acid substituted proteins that have been evolutionarily selected to participate in species preservation by removing from the gene pool those haploid genomes containing advanced levels of mutation which, if propagated, would be inconsistent with survival. Consistent with the evolutionary origin of cancer hypothesis [Cancer Biochem. Biophys: 13, 147 (1993)], perturbations that would enhance rates of populating G-C sites with enol-imine states could accelerate point mutation "activation" of "p53-type" genes that could be manifested as premature cancer in living populations or expressed as spontaneous abortion in unborn populations. The evolution event "rate constant" is (gamma/h)2 where gamma is the quantum mechanical energy shift between G-C states. This expression implies that "additional" magnetic fields could increase rates of populating enol-imine states due to Lorentz force momentum transfer to metastable proton oscillators where induced electric fields and local currents would subject elevated energy proton oscillators to collisional de-exciatations which would increase the energy density of chemical bonds that support hydrogen bonds in DNA, thereby introducing larger energy shift values in (gamma/h)2. This hypothesis is explored for "additional" magnetic fields in the range of 0.15 to 0.01 gauss where the influence of magnetic enhancement energies on rates of populating enol-imine stationary states is evaluated, using Gurney and Condon tunneling time calculations for unperturbed and magnetically enhanced protons to escape metastable keto-amino energy wells. Model calculations are qualitative and are consistent with the experimentally testable hypothesis that "additional" magnetic fields could cause increased rates of accumulating evolutionary base substitutions, thereby increasing probabilities of activating "p53-type" genes which could cause increased incidence of spontaneous abortion in unborn populations and increased incidence of cancer in living populations.

Abortion, Spontaneous↗
PubMed1997

On the Evolution of Reality-Some Biological Prerequisites and Evolutionary Stages

The discussion of the evolutionary origins of consciousness has largely been concentrated to the human mind, and it is only in recent years that a comparative ethological view has come into play. Even here, a tendency has been to look mainly at the primates. There is a vast literature that discusses the differences between human consciousness and cognition, compared with that of the other primates, but much less attention has been given to the fact that evolutionary gaps-fulgurations, emergences, new systems-have occurred at many stages in the evolution of cognition. More especially, the complexity of rather simple cognitive systems in lower animals has been underestimated, as well as the necessary prerequisites for a cognition worthy of the name to exist. Of particular interest in the discussion has been the views from evolutionary epistemology and radical constructivism, since they support the ethologically founded view that mind representations do not depict reality, but are adaptations for a successful way of behaving in the physical world, that reality in this sense is in the mind, that there are many realities, varying for different species-rich or poor in complexity-but all of them basically of the same nature. Even such human achievements as mathematics or logic thus may be seen as specific cognitive adaptions in our species, not as independent aspects of the physical world. Copyright 1997 Academic Press Limited

Journal Article↗
PubMed1997

On the evolution of reality--some biological prerequisites and evolutionary stages.

The discussion of the evolutionary origins of consciousness has largely been concentrated to the human mind, and it is only in recent years that a comparative ethological view has come into play. Even here, a tendency has been to look mainly at the primates. There is a vast literature that discusses the differences between human consciousness and cognition, compared with that of the other primates, but much less attention has been given to the fact that evolutionary gaps-fulgurations, emergencies, new systems-have occurred at many stages in the evolution of cognition. More especially, the complexity of rather simple cognitive systems in lower animals has been underestimated, as well as the necessary prerequisites for a cognition worthy of the name to exist. Of particular interest in the discussion has been the views from evolutionary epistemology and radical constructivism, since they support the ethologically founded view that mind representations do not depict reality, but are adaptations for a successful way of behaving in the physical world, that reality in this sense is in the mind, that there are many realities, varying for different species-rich or poor in complexity-but all of them basically of the same nature. Even such human achievements as mathematics or logic may thus be seen as specific cognitive adaptions in our species, not as independent aspects of the physical world.

Animals↗
PubMed1998

[Evolutionary role of sex chromosomes (a new concept)].

Sex differentiation provides for testing evolutionary innovations in the male genome before they are transferred to the female genetic system. This is possible with dichronous (asynchronous) evolution, when evolution in males precedes that in females [3-7]. Hence, along with common autosomal genes for stable characters, exclusively male and exclusively female genes must exist. The male genes are already acquired by the male genome but are not yet transferred to the female one. The female genes are already lost by the male genome but still remain in the female genome. They constitute temporary evolutionary genotypic sexual dimorphism. Common genes cannot exhibit genotypic sexual dimorphism; they show only constant phenotypic hormonal sexual dimorphism. On the basis of the interpretation of genotypic sexual dimorphism as a consequence of sex dichronism, the evolutionary role of sex chromatins is clarified and a new concept for them is suggested. According to this concept, the Y chromosome is the "conductor" of ecological information into the genome, the "place of birth" and testing of new genes, the accelerator and regulator of genotypic sexual dimorphism. By contrast, the X chromosome of the heterogametic sex provides the transportation of new genes from the Y chromosome to autosomes. This chromosome stabilizes, relaxes, and suppresses genotypic sexual dimorphism and accumulates genes that will be eliminated. This concept sheds light on many problems: the chromosomal localization of genes and their transfer to other chromosomes, the inactivation of chromosomes, mobile genes, mutation bursts, insertional mutagenesis, the association of the Y chromosome with stress, retroviruses, etc. In particular, it explains why genes "jump," why transpositions of mobile elements depend on ecological stress, why different genes mutate simultaneously, etc.

Biological Evolution↗
PubMed2026

Divergent evolutionary strategies in spider venoms: A comparative proteomic profiling of four sympatric species from Yunnan.

Spider venoms comprise complex cocktails of bioactive molecules evolved for predation and defense, representing a valuable resource for biological research and pharmaceutical discovery. In this study, we performed a systematic analysis of venom gland extracts from four common spider species indigenous to Yunnan, China: Agelena limbata, Hippasa lycosina, Lycosa grahami, and Sinopoda pengi. Using an integrated transcriptomic and proteomic targeted profiling approach, we successfully annotated 141 distinct toxins. Comparative analysis revealed significant interspecific heterogeneity, suggesting distinct evolutionary trajectories and "weapon system economics." Both A. limbata and L. grahami exhibited a "peptide-dominant" profile anchored by neurotoxic peptides and isomerases, optimized for rapid chemical paralysis. In contrast, S. pengi displayed a distinct "protein-dominant" signature enriched with high-molecular-weight enzymes and CAP superfamily proteins, likely functioning to facilitate tissue degradation and toxin diffusion. Occupying an intermediate position, H. lycosina demonstrated a hybrid composition. These findings suggest that although these species share the same geographical range, their venom systems have undergone divergent evolutionary adaptations driven by specific ecological niches and hunting strategies. This study represents the first systematic proteomic characterization of these venom components, providing a valuable reservoir of molecular candidates while highlighting the bioinformatic nuances of analyzing whole-gland homogenates.

Animals↗
PubMed2002

The Radiata and the evolutionary origins of the bilaterian body plan.

The apparent conservation of cellular and molecular developmental mechanisms observed in a handful of bilaterian metazoans has spawned a "race" to reconstruct the bilaterian ancestor. Knowledge of this ancestor would permit us to reconstruct the evolutionary changes that have occurred along specific bilaterian lineages. However, comparisons among extant bilaterians provide an unnecessarily limited view of the ancestral bilaterian. Since the original bilaterians are believed by many to be derived from a radially symmetrical ancestor, additional evidence might be obtained by examining present-day radially symmetrical animals. We briefly review pertinent features of the body plans of the extant radial eumetazoan phyla, the Cnidaria, and Ctenophora, in the context of revealing potential evolutionary links to the bilaterians.

Animals↗
PubMed2005

Evolutionary analysis of the well characterized endo16 promoter reveals substantial variation within functional sites.

The evolutionary mechanisms that operate on genetic variation within transcriptional regulatory sequences are not well understood. We present here an evolutionary analysis of an exceptionally well characterized cis-regulatory region, the endo16 promoter of the purple sea urchin. Segregating variation reveals striking differences in the intensity of negative selection among regulatory modules, reflecting their distinct functional roles. Surprisingly, transcription-factor-binding sites are as polymorphic and as likely to contain fixed differences as flanking nucleotides. Whereas nucleotides in protein-binding sites in the most proximal regulatory module exhibit reduced variation, those in other modules tend to be more polymorphic than putatively nonfunctional nucleotides. Two unrelated large insertions at the same position within the promoter are segregating at low frequencies; one is a strong ectodermal repressor that contains 16 verified transcription-factor-binding sites. These results demonstrate that a simple relationship between conservation and function does not exist within this cis-regulatory region and highlight significant population heterogeneity in the fine structure of a well understood promoter.

Animals↗
PubMed2000

Evolutionary complementation for polymerase II CTD function.

The C-terminal domain (CTD) of the largest subunit (RPB1) of eukaryotic RNA polymerase II is essential for pol II function and has been shown to play a number of important roles in the mRNA transcription cycle. The CTD is composed of a tandemly repeated heptapeptide that is conserved in yeast, animals, plants and several protistan organisms. Some eukaryotes, however, have what appear to be degenerate or deviant CTD regions, and others have no CTD at all. The functional and evolutionary implications of this variation among RPB1 C-termini is largely unexplored. We have transformed yeast cells with a construct consisting of the yeast RPB1 gene with 25 heptads from the primitive protist Mastigamoeba invertens in place of the wild-type CTD. The Mastigamoeba heptads differ from the canonical CTD by the invariable presence of alanines in place of threonines at position 4, and in place of serines at position 7 of each heptad. Despite this double substitution, mutants are viable even under conditions of temperature and nutrient stress. These results provide new insights into the relative functional importance of several of the conserved CTD residues, and indicate that in vivo expression of evolutionary variants in yeast can provide important clues for understanding the origin, evolution and function of the pol II CTD.

Amoeba↗
PubMed1999

Bi-penta-bi-decaradial symmetry: A review of evolutionary and developmental trends in holothuroidea (echinodermata)

Holothuroidea, comprising the sea cucumbers, is the least studied class of extant echinoderms, yet this group possesses a wealth of features of potential interest to developmental and evolutionary biologists. Holothuroids include the most morphologically derived echinoderms, including pelagic species and spheroid, plated taxa with mouth and anus adjacent at the end of a long, flexible stalk. To begin investigating this diversity of body form, we first estimated evolutionary relationships in the class Holothuroidea based on maximum parsimony analyses of 1,075 nt of the nuclear small subunit rDNA (for six species in four orders) and on 52 informative morphological characters (for the 25 extant families). Both the morphological and molecular evidence suggests almost an inversion of the prevailing higher level classification. Character-state optimizations indicated that pronounced adult bilateral symmetry evolved three times. In one group even a regain of secondary radial symmetry is found. Respiratory trees, structures unique to holothuroids, are a relatively late innovation, are ectodermally derived, and are bilaterally symmetric, supporting the possibility that the secondary gain of bilateral symmetry in holothuroids is ectodermally derived analogous to, say, the derivation of vertebrate limb dorso-ventral axis. The test of imbricating plates found in 10% of living holothuroids is apparently not homologous with that of other heavily armored echinoderms, evolving much later and at least twice. Indirectly developing larvae, auriculariae, occur in two evolutionarily disparate clades and unlike echinoids comprise a minority of clades. We suggest that this implies the parallel convergent evolution of this larval type or, more speculatively, some form of retention of developmental constraints. J. Exp. Zool. (Mol. Dev. Evol.) 285:93-103, 1999. Copyright 1999 Wiley-Liss, Inc.

Journal Article↗
PubMed1998

Evolutionary and ecological implications of primate seed dispersal.

In this paper, we evaluate patterns of fruit eating and seed dispersal in monkeys and apes and draw an important distinction between 1) the ecological consequences of primates as seed dispersers and 2) the evolutionary implications of primates on the seed and fruit traits of the plant species they exploit. In many forest communities, primates act as both seed predators and seed dispersers and are likely to have an important ecological impact on patterns of forest regeneration and tree species diversity. Evidence from Kibale National Park, Uganda, and Manu National Park, Peru, as well as several other South American sites indicates that monkeys and apes display a wide range of fruit-processing behaviors, including spitting seeds, dropping seeds, masticating seeds, and swallowing seeds. Differences in consumer body size, diet, ranging patterns, and oral and digestive morphology result in different patterns in the distance and distribution of seeds from the parent plant. In the case of South American monkeys, for example, despite their relatively small body size, platyrrhines were found to exploit larger fruits and swallow larger seeds on average than did Old World monkeys and apes of the Kibale forest. We found little evidence to support the existence of a coevolutionary relationship between a single or set of primate dispersers and the particular plant species they disperse. This is due to variability in the manner in which monkeys and apes select fruits and treat seeds, the fact that many species of primates and nonprimates exploit and disperse the same fruit species, and the fact that extremely high levels of postdispersal seed, seedling, and sapling mortality serve to dilute the influence that any primate species may have on the recruitment of the next generation of adult trees. It is apparent that many primate lineages exhibit dental, digestive, and/or sensory adaptations that aid in the exploitation of particular food types and that many lineages of flowering plants have evolved characteristics of fruits and seeds that facilitate seed dispersal. However, in light of currently available data, we argue that these represent evolutionary rather than more strictly defined coevolutionary relationships.

Animals↗
PubMed2000

Hepatitis B virus infection among residents of a nursing home for the elderly: seroepidemiological study and molecular evolutionary analysis.

A seroepidemiological study of HBV infection was carried out to investigate the seroprevalence of hepatitis B surface antigen (HBsAg) and the transmission routes of hepatitis B virus (HBV) infection among residents of a nursing home for the elderly. HBV serum markers were examined in 119 residents and 71 healthcare workers in the institution, as also in 1330 healthy subjects from the same geographical area, as the control group. HBsAg was detected in 6 (5%), 0 and 20 (1.5%) residents, healthcare workers and healthy subjects, respectively. Four residents (A-D) who had HBV-DNA in the serum were studied by molecular evolutionary analysis. The strains derived from residents A, B and D were clustered together within a close range of evolutionary distances. Residents B and D, who were not positive for HBsAg at the time of admission to the institution, subsequently became HBsAg-positive asymptomatic carriers. These results suggested intrainstitutional transmission of HBV in the nursing home for the elderly, and confirmed that the source of transmission of HBV to residents B and D was resident A who was positive for HBsAg. Residents in a nursing home for the elderly should be considered as being a high-risk group for HBV infection, and vaccination against HBV of these groups is recommended.

Aged↗
PubMed2000

The duplication of an eight-residue helical stretch in Staphylococcal nuclease is not helical: a model for evolutionary change.

A common method of evolutionary change is gene duplication, followed by other events that lead to new function, decoration of folds, oligomerization, or other changes. As part of a study on the potential for evolutionary change created by duplicated sequences, we have carried out a crystallographic study on a mutant of Staphylococcal nuclease in which residues 55-62 have been duplicated in a wild-type variant termed PHS. In the parental protein (PHS) these residues form the first two turns of a helix running from residue 54 to 68 (hereafter designated as helix I). The crystal structure of the mutant is very similar to that of the parental, with helix I being unaltered. The duplicated residues are accommodated by expanding an existing loop N-terminal to helix I. In addition, circular dichroism (CD) studies have been carried out on a parental peptide containing helix I with six flanking residues at each terminus (residues 48-74) and on the same peptide expanded by the duplication, as a function of 2,2,2-trifluoroethanol (TFE) concentration. Each peptide possesses only modest helical propensity in solution. Our data, which is different from what was observed in T4 lysozyme, show that the conformation of the duplicated sequence is determined by a balance of sequential and longer-range effects. Thus duplicating sequence need not mean duplicating structure. Proteins 2000;40:465-472.

Algorithms↗
PubMed2000

How genomic and developmental dynamics affect evolutionary processes.

Evolutionary genetics is concerned with natural selection and neutral drift, to the virtual exclusion of almost everything else. In its current focus on DNA variation, it reduces phenotypes to symbols. Varying phenotypes, however, are the units of evolution, and, if we want a comprehensive theory of evolution, we need to consider both the internal and external evolutionary forces that shape the development of phenotypes. Genetic systems are redundant, modular and subject to a variety of genomic mechanisms of "turnover" (transposition, gene conversion, unequal crossingover, slippage and so on). As such the construction and spread of novel combinations of modules by turnover, in particular within gene promoters, contributes significantly to the evolution of phenotypes. Furthermore, redundancy, turnover and modularity lead to ever more complex networks of genetic interactions and ever more functions for a given module. The significant interaction between genomic turnover and natural selection leads to a molecular coevolution between interacting modules and hence facilitates the establishment of biological novelties.

Animals↗
PubMed1996

Evolutionary adaptationism: another biological approach to criminal and antisocial behaviour.

Although in a sense "genetic', the conceptual framework of evolutionary psychology, behavioural ecology and sociobiology is distinct from that of behaviour genetics. Considerable confusion has resulted from failures to recognize the distinctions. These disciplines are primarily concerned with the characterization of evolved adaptations, which are usually species-typical and environmentally contingent, so theory and research in these fields mainly concerns environmental rather than genetic sources of behavioural variation. Heritable behavioural variation is in general neither predicted by nor supportive of adaptationist theories. One might even say that substantial heritability of an apparently consequential attribute is a datum that challenges the tenets of adaptationism. Behaviour genetics and evolutionary adaptationism have had only limited mutual influence, but increasing knowledge of the processes by which genotypes affect behavioural phenotypes should facilitate development of a more synthetic approach.

Adaptation, Psychological↗
PubMed1997

Evolutionary conflicts and adapted psychologies.

Animal information processing and decision making are often considered to be adaptations that allow individuals to behave optimally under particular ecological conditions. Numerous examples demonstrate how cues from the biotic and abiotic environments affect the ways in which animals process information and make decisions. Information gained from interactions with living organisms is the most complex because individuals have to respond to heterospecifics or conspecifics which may decide on what to do depending on the behaviour of a focal individual. Evolutionary conflicts of interest include: (i) interactions between hosts and parasites, predators and prey, and between competitors; (ii) sperm competition interactions between females, male mates and male non-mates, and (iii) interactions between mate-searching females and their potential mates. Brains may evolve particularly rapidly under the influence of evolutionary conflicts and they may enhance the importance of adapted psychologies in these contexts.

Adaptation, Psychological↗
PubMed1999

Larval homologies and radical evolutionary changes in early development.

Larval forms are highly conserved in evolution, and phylogeneticists have used shared larval features to link disparate phyla. Despite long-term conservation, early development has in some cases evolved radically. Analysis of evolutionary change depends on identification of homologues, and this concept of descent with modification applies to embryo cells and territories as well. Difficulties arise because evolutionary changes in development can obscure homologies. Even more difficult, threshold effects can yield changes in process whereby apparently homologous features can arise from new precursors or pathways. We have observed phenomena of this type in closely related sea urchins that differ in developmental mode. A species developing via a complex feeding larva and its congener, which develops directly, have different embryonic cell lineages and divergent patterns of early development, but converge on the adult sea urchin body plan. Despite differences in embryonic developmental pathways, conserved gene expression territories are evident, as are territories whose homologies are in doubt. The highly derived development of the direct developer evidently arises from an interplay of novel organization of the egg, loss of expression of regulatory gene involved in production of feeding larval features, and changes in site and timing of expression of a number of genes.

Adaptation, Biological↗
PubMed1999

Evolutionary aspects of plant-carnivore interactions.

Plants can respond actively to damage by herbivores. In addition to a mode of defence that is directly aimed at the herbivore itself, plants can emit volatiles that attract carnivores, i.e. the enemies of their enemies. Knowledge of the mechanisms underlying the induction of these herbivore-induced plant volatiles and of the responses of the carnivores is progressing rapidly. Inferences on the initial causes of evolution of herbivore-induced plant volatiles remain conjectural. However, once plant-carnivore interactions have evolved to the net benefit of both participants this mutualism is expected to have evolutionary and ecological consequences for the three trophic levels involved. When plant selection and foraging behaviour of natural enemies is linked to plant fitness this can influence different aspects of the plant defence strategy. The way carnivores perceive and process plant information may influence the evolution of the plant signal (i.e. quantitative and qualitative composition of the odour blend in response to herbivore damage). Vice versa, the signal-to-noise ratio of the information may influence the way carnivores respond to plant cues (innately or through learning). Selection will act on herbivores to disconnect the plant-carnivore link, for example by boycotting the informational value of herbivore-induced synomones. Through plant selection and feeding behaviour herbivores can influence their chance of being found by carnivores. Hence, responses of carnivores to plant cues can influence the evolution of food-plant use by herbivores. The conspiracy between plants and carnivores is at the heart of evolutionary ecology, and wide open for experimental and theoretical investigations.

Animals↗
PubMedDate not supplied

Issues in evolutionary medicine.

This paper illustrates the utility of applying evolutionary thought to medical issues with three examples: selection arenas, aging, and tradeoffs. First, the human female reproductive tract functions as a selection arena at two levels: in the ovaries, where atresia reduces the number of oocytes by more than 99.99% before any are ovulated, and in the uterus, where early embryos homozygous for immune genes are spontaneously aborted. These selective filters early in life have implications both for eugenics and for the anti-abortion movement. Second, the evolutionary theory of aging predicts that intrinsic mortality should reflect extrinsic mortality: if life for adults is risky, then it does not pay to invest in maintenance at the expense of reproduction. This idea is well confirmed, at least in populations where density effects are not important. While only organisms that reproduce asymmetrically should age, even bacteria reproduce asymmetrically, and they do age, suggesting that all organisms reproduce asymmetrically and therefore age. Third, tradeoffs are central to theories of phenotypic design, but the mechanisms that cause them remain obscure. A method is suggested to get at the mechanisms of tradeoffs by examining conflicts among functions over gene expression. It could be applied in humans to the tradeoff between reproductive performance and disease resistance.

Aging↗