Through an examination of the actual research strategies and assumptions underlying the Human Genome Project (HGP), it is argued that the epistemic basis of the initial model organism programs is not best understood as reasoning via causal analog models (CAMs). In order to answer a series of questions about what is being modeled and what claims about the models are warranted, a descriptive epistemological method is employed that uses historical techniques to develop detailed accounts which, in turn, help to reveal (...) forms of reasoning that are explicit, or more often implicit, in the practice of a particular field of scientific study. It is suggested that a more valid characterization of the reasoning structure at work here is a form of case-based reasoning. This conceptualization of the role of model organisms can guide our understanding and assessment of these research programs, their knowledge claims and progress, and their limitations, as well as how we educate the public about this type of biomedical research. (shrink)

The question of the influence of genes on behavior raises difficult philosophical and social issues. In this paper I delineate what I call the Developmentalist Challenge (DC) to assertions of genetic influence on behavior, and then examine the DC through an indepth analysis of the behavioral genetics of the nematode, C. elegans, with some briefer references to work on Drosophila. I argue that eight "rules" relating genes and behavior through environmentally-influenced and tangled neural nets capture the results of developmental and (...) behavioral studies on the nematode. Some elements of the DC are found to be sound and others are criticized. The essay concludes by examining the relations of this study to Kitcher's antireductionist arguments and Bechtel and Richardson's decomposition and localization heuristics. Some implications for human behavioral genetics are also briefly considered. (shrink)

Through an examination of the actual research strategies and assumptions underlying the Human Genome Project, it is argued that the epistemic basis of the initial model organism programs is not best understood as reasoning via causal analog models. In order to answer a series of questions about what is being modeled and what claims about the models are warranted, a descriptive epistemological method is employed that uses historical techniques to develop detailed accounts which, in turn, help to reveal forms of (...) reasoning that are explicit, or more often implicit, in the practice of a particular field of scientific study. It is suggested that a more valid characterization of the reasoning structure at work here is a form of case-based reasoning. This conceptualization of the role of model organisms can guide our understanding and assessment of these research programs, their knowledge claims and progress, and their limitations, as well as how we educate the public about this type of biomedical research. (shrink)

The biological sciences have become increasingly reliant on so-called ‘model organisms’. I argue that in this domain, the concept of a descriptive model is essential for understanding scientific practice. Using a case study, I show how such a model was formulated in a preexplanatory context for subsequent use as a prototype from which explanations ultimately may be generated both within the immediate domain of the original model and in additional, related domains. To develop this concept of a descriptive model, I (...) focus on use of the nematode worm Caenorhabditis elegans and the wiring diagrams that were developed as models of its neural structure. In addition, implications of the concept of a descriptive model, particularly its relevance for the data-phenomena distinction as well as its relation to long-standing debates on realism, are briefly examined. (shrink)

The biological sciences have become increasingly reliant on so-called 'model organisms'. I argue that in this domain, the concept of a descriptive model is essential for understanding scientific practice. Using a case study, I show how such a model was formulated in a preexplanatory context for subsequent use as a prototype from which explanations ultimately may be generated both within the immediate domain of the original model and in additional, related domains. To develop this concept of a descriptive model, I (...) focus on use of the nematode worm Caenorhabditis elegans and the wiring diagrams that were developed as models of its neural structure. In addition, implications of the concept of a descriptive model, particularly its relevance for the data-phenomena distinction as well as its relation to long-standing debates on realism, are briefly examined. (shrink)

Although Caenorhabditis elegans was chosen and modified to be an organism that would facilitate a reductionist program for neurogenetics, recent research has provided evidence for properties that are emergent from the neurons. While neurogenetic advances have been made using C. elegans which may be useful in explaining human neurobiology, there are severe limitations on C. elegans to explain any significant human behavior.

Stem cell scientists and ethicists have focused intently on questions relevant to the developmental stage and developmental capacities of stem cells. Comparably less attention has been paid to an equally important set of questions about the nature of stem cells, their common characteristics, their non‐negligible differences and their possible developmental species specificity. Answers to these questions are essential to the project of justly inferring anything about human stem cell biology from studies in non‐human model systems—and so to the possibility of (...) eventually developing human therapies based on stem cell biology. After introducing and discussing these questions, I conclude with a brief discussion of the creation of novel model systems in stem cell biology: human‐to‐animal embryonic chimeras. Such novel model systems may help to overcome obstacles to extrapolation, but they are also scientifically and ethically contentious. BioEssays 26:1005‐1012, 2004. © 2004 Wiley Periodicals, Inc. (shrink)

How does a complex organism develop from a relatively simple, homogeneous mass? The usual answer is: through the (context‐dependent) execution of species‐specific genetic instructions specifying the development of that organism. Commentators are sometimes skeptical of this usual answer, but of course not all commentators, and not always for the same reasons. Here I attempt to lay bare the logical structure of the usual answer through an extended analysis of the heuristics and methodological principles at play in the exploration and explanation (...) of development—and also to show a critical ambiguity that renders the usual answer suspect. (shrink)

The practical criteria by which developmental biologists choose their model systems have evolutionary correlates. The result is a sample that is not merely small, but biased in particular ways, for example towards species with rapid, highly canalized development. These biases influence both data collection and interpretation, and our views of how development works and which aspects of it are important.