Originating in the work of Ernst Haeckel and Wilhelm Preyer, and advanced by a Prussian embryologist, Wilhelm Roux, the idea of struggle for existence between body parts helped to establish a framework, in which population cell dynamics rather than a predefined harmony guides adaptive changes in an organism. Intended to provide a causal-mechanical view of functional adjustments in body parts, this framework was also embraced later by early pioneers of immunology to address the question of vaccine effectiveness and pathogen resistance. (...) As an extension of these early efforts, Elie Metchnikoff established an evolutionary vision of immunity, development, pathology, and senescence, in which phagocyte-driven selection and struggle promote adaptive changes in an organism. Despite its promising start, the idea of somatic evolution lost its appeal at the turn of the twentieth century giving way to a vision, in which an organism operates as a genetically uniform, harmonious entity. (shrink)

The widespread potential for somatic fusion among different conspecific multicellular individuals suggests that such fusion is adaptive. However, because recognition of non‐kin (allorecognition) usually leads to a rejection response, successful somatic fusion is limited to close kin. This is consistent with kin‐selection theory, which predicts that the potential cost of fusion and the potential for somatic parasitism decrease with increasing relatedness. Paradoxically, however, Crozier1 found that, in the short term, positive‐frequency‐dependent selection eliminates the required genetic polymorphism at (...) allorecognition loci. The ‘Crozier paradox’ may be solved if allorecognition is based on extrinsically balanced polymorphisms, for example at immune loci. Alternatively, the assumption of most models that self fusion is mutually beneficial is wrong. If fusion is on average harmful, selection will promote unconditional rejection. However, we propose that fusion within individuals is beneficial, selecting for the ability to fuse, but fusion between individuals on average costly, selecting for non‐self recognition (rather than non‐kin recognition). We discuss experimental data on fungi that are consistent with this hypothesis. BioEssays 30:1193–1203, 2008. © 2008 Wiley Periodicals, Inc. (shrink)

An understanding of the factors behind the evolution of multicellularity is one of today’s frontiers in evolutionary biology. This is because multicellular organisms are made of one subset of cells with the capacity to transmit genes to the next generation and another subset responsible for maintaining the functionality of the organism, but incapable of transmitting genes to the next generation. The question arises: why do somatic cells sacrifice their lives for the sake of germline cells? How is germ/soma (...) separation maintained? One conventional answer refers to inclusive fitness theory, according to which somatic cells sacrifice themselves altruistically, because in so doing they enhance the transmission of their genes by virtue of their genetic relatedness to germline cells. In the present article we will argue that this explanation ignores the key role of policing mechanisms in maintaining the germ/soma divide. Based on the pervasiveness of the latter, we argue that the role of altruistic mechanisms in the evolution of multicellularity is limited and that our understanding of this evolution must be enriched through the consideration of coercion mechanisms. (shrink)

Most eukaryotes possess many copies of rDNA. Organismal selection alone cannot maintain rRNA function because the effects of mutations in one rDNA are diluted by the presence of many other rDNAs. rRNA quality is maintained by processes that increase homogeneity of rRNA within, and heterogeneity among, germ cells thereby increasing the effectiveness of cellular selection on ribosomal function. A successful rDNA repeat will possess adaptations for spreading within tandem arrays by intranuclear selection. These adaptations reside in the non‐coding regions of (...) rDNA. Single‐copy genes are predicted to manage processes of intranuclear and cellular selection in the germline to maintain the quality of rRNA expressed in somatic cells of future generations. (shrink)

Several DNA-damage detection and repair mechanisms have evolved to repair double-strand breaks induced by mutagens. Later in evolutionary history, DNA single- and double-strand cuts made possible immune diversity by V(D)J recombination and recombination at meiosis. Such cuts are induced endogenously and are highly regulated and controlled. In meiosis, DNA cuts are essential for the initiation of homologous recombination, and for the formation of joint molecule and crossovers. Many proteins that function during somatic DNA-damage detection and repair are also active (...) during homologous recombination. However, their meiotic functions may be altered from their somatic roles through localization, posttranslational modifications and/or interactions with meiosis-specific proteins. Presumably, somatic repair functions and meiotic recombination diverged during evolution, resulting in adaptations specific to sexual reproduction. BioEssays 27:795–808, 2005. © 2005 Wiley Periodicals, Inc. (shrink)

The extent to which normal (nonmalignant) cells of the body can evolve through mutation and selection during the lifetime of the organism has been a major unresolved issue in evolutionary and developmental studies. On the one hand, stable multicellular individuality seems to depend on genetic homogeneity and suppression of evolutionary conflicts at the cellular level. On the other hand, the example of clonal selection of lymphocytes indicates that certain forms of somatic mutation and selection are concordant with the organism-level (...) fitness. Recent DNA sequencing and tissue physiology studies suggest that in addition to adaptive immune cells also neurons, epithelial cells, epidermal cells, hematopoietic stem cells and functional cells in solid bodily organs are subject to evolutionary forces during the lifetime of an organism. Here we refer to these recent studies and suggest that the expanding list of somatically evolving cells modifies idealized views of biological individuals as radically different from collectives. (shrink)

The authors propose that many morbidities higher in women than men are adaptations protecting survival, selected because survival has been especially crucial to mothers' reproductive success. Following their lead, I pursue variation in tradeoffs between reproduction and survival recognized by Darwin that were likely central to the evolution of many traits that distinguish us from our great ape cousins.

The argument is put forward that genetic mutations are viable then only, when the changed pattern of growth and/or metabolism is accommodated by the taxon-specific biochemistry of the organisms, i.e. by adaptive, somatic/physiological plasticity. The range of somatic plasticity under changing environmental conditions, therefore, has a certain predictive value for the kind of mutations that are likely to be viable.

Purpose. The main purpose of the article is the analysis of the phenomenon and manifestations of the somatic transformations in the context of anthropo-technological evolution at the beginning of the XXI century. Theoretical basis. The author determines the understanding of the concept "somatic transformations" in the frames of anthropotechnogynesis is possible only on the base of integrative approach and combination of post-non-classical scientific paradigm methodology, theory of the technological development, ideas of trans-humanism, informative society concepts, and net (...) technologies influence on the identity of the human being with robots in the sphere of bioethics and nanoethics, the ethics of new technologies and legal documents which are regulating the processes of technotransformation of the human being. Originality. The author has proved on the example of analysis of the somatic transformations own psychosomatics as he solves some important global in the context of anthropotechnogynesis that a person with help of technological enlargement of and branch problems, so he is trapped of alienation in the very crucial stage, loses the identity and crashes the corporeality in his self. Conclusions. As evidenced by the given analysis, at the modern stage the anthropotechnogynesis is followed by the large-scale quantitative and qualitative somatic transformations based on NBIC-convergence, as a result, a new anthropological subspecies – Homo technologicus appears. All these transformations are a regular stage of evolution, which confirms the thesis of the essential and functional connection of technology with the human body, which are in a relationship of "mutual provocation". In the base of the paradigmatic ontological and anthropological shift which has been on the modern stage, lies the idea of continuity of anthropotechnological co-evolution of the human body and its environment which projects itself in psychosomatic human structure, making a transformation program for better adaptation in technonanobeing. The convergence of human life and techno-existence is a platform for somatic transformations. They are divided into two main groups: intra-structural, substantial, related to techno-modification of the human body directly through biotechnology and genetic engineering, cyborgization, xenotransplantation, Hi-Hume connection with Hi-Tech and others, and external-contextual, when under the influence of pancommunication and hybridization the environment is increasingly mentalized and somatized, and modern technologies are gradually transformed into the social body of man. (shrink)

This research note challenges the idea that Random Somatic Mutations are entirely random, highlighting their non-equiprobable nature and their influence on evolution, involution, or indeterminacy. It recalls the Neutrosophic Theory of Evolution, extending Darwin’s theory, and emphasizes the importance of distinguishing between different senses of ‘random mutation’ in evolutionary theory.

Clonal disease is often regarded as almost synonymous with cancer. However, it is becoming increasingly clear that our bodies harbor numerous mutant clones that are not tumors, and mostly give rise to no disease at all. Here we discuss three somatic mutations arising within the hematopoietic system: BCR‐ABL, characteristic of chronic myeloid leukemia; mutations of the PIG‐A gene, characteristic of paroxysmal nocturnal hemoglobinuria; the V617F mutation in the JAK2 gene, characteristic of myeloproliferative diseases. The population frequencies of these three (...) blood disorders fit well with a hierarchical model of hematopoiesis. The fate of any mutant clone will depend on the target cell and on the fitness advantage, if any, that the mutation confers on the cell. In general, we can expect that only a mutation in a hematopoietic stem cell will give long‐term disease; the same mutation taking place in a cell located more downstream may produce just a ripple in the hematopoietic ocean. (shrink)

Cancer is most commonly viewed as resulting from somatic mutations enhancing proliferation and invasion. Some hypotheses further propose that these new capacities reveal a breakdown of multicellularity allowing cancer cells to escape proliferation and cooperation control mechanisms that were implemented during evolution of multicellularity. Here we critically review one such hypothesis, named “atavism,” which puts forward the idea that cancer results from the re‐expression of normally repressed genes forming a program, or toolbox, inherited from unicellular or simple multicellular (...) ancestors. This hypothesis places cancer in an interesting evolutionary perspective that has not been widely explored and deserves attention. Thinking about cancer within an evolutionary framework, especially the major transitions to multicellularity, offers particularly promising perspectives. It is therefore of the utmost important to analyze why one approach that tries to achieve this aim, the atavism hypothesis, has not so far emerged as a major theory on cancer. We outline the features of the atavism hypothesis that, would benefit from clarification and, if possible, unification. (shrink)

Mitochondria exist in large numbers per cell. Therefore, the strength of natural selection on individual mtDNAs for their contribution to cellular fitness is weak whereas the strength of selection in favor of mtDNAs that increase their own replication without regard for cellular functions is strong. This problem has been solved for most mitochondrial genes by their transfer to the nucleus but a few critical genes remain encoded by mtDNA. Organisms manage the evolution of mtDNA to prevent mutational decay of (...) essential services mitochondria provide to their hosts. Bottlenecks of mitochondrial numbers in female germlines increase the homogeneity of mtDNAs within cells and allow intraorganismal selection to eliminate cells with low quality mitochondria. Mechanisms of intracellular “quality control” allow direct selection on the competence of individual mtDNAs. These processes maintain the integrity of mtDNAs within the germline but are inadequate to indefinitely maintain mitochondrial function in somatic cells. (shrink)

If all origins of life or of any new grade, level, or major transition as such begin with “competitive development”—with juveniles rather than adults, and multiple individuals rather than a single one—then the evolution of progeneration and of replication always requires an explanation. This article proposes that principles of evolutionary ecology such as density-dependence can be used to explain three kinds of developmental repetitions, viz., sequences of inductive and niche-constructing interactions between the ecological environment and population members, which take (...) place in such a way that the sequence is repeated: individual or somatic repetitions, discussed in Section 1, demographic or progenerative repetitions , discussed in Section 2, and replicative repetitions , discussed in Section 3. This results in a statement of the evolutionary process that includes rather than excludes development and ecology, but one which requires some additions to Van Valen’s aphorism that evolution is the control of development by ecology. (shrink)

Sexual eukaryotic organisms are characterized by an alternation between haploid and diploid phases. In vascular plants and animals, somatic growth and development occur primarily in the diploid phase, with the haploid phase reduced to the gametic cells. In many other eukaryotes, however, growth and development occur in both phases, with substantial variability among organisms in the length of each phase of the life cycle. A number of theoretical models and experimental studies have shed light on factors that may influence (...) life cycle evolution, yet we remain far from a complete understanding of the diversity of life cycles observed in nature. In this paper we review the current state of knowledge in this field, and touch upon the many questions that remain unanswered. BioEssays 20:453–462, 1998. © 1998 John Wiley & Sons, Inc. (shrink)

The paper continues the model I began in a previous issue of Sophia . It is argued that the predominance of purely ascending or ‘top down’ forms of spirituality which stemmed largely from the axial period and have been carried forward into modern, transpersonal theories of evolutionary spirituality is a mistake and that there exists a lost or largely ignored form of spirituality—which I name somatic—which was the predominant domain of early Neolithic and Palaeolithic experience. Aspects of what I (...) call somatic mystical experiences have certainly been acknowledged at times to a limited degree, though they have rarely been fully explored, and have usually been considered as basic to other kinds of mystical experience, rather than fully developed forms in their own right. This article offers a fuller exploration and places such states more accurately within a detailed developmental framework than has previously been the case. Other issues relating to the horizon model across the two papers are also expanded. (shrink)

A simple model, illustrating the transition from a population of free swimming, solitary cells to one consisting of small colonies serves as a basis to discuss the evolution of the cooperative group. The transition is the result of a mutation of the dynamics of cell division, delayed cell separation leads to colonies of four cells. With this mutation cooperative features appear, such as synchronised cell divisions within colonies and coordinated flagellar function which enables the colony to swim in definite (...) directions. The selective advantages under given, environmental conditions are defined and the periods necessary for complete allelic replacement in small populations are calculated for asexual and sexual reproduction. The assumption of a steady-state population during allelic substitution is critically considered, particularly under conditions of competition. It is shown that density-dependent population control must operate in the process of selection. Sexual reproduction slows down the rate of selection even though all cells dre haploid. This phenomenon can be explained in general terms of `organizational dominance', where individual units coordinate the function of their neighbours which may be of a different allelotype.Cooperativity is pointed out as an a priori systemic feature which resides in the sub-units of systems, group formation and coordination appears thus as an almost inevitable event. A particular type of system described as ‘closed cycle of positive fitness interaction’ is discussed in more detail. It has the remarkable feature that its members cannot compete with each other; selection takes place between whole cycles .Gonium has a wide spectrum of `somatic plasticity' which enables it to assume various colonial configurations depending on physiological and environmental conditions. This feature can be explained as the result of dynamic flexibilities on the macro-molecular level. The particular relationship between the vast, molecular complexity and the relative simple dynamics of the cell cycle must lead eventually to the genetic fixation of an environmentally induced phenotype. (shrink)

An alternative antigen receptor, named the variable lymphocyte receptor (VLR), was first identified in lampreys in 2004. Since then, the mechanism of VLR diversification via somatic gene assembly and the function of VLR‐expressing lymphocytes have been the subject of much research. VLRs comprise leucine‐rich repeat (LRR) motifs and are found only in the most phylogenetically distant vertebrates from mammals, lampreys, and hagfish. Previous reports showed that VLRA and VLRB are reciprocally expressed by lymphocytes that resemble T‐ and B cells; (...) however, more recent reports show that another VLR, VLRC, is expressed on a third lymphocyte lineage, which may be equivalent to γδ T cells. The existence of three major lymphocyte lineages – one B‐cell‐like and two T‐cell‐like – and their development in lampreys, parallels the mammalian adaptive immune system. This suggests that these three cell lineages were present in the common vertebrate ancestor approximately 500 million years ago. (shrink)

In 1920, Eugen Steinach and Paul Kammerer reported experiments showing that exposure to high temperatures altered the structure of the gonad and produced hyper-sexuality in "heat rats," presumably as a result of the increased production of sex hormones. Using Steinach's evidence that the gonad is a double gland with distinct sexual and generative functions, they used their findings to explain "racial" differences in the sexuality of indigenous tropical peoples and Europeans. The authors also reported that heat induced anatomical changes in (...) the interstitial cells of the gonad were inherited by the heat rats' descendants. Kammerer used this finding to link endocrinology to his long-standing interest in the inheritance of acquired characteristics. The heat rats supported his hypothesis that the interstitial cells of the double gland were the mechanism of somatic induction in the inheritance of acquired characteristics. The Steinach-Kammerer collaboration, Kammerer's use of Steinach's "puberty gland" to explain somatic induction, and his endocrine analysis of symbiosis reveal Paul Kammerer's late career attempt to integrate endocrinology and genetics with the political ideals of Austrian socialism. With them he developed a bioethics that challenged the growing reliance on race in eugenics and instead promoted cooperation over competition in evolution. I relate his attempt to the controversies surrounding the interstitial cells, to the status of extra-nuclear theories of heredity, and to Kammerer's commitment to Austromarxist social reforms during the interwar period. (shrink)

In the eukaryotic cell, DNA compaction is achieved through its interaction with histones, constituting a nucleoprotein complex called chromatin. During metazoan evolution, the different structural and functional constraints imposed on the somatic and germinal cell lines led to a unique process of specialization of the sperm nuclear basic proteins (SNBPs) associated with chromatin in male germ cells. SNBPs encompass a heterogeneous group of proteins which, since their discovery in the nineteenth century, have been studied extensively in different organisms. (...) However, the origin and controversial mechanisms driving the evolution of this group of proteins has only recently started to be understood. Here, we analyze in detail the histone hypothesis for the vertical parallel evolution of SNBPs, involving a “vertical” transition from a histone to a protamine‐like and finally protamine types (H → PL → P), the last one of which is present in the sperm of organisms at the uppermost tips of the phylogenetic tree. In particular, the common ancestry shared by the protamine‐like (PL)‐ and protamine (P)‐types with histone H1 is discussed within the context of the diverse structural and functional constraints acting upon these proteins during bilaterian evolution. (shrink)

Within a physicalist-mechanistic worldview, in which we cannot be more than intelligent, self-reproducing biomachines or biobots, fundamentals of a new approach to the science of human self-explanation are outlined. Some a priori logical necessities, or determinants, of any biobot’s control system design are recognized. Evolution had to satisfy them, but neuroscience and cognitive science so far do not clearly see these basics. It is concluded that the old part of the brain still contains the genetically fixed drives, responses, and (...) the physiological control. Here is the seat of an ancient somatic self that is not intelligent but is still the active center of our life. The neocortex has evolved to serve the somatic self with intelligence by individually building a virtual model of the external material and social world. This model is used by the somatic self to “pre-play” intended actions and responses to see whether they would satisfy its needs. This schema of global brain function provides the neurological foundation for the ego-id dichotomy in analytic psychology, as well as some critique of it. Following the groundbreaking experiments by Benjamin Libet and John-Dylan Haynes et al. , consciousness is taken as a “theater” that presents what the neural networks already have worked out, and freedom of the will is limited. The explosive growth of culture and civilization began when neocortical power exceeded a certain threshold. This can be taken as a quasi-mutation that projected us into a supra-biological space of existence that is new to natural history. It is not clear whether this event will lead to a positive future for humanity or to doom. Functional religion is seen as a neurosystemic attempt to bring back the earlier natural state. Thus, it can be valuable when cleared of mythological ballast. (shrink)

We hypothesize that heritable epigenetic changes can affect rates of fitness increase as well as patterns of genotypic and phenotypic change during adaptation. In particular, we suggest that when natural selection acts on pure epigenetic variation in addition to genetic variation, populations adapt faster, and adaptive phenotypes can arise before any genetic changes. This may make it difficult to reconcile the timing of adaptive events detected using conventional population genetics tools based on DNA sequence data with environmental drivers of adaptation, (...) such as changes in climate. Epigenetic modifications are frequently associated with somatic cell differentiation, but recently epigenetic changes have been found that can be transmitted over many generations. Here, we show how the interplay of these heritable epigenetic changes with genetic changes can affect adaptive evolution, and how epigenetic changes affect the signature of selection in the genetic record. (shrink)

There is increasing evidence for epigenetically mediated transgenerational inheritance across taxa. However, the evolutionary implications of such alternative mechanisms of inheritance remain unclear. Herein, we show that epigenetic mechanisms can serve two fundamentally different functions in transgenerational inheritance: (i) selection-based effects, which carry adaptive information in virtue of selection over many generations of reliable transmission; and (ii) detection-based effects, which are a transgenerational form of adaptive phenotypic plasticity. The two functions interact differently with a third form of epigenetic information transmission, (...) namely information about cell state transmitted for somatic cell heredity in multicellular organisms. Selection-based epigenetic information is more likely to conflict with somatic cell inheritance than is detection-based epigenetic information. Consequently, the evolutionary implications of epigenetic mechanisms are different for unicellular and multicellular organisms, which underscores the conceptual and empirical importance of distinguishing between these two different forms of transgenerational epigenetic effect. (shrink)

Molecular Weismannism is the claim that: “In the development of an individual, DNA causes the production both of DNA (genetic material) and of protein (somatic material). The reverse process never occurs. Protein is never a cause of DNA”. This principle underpins both the idea that genes are the objects upon which natural selection operates and the idea that traits can be divided into those that are genetic and those that are not. Recent work in developmental biology and in philosophy (...) of biology argues that an acceptance of Molecular Weismannism requires the tacit assumption that genetic causes are different in kind from other developmental causes. They argue that if this assumption proves to be unwarranted then we should abandon, not just gene selectionism and gene centred functional solutions to the units of selection problem, but also the very notion that there is any such thing as a “genetic trait”. A group of possible causal distinctions (proximity, ultimacy and specificity) are explored and found wanting. It is argued that an extended version of information theory, while not strong enough to support Molecular Weismannism, will support both the claim that traits can be divided into those that are genetic and those that are not as well as the claim that there is good reason to privilege genetic causes within evolutionary and developmental explanations. The outcome of this for the units of selection debate is explored. (shrink)

Somatic diversification of antigen receptor genes depends on the activity of enzymes whose homologs participate in a mutagenic DNA repair in unicellular species. Indeed, by engaging error-prone polymerases, gap filling molecules and altered mismatch repair pathways, lymphocytes utilize conserved components of genomic stress response systems, which can already be found in bacteria and archaea. These ancient systems of mutagenesis and repair act to increase phenotypic diversity of microbial cell populations and operate to enhance their ability to produce fit variants (...) during stress. Coopted by lymphocytes, the ancient mutagenic processing systems retained their diversification functions instilling the adaptive immune cells with enhanced evolvability and defensive capacity to resist infection and damage. As reviewed here, the ubiquity and conserved character of specialized variation-generating mechanisms from bacteria to lymphocytes highlight the importance of these mechanisms for evolution of life in general. (shrink)

Since Darwin, the idea of psychological continuity between humans and other animals has dominated theory and research in investigating the minds of other species. Indeed, the field of comparative psychology was founded on two assumptions. First, it was assumed that introspection could provide humans with reliable knowledge about the causal connection between specific mental states and specific behaviors. Second, it was assumed that in those cases in which other species exhibited behaviors similar to our own, similar psychological causes were at (...) work. In this paper. we show how this argument by analogy is flowed with respect to the case of second-order mental states. As a test case, we focus on the question of how other species conceive of visual attention, and in particular whether chimpanzees interpret seeing as a mentalistic event involving internal states of perception, attention, and belief. We conclude that chimpanzees do not reason about seeing in this manner, and indeed, there is considerable reason to suppose that they do not harbor representations of mental states in general. We propose a reinterpretation model in which the majority of the rich social behaviors that humans and other primates share in common emerged long before the human lineage evolved the psychological means of interpreting those behaviors in mentalistic terms. Although humans, chimpanzees, and most other species may be said to possess mental states, humans alone may have evolved a cognitive specialization for reasoning about such states. (shrink)

From an evolutionary perspective, both atavism and somatic evolution/convergent evolution theories can account for the consistent occurrence, and astounding attributes of cancers: being able to evolve from a single cell to a complex organized system, and malignant transformations showing significant similarities across organs, individuals, and species. Here, we first provide an overview of these two hypotheses, including the possibility of them not being mutually exclusive, but rather potentially representing the two extremes of a continuum in which the (...) diversity of cancers can emerge. In reviewing the current literature, we also discuss the criteria that should be applied to discriminate between the two competing theories and to determine their relevant contributions to oncogenesis and cancer progression. Finally, we deliberate on the potential applications of this conceptual framework in developing novel treatment strategies. (shrink)

The aim of this paper is to assess the relevance of somatic evolution by natural selection to our understanding of cancer development. I do so in two steps. In the first part of the paper, I ask to what extent cancer cells meet the formal requirements for evolution by natural selection, relying on Godfrey-Smith’s (2009) framework of Darwinian populations. I argue that although they meet the minimal requirements for natural selection, cancer cells are not paradigmatic Darwinian populations. (...) In the second part of the paper, I examine the most important examples of adaptation in cancer cells. I argue that they are not significant accumulations of evolutionary changes, and that as a consequence natural selection plays a lesser role in their explanation. Their explanation, I argue, is best sought in the previously existing wiring of the healthy cells. (shrink)

In response to Germain argument that evolution by natural selection has a limited explanatory power in cancer, Lean and Plutynski have recently argued that many adaptations in cancer only make sense at the tumor level, and that cancer progression mirrors the major evolutionary transitions. While we agree that selection could potentially act at various levels of organization in cancers, we argue that tumor-level selection is unlikely to actually play a relevant role in our understanding of the somatic (...) class='Hi'>evolution of human cancers. (shrink)

Recently, Quyn et al. demonstrated that cells within the stem cell zone of human and mouse intestinal crypts tend to align their mitotic spindles perpendicular to the basal membrane of the crypt. This is associated with asymmetric division, whereby particular proteins and individual chromatids are preferentially segregated to one daughter cell. In colonic mucosa containing a heterozygous adenomatous polyposis coli gene (APC) mutation the asymmetry is lost. Here, we discuss asymmetric stem cell division as an anti‐tumourigenic mechanism. We describe how (...) hierarchical tissue structures suppress somatic evolution, and discuss the relative merits of template strand retention to limit the accumulation of DNA replication errors. We suggest experiments to determine whether somatic mutations resulting in loss of spindle alignment confer an advantage within the stem cell niche. Finally, we discuss whether lack of spindle alignment constitutes an oncogenic event per se, with particular reference to studies in model organisms, and the timing of chromosomal instability in human cancers. (shrink)

There is disagreement in the literature about the exact nature of the phenomenon of empathy. There are emotional, cognitive, and conditioning views, applying in varying degrees across species. An adequate description of the ultimate and proximate mechanism can integrate these views. Proximately, the perception of an object's state activates the subject's corresponding representations, which in turn activate somatic and autonomic responses. This mechanism supports basic behaviors that are crucial for the reproductive success of animals living in groups. The Perception-Action (...) Model, together with an understanding of how representations change with experience, can explain the major empirical effects in the literature. It can also predict a variety of empathy disorders. The interaction between the PAM and prefrontal functioning can also explain different levels of empathy across species and age groups. This view can advance our evolutionary understanding of empathy beyond inclusive fitness and reciprocal altruism and can explain different levels of empathy across individuals, species, stages of development, and situations. Key Words: altruism; cognitive empathy ; comparative; emotion; emotional contagion; empathy ; evolution; human; perception-action; perspective taking. (shrink)

The evolution-revolution of 20th century man toward the somatic culture of the 21st century.

The de‐repression of transposable elements (TEs) in mammalian genomes is thought to contribute to genome instability, inflammation, and ageing, yet is viewed as a cell‐autonomous event. In contrast to mammalian cells, prokaryotes constantly exchange genetic material through TEs, crossing both cell and species barriers, contributing to rapid microbial evolution and diversity in complex communities such as the mammalian gut. Here, it is proposed that TEs released from prokaryotes in the microbiome or from pathogenic infections regularly cross the kingdom barrier (...) to the somatic cells of their eukaryotic hosts. It is proposed this horizontal transfer of TEs from microbe to host is a stochastic, ongoing catalyst of genome destabilization, resulting in structural and epigenetic variations, and activation of well‐evolved host defense mechanisms contributing to inflammation, senescence, and biological ageing. It is proposed that innate immunity pathways defend against the horizontal acquisition of microbial TEs, and that activation of this pathway during horizontal transposon transfer promotes chronic inflammation during ageing. Finally, it is suggested that horizontal acquisition of prokaryotic TEs into mammalian genomes has been masked and subsequently under‐reported due to flaws in current sequencing pipelines, and new strategies to uncover these events are proposed. (shrink)

Aesthetics, like other philosophical subjects, has historically made use of «top down» methods. Recent discoveries in genetics, evolutionary psychology, paleoarchaeology, and neuroscience call for a new «naturalistic» or «bottom up» perspective. Combining these fields with behavioral biology and ethnoarts studies, I offer seven premises that underlie a new understanding of evolved predispositions of the brain/mind that all artists use to attract attention, sustain interest, and create, mold, and shape emotion. I describe aesthetic «primitives» in somatic and behavioral modalities, suggesting (...) that these were present in early sapiens and continue to influence human art making and aesthetic response today. Keywords: Aesthetic Mind; Neuroaesthetics, evolutionary aesthetics, cognitive aesthetics, evolution of art. (shrink)

Herbert Spencer was one of the most important contributors to the Victorian discourse on social evolution. His theory of evolution in nature and society has been the subject of countless scholarly works over the last hundred years. Nevertheless, not all of its dimensions have been studied in due depth. Contrary to a widespread belief, Spencer did not just design an evolutionary theory of upward, yet branched development. Searching for explanations for the social distance between presumably civilized and primitive (...) societies and between presumably well-conducted and pauperized Victorians, he introduced elements of retrogression into his theory of social evolution. In addition, he biologized social structures and social phenomena by constructing a causal relationship between social and somatic features. This article discusses Spencer's account of the social conditions of the so-called savages and paupers. It aims to shed light on the progressive and retrogressive modes of evolutionary development and the biologistic explanations he employed in his social theory to explain these conditions. (shrink)

Herbert Spencer was one of the most important contributors to the Victorian discourse on social evolution. His theory of evolution in nature and society has been the subject of countless scholarly works over the last hundred years. Nevertheless, not all of its dimensions have been studied in due depth. Contrary to a widespread belief, Spencer did not just design an evolutionary theory of upward, yet branched development. Searching for explanations for the social distance between presumably civilized and primitive (...) societies and between presumably well-conducted and pauperized Victorians, he introduced elements of retrogression into his theory of social evolution. In addition, he biologized social structures and social phenomena by constructing a causal relationship between social and somatic features. This article discusses Spencer's account of the social conditions of the so-called savages and paupers. It aims to shed light on the progressive and retrogressive modes of evolutionary development and the biologistic explanations he employed in his social theory to explain these conditions. (shrink)

Several models of the evolution of religion claim that ritual creates “religion” and gives it a positive evolutionary role. Robert Bellah suggests that the evolutionary roots of ritual lay in the play of animals. For Homo sapiens, Bellah argues, rituals generate a world of experience different from the world of everyday life, and that different world of experience is the foundation of later religious developments. Robin Dunbar points to trance dancing as the original religious behavior. Trance dancing both alters (...) ordinary consciousness and generates trance experiences that will give rise to religious concepts and also, through the production of endorphins, bonds people into tight-knit social groups whose social bonding gives them a survival advantage. The role of ritual in social bonding has been well established through the research on the production of endorphins by synchronized activity and the role of endorphins in social bonding. The role of ritual in generating religious experience has been much less developed. Drawing on the extensive research on the ways in which bodily activity can impact and transform our sensory and cognitive processes, and the ways in which sensory and cognitive processes are neurologically connected with somatic processes, this article will propose one neuropsychological model of how ritual activity might give rise to religion. Starting from bodily activity means that here religion will be understood more as a set of practices and less as a set of beliefs. Theological implications of this model will be discussed. (shrink)

CRISPR keeps me up at night. I marvel at its potential to cure insidious genetic diseases and scourges like malaria. I shudder at the ways it might be misused to create biological weapons. What frightens me most, though, is what I can't predict: how will we use CRISPR? How will it change evolution? How will it redefine the very nature of our existence?CRISPR is an ingenious cut-and-paste system that homes in on a particular DNA gene sequence and then, using (...) Cas9 enzymes, snips it out. That sequence is then replaced with a new one that rewrites or repairs the original. Two different cells—somatic, from the body, and germline, from gametes—can be manipulated... (shrink)

The presence of fetal cells has been associated with both positive and negative effects on maternal health. These paradoxical effects may be due to the fact that maternal and offspring fitness interests are aligned in certain domains and conflicting in others, which may have led to the evolution of fetal microchimeric phenotypes that can manipulate maternal tissues. We use cooperation and conflict theory to generate testable predictions about domains in which fetal microchimerism may enhance maternal health and those in (...) which it may be detrimental. This framework suggests that fetal cells may function both to contribute to maternal somatic maintenance (e.g. wound healing) and to manipulate maternal physiology to enhance resource transmission to offspring (e.g. enhancing milk production). In this review, we use an evolutionary framework to make testable predictions about the role of fetal microchimerism in lactation, thyroid function, autoimmune disease, cancer and maternal emotional, and psychological health.Also watch the Video Abstract. (shrink)

The genome is a stable repository of vastly intricate genetic information developed over eons of evolution; this information is replicated at the highest fidelity and expressed within each cell at the highest selectivity. Non‐leukemia cancers break this standard; the intricate genetic information qualitatively and progressively deteriorates, resulting in a somatic Darwinian free‐for‐all. In a process lasting several years, a genomically heterogeneous population replicates from a single cell that originally lost the ability to preserve its genomic integrity. Cells selected (...) for their abilities to proliferate and spread, while evading host defenses, inexorably expand their numbers. The clinical consequences of this become severe, as the genomically diverse cell population that evolves contains members that can evade most therapeutic approaches aimed at “the tumor cell”. BioEssays 23:1037–1046, 2001. © 2001 John Wiley & Sons, Inc. (shrink)

In multicellular organisms, cells are frequently programmed to die. This makes good sense: cells that fail to, or are no longer playing important roles are eliminated. From the cell’s perspective, this also makes sense, since somatic cells in multicellular organisms require the cooperation of clonal relatives. In unicellular organisms, however, programmed cell death poses a difficult and unresolved evolutionary problem. The empirical evidence for PCD in diverse microbial taxa has spurred debates about what precisely PCD means in the case (...) of unicellular organisms. In this article, we survey the concepts of PCD in the literature and the selective pressures associated with its evolution. We show that definitions of PCD have been almost entirely mechanistic and fail to separate questions concerning what PCD fundamentally is from questions about the kinds of mechanisms that realize PCD. We conclude that an evolutionary definition is best able to distinguish PCD from closely related phenomena. Specifically, we define “true” PCD as an adaptation for death triggered by abiotic or biotic environmental stresses. True PCD is thus not only an evolutionary product but must also have been a target of selection. Apparent PCD resulting from pleiotropy, genetic drift, or trade-offs is not true PCD. We call this “ersatz PCD.”. (shrink)