Sex is fundamental to many organisms. It is through sexual reproduction that humans, and many metazoans (multicellular eukaryotes in the animal kingdom), propagate our species. For more than 150 years, sexual reproduction within metazoans has been understood to rely on the existence of a discrete category of cells (germ cells) that are usually considered uniquely separate from all other cells in the body (somatic cells), and which form a cell lineage (germline) that is sequestered from all somatic cell lineages. The (...) consideration of germ cells and germline as the lone source of reproductive potential within metazoans has allowed many investigators to place the hereditary and evolutionary burdens of sexually reproducing lineages solely within these cells and cell lineages, making them central to many important topics within biology, such as units of selection, transmission and population genetics, Darwinian evolution, and individuality. Regarding these topics, there is a predominant and shared understanding of germ cells, somatic cells, and the ways in which these two relate to each other that is rarely critically evaluated. In this article, I lay out how germ cells and germline within metazoans are understood by a majority of scientists and philosophers, both now and historically, by sketching out what I call the predominant epistemic framework of germ. I show how this framework conflicts with empirical evidence, propose a series of revisions to realign it with this evidence, and indicate why such revisions are urgently needed by highlighting the case of somatic cell genome editing. (shrink)

This article defends a selective eliminativist position with respect to the concept of “biological lineage” as used in certain areas of contemporary evolutionary biology. We argue that its primary epistemic roles in these contexts—explaining social evolution and cumulative selection—clash with empirical evidence, and that enforcing the concept of “lineage” even obstructs fruitful research avenues in several biological research fields, including phylogenetic research. Drawing on this, we suggest that, in many instances, it would be best to get rid of the concept (...) of “lineage” and think in terms that are more closely aligned with the empirical complexity of the biological world. Specifically, this entails that, instead of looking for the lineage that may have given rise to the entities possessing certain biological characteristics, biologists should generally look for any potential process allowing such possession, with the formation of a lineage just one possibility among many. (shrink)

Phylogenetic models traditionally represent the history of life as having a strictly-branching tree structure. However, it is becoming increasingly clear that the history of life is often not strictly-branching; lateral gene transfer, endosymbiosis, and hybridization, for example, can all produce lateral branching events. There is thus motivation to allow phylogenetic models to have a reticulate structure. One proposal involves the reconciliation of genealogical discordance. Briefly, this method uses patterns of disagreement – discordance – between trees of different genes to add (...) lateral branching events to phylogenetic trees of taxa, and to estimate the most likely cause of these events. I use this practice to argue for: (1) a need for expanded accounts of multiple-models idealization, (2) a distinction between automatic and manual de-idealization, and (3) recognition that idealization may serve the meso-level aims of science in a different way than hitherto acknowledged. (shrink)

This paper introduces the reconstitutor as a comprehensive unit of heredity within the context of evolutionary research. A reconstitutor is the structure resulting from a set of relationships between different elements or processes that are actively involved in the recreation of a specific phenotypic variant in each generation regardless of the biomolecular basis of the elements or whether they stand in a continuous line of ancestry. Firstly, we justify the necessity of introducing the reconstitutor by showing the limitations of other (...) evolutionary conceptions of the unit of heredity, such as the replicator, the reproducer, and the Darwinian individual. We argue that these conceptions are based on the requirement of lineage formation, which we argue to be unnecessary for the existence of evolutionary heredity. In the second part, we introduce the reconstitutor, which we base on the concept of Stability of Traits, and illustrate how it covers cases of hereditary phenomena not covered by the previous accounts. Secondly, we illustrate how the reconstitutor could serve as a platform to rethink ecological inheritance and other forms of inheritance that have been recently introduced under the song/singer model of evolution. (shrink)

The infrahuman speaks to a vast network of thought surrounding the politics of race, nation, and embodiment that had already begun to rise within U.S. public culture by the late nineteenth century.I therefore reappropriate and rehabilitate the infrastructure in a way that pays homage both to its historical moment and to its lasting impact on hierarchies of evolution, hybrid speciation, dehumanization, and conditions of inequality.This project is, to borrow a word sometimes used derisively, “ambitious.” The excavation and refurbishment of concepts (...) is difficult under the best of circumstances, harder still when they involve overtones of existential and moral questions. (shrink)

Cancers are hard to treat, and this is largely because cancer cells evolve and diversify through space and time, in patients. The study of clonal evolution relies on the study of cancer cell lineages, and the cutting of these lineages into clones, each clone representing cancer cells with distinctive properties relevant to cancer development and treatment. This notion of clone implies a (set of) simplification(s) that misrepresents the reality. The simplification has been useful and productive, but I argue that maintaining (...) a critical awareness of what is done through this simplification can also be useful and productive. I distinguish three types of simplifications and show that each can offer a panel of therapeutic alternatives that may complement our arsenal of strategies in the battle against clones. The clinical challenge of better treating cancer partly relies on better defining (delineating) clones, but also partly on the more fundamental way we conceive clones. With or without changing the definition, changes in the way we conceive of clones induce changes in the way we treat clones. (shrink)

In this paper, I show how idealizations contribute to social activities in science, such as the recruitment of experts to a research project. These contributions have not been explicitly discussed by recent philosophical accounts of scientific idealization. These accounts have focused on how idealizations influence activities like scientific theorization, explanation, and modeling. Other accounts focus on how idealizations influence policy-making and science communication. I expand these accounts by exploring the uses of idealized phylogenetic trees in science. Trees are not only (...) useful for improving our understanding and public communication of evolutionary history, but they also help with the organization of laboratories and collaboration among scientists. Attending to the relation between idealizations and these social practices in science matters. It can help us understand why idealized models become entrenched and why certain social practices change over time. (shrink)