A couple may have a child to provide stem cells for another child. They may also use preimplantation testing—even, troubling though it is, prenatal testing and selective abortion—to ensure a close tissue match.

Successful preimplantation genetic diagnosis to avoid creating a child affected by a genetically-based disorder was reported in 1989. Since then PGD has been used to biopsy and analyze embryos created through in viuo fertilization to avoid transferring to the mother’s uterus an embryo affected by a mutation or chromosomal abnormality associated with serious illness. PGD to avoid serious and early-onset illness in the child-to-be is widely accepted. PGD prevents gestation of an affected embryo and reduces the chance that the parents (...) will be faced with a difficult decision of whether to terminate the pregnancy. More controversial have been PGD to select the sex of the child-to-be for “family balancing”, PGD for mere susceptibility to disease and for late-onset disorders such as Alzheimer diseas, and most controversially, PGD to create a donor child who is Human Leukocyte Antigen (HLA-matched with a preexisting sibling in need of stem cell transplant. (shrink)

Successful preimplantation genetic diagnosis to avoid creating a child affected by a genetically-based disorder was reported in 1989. Since then PGD has been used to biopsy and analyze embryos created through in viuo fertilization to avoid transferring to the mother’s uterus an embryo affected by a mutation or chromosomal abnormality associated with serious illness. PGD to avoid serious and early-onset illness in the child-to-be is widely accepted. PGD prevents gestation of an affected embryo and reduces the chance that the parents (...) will be faced with a difficult decision of whether to terminate the pregnancy. More controversial have been PGD to select the sex of the child-to-be for “family balancing”, PGD for mere susceptibility to disease and for late-onset disorders such as Alzheimer diseas, and most controversially, PGD to create a donor child who is Human Leukocyte Antigen (HLA-matched with a preexisting sibling in need of stem cell transplant. (shrink)

Successful preimplantation genetic diagnosis (PGD) to avoid creating a child affected by a genetically-based disorder was reported in 1989. Since then PGD has been used to biopsy and analyze embryos created through in viuo fertilization (IVF) to avoid transferring to the mother’s uterus an embryo affected by a mutation or chromosomal abnormality associated with serious illness. PGD to avoid serious and early-onset illness in the child-to-be is widely accepted. PGD prevents gestation of an affected embryo and reduces the chance that (...) the parents will be faced with a difficult decision of whether to terminate the pregnancy. More controversial have been PGD to select the sex of the child-to-be for “family balancing” (rather than to avoid a sex-linked disorder), PGD for mere susceptibility to disease and for late-onset disorders such as Alzheimer diseas, and most controversially, PGD to create a donor child who is Human Leukocyte Antigen (HLA-matched with a preexisting sibling in need of stem cell transplant. (shrink)

The article compares the COVID-19 pandemic and climate change in terms of natural characteristics of the crisis triggers as well as of socio-political responses.

" Because characters and the conception of characters are central to all studies of evolution, and because evolution is the central organizing principle of biology, this book will appeal to a wide cross-section of biologists.

Understanding the evolutionary role of environmentally induced phenotypic variation (i.e., plasticity) is an important issue in developmental evolution. A major physiological response to environmental change is cellular stress, which is counteracted by generic stress reactions detoxifying the cell. A model, stress‐induced evolutionary innovation (SIEI), whereby ancestral stress reactions and their corresponding pathways can be transformed into novel structural components of body plans, such as new cell types, is described. Previous findings suggest that the cell differentiation cascade of a cell type (...) critical to pregnancy in humans, the decidual stromal cell, evolved from a cellular stress reaction. It is hypothesized that the stress reaction in these cells was elicited ancestrally via inflammation caused by embryo attachment. The present study proposes that SIEI is a distinct form of plasticity‐based evolutionary change leading to the origin of novel structures rather than adaptive transformation of pre‐existing characters. (shrink)

This book, which represents probably the most comprehensive discussion of the emergence of modem social science yet produced, is of far more than merely historical interest. The contributors set out to rewrite the history of the social sciences and to show the limitations of conventional conceptions of their development. These tasks they accomplish with great success and much distinction. Yet in so doing they contribute in a direct way to our understanding of the relation between social analysis and the nature (...) of human societies today. The brilliant and distinctive perspective of the papers in this collection is to demonstrate, with many specific examples, that social science and modem institutions have helped shape each other in mutual interplay. Modem systems are in some part con stituted through the reflexive incorporation of developing social science knowledge; on the other hand, the social sciences organise themselves in terms of a continuing reflection upon the evolution of those systems. Such a perspective, as Wagner and Wittrock in particular make clear, does not in any way either impugn the status of knowledge claims made within social science or destroy the independent reality of social institutions. The book questions the notion that the institutionalising of the social sciences can be understood as a process of their increasing autonomy from extemal social connections. 'Autonomy' forms a mode of legitima tion and a basis of power rather than a distinctive phenomenon as such. (shrink)

Two welcome extensions of evolutionary thinking have come to prominence over the last thirty years: the so-called ’extended evolutionary synthesis’ (EES) and debate about biological kinds and individuals. These two agendas have, however, remained orthogonal to one another. The EES has mostly restricted itself to widening the explanations of adaptation offered by the preceding ’modern evolutionary synthesis’ by including additional mechanisms of inheritance and variation; while discussion of biological kinds has turned toward philosophical questions of essential vs. contingent properties of (...) life forms and realist vs. epistemological approaches to categorization and classification. Here we attempt to broaden the explanatory scope of evolutionary theory by linking these two agendas. We expand on the mechanistic orientation of the EES, using new understandings of networked systems of components in order to engage the distinct intellectual challenge of the origination of “historical kinds”. With this phrase we designate a subset of natural kinds that acquires, through evolutionary processes, a quasi-independent lineage-history. Such kinds emerge in both biology and culture, and we enlarge the limited number of historical kinds that have thus far been recognized in evolutionary biology in a series of paradigmatic exemplars, from genes and cell types to rituals and music. For each exemplar we discern specific mechanisms by which it arose and persists; comparing these, we suggest a general unity in the ways in which diverse historical kinds originate. (shrink)

This chapter offers an essay on the evolution of evolvability. It investigates the most frequently cited arguments against the possibility that the evolution of evolvability might be the result of selection favoring more evolvable genotypes. The chapter argues that all these arguments have not been rigorously analyzed by their proponents, and are thus a self-inflicted blind spot in evolutionary biology, and indicates that there are no deep conceptual obstacles for population genetic theory to explain the evolution of evolvability. The very (...) focus on this subject will help shift the perspective of evolutionary biology toward a more holistic, systemic view of evolution. (shrink)

In this paper we argue that an operational organism concept can help to overcome the structural deficiency of mathematical models in biology. In our opinion, the structural deficiency of mathematical models lies mainly in our inability to identify functionally relevant biological characters in biological systems, and not so much in a lack of adequate mathematical representations of biological processes. We argue that the problem of character identification in biological systems is linked to the question of a properly formulated organism concept. (...) Lastly, we demonstrate how a decomposition of an organism into independent characters in the context of a specific biological process--such as adaptation by means of natural selection--depends on the dynamical properties and invariance conditions of the equations that describe this process. (shrink)

This paper responds to the essay reviews by David Haig, Alan Love and Rachel Brown of my recently published book “Homology, Genes and Evolutionary Innovation”. The issues addressed here relate to: the notion of classes and individuals, issues of explanatory value of adaptive and structuralist explanations in evolutionary biology, the role of homology in evolutionary theory, the limits of a pluralist stance vis a vis alternative explanations of homology, as well as the question whether and to what extend the perspective (...) laid out in HGEI can be or should be transferred to other branches of study, like comparative behavioral biology. (shrink)

In this paper we critically examine and seek to extend Philip Kitcher’s Ethical Project to weave together a distinctive naturalistic conception of how ethics came to occupy the place it does in our lives and how the existing ethical project should be revised and extended into the future. Although we endorse his insight that ethical progress is better conceived of as the improvement of an existing state than an incremental approach towards a fixed endpoint, we nonetheless go on to argue (...) that the metaethical apparatus Kitcher constructs around this creative metaethical proposal simply cannot do the work that he demands of it. The prospect of fundamental conflict between different functions of the ethical project requires Kitcher to appeal to a particular normative stance in order to judge specific changes in the ethical project to be genuinely progressive, and we argue that the virtues of continuity and coherence to which he appeals can only specify rather than justify the normative stance he favors. We conclude by suggesting an alternative approach for ethical naturalists that seems to us ultimately more promising than Kitcher’s own. (shrink)

The problem of modifier evolution was examined with regard to the idea that modifier evolution can be considered as a result of selection for adaptation speed in populations far from equilibrium. This kind of selection was called feedback selection in order to emphasize the difference to theories which consider modifier evolution near the equilibrium. The basic principles of this kind of selection are derived for asexual populations and the problem of dominance is discussed in the light of this concept. In (...) general the results support the view, that the genetic properties of a character are selected along with the character itself. (shrink)

It is widely accepted that stressful conditions can facilitate evolutionary change. The mechanisms elucidated thus far accomplish this with a generic increase in heritable variation that facilitates more rapid adaptive evolution, often via plastic modifications of existing characters. Through scrutiny of different meanings of stress in biological research, and an explicit recognition that stressors must be characterized relative to their effect on capacities for maintaining functional integrity, we distinguish between: (1) previously identified stress-responsive mechanisms that facilitate evolution by maintaining an (...) adaptive fit with the environment, and (2) the co-option of stress-responsive mechanisms that are specific to stressors leading to the origin of novelties via compensation. Unlike standard accounts of gene co-option that identify component sources of evolutionary change, our model documents the cost-benefit trade-offs and thereby explains how one mechanism—an immediate response to acute stress—is transformed evolutionarily into another—routine protection from recurring stressors. We illustrate our argument with examples from cell type origination as well as processes and structures at higher levels of organization. These examples suggest a general principle of evolutionary origination based on the capacity to switch between regulatory states related to reproduction and proliferation versus survival and differentiation. (shrink)

Given the pervasiveness of gene sharing in evolution and the extent of homology across the tree of life, why is everything not homologous with everything else? The continuity and overlapping genetic contributions to diverse traits across lineages seem to imply that no discrete determination of homology is possible. Although some argue that the widespread overlap in parts and processes should be acknowledged as “partial” homology, this threatens a broad base of presumed comparative morphological knowledge accepted by most biologists. Following a (...) long scientific tradition, we advocate a strategy of “theoretical articulation” that introduces further distinctions to existing concepts to produce increased contrastive resolution among the labels used to represent biological phenomena. We pursue this strategy by drawing on successful patterns of reasoning from serial homology at the level of gene sequences to generate an enriched characterization of serial homology as a hierarchical, phylogenetic concept. Specifically, we propose that the concept of serial homology should be applied primarily to repeated but developmentally individualized body parts, such as cell types, differentiated body segments, or epidermal appendages. For these characters, a phylogenetic history can be reconstructed, similar to families of paralogous genes, endowing the notion of serial homology with a hierarchical, phylogenetic interpretation. On this basis, we propose a five-fold theoretical classification that permits a more fine-grained mapping of diverse trait-types. This facilitates answering the question of why everything is not homologous with everything else, as well as how novelty is possible given that any new character possesses evolutionary precursors. We illustrate the fecundity of our account by reference to debates over insect wing serial homologs and vertebrate paired appendages. (shrink)

A central topic in research at the intersection of development and evolution is the origin of novel traits. Despite progress on understanding how developmental mechanisms underlie patterns of diversity in the history of life, the problem of novelty continues to challenge researchers. Here we argue that research on evolutionary novelty and the closely associated phenomenon of co-option can be reframed fruitfully by: (1) specifying a conceptual model of mechanisms that underwrite character identity, (2) providing a richer and more empirically precise (...) notion of co-option that goes beyond common appeals to “deep homology”, and (3) attending to the nature of experimental interventions that can determine whether and how the co-option of identity mechanisms can help to explain novel character origins. This reframing has the potential to channel future investigation to make substantive progress on the problem of evolutionary novelty. To illustrate this potential, we apply our reframing to two case studies: treehopper helmets and beetle horns. (shrink)

This paper argues in defense of theanti-reductionist consensus in the philosophy ofbiology. More specifically, it takes issues with AlexRosenberg's recent challenge of this position. Weargue that the results of modern developmentalgenetics rather than eliminating the need forfunctional kinds in explanations of developmentactually reinforce their importance.