Abstract:

I will provide not a philosophical approach but a historical approach and an overview of "evo-devo" as it was and is today. In my own mind, evo-devo goes back to Balfour and Gegenbaur (and Haeckel) and the evolutionary morphologists of the 1870s and 1880s. I trace the historical line from there to the gap after Mendel's work was rediscovered, including the efforts of individuals such as Garstang, de Beer, Waddington, Schmalhausen to keep evo-devo or genet-devo-evo going. Then I will discuss the seminal events in the 1970s – the development of a theory of homeobox genes in Gould's Ontogeny and Phylogeny, Bonner's Dahlem conference volume, and the rise of phylogenetics and comparative approaches.

Suggested Readings:

Hall, B. K. (2000). Balfour, Garstang and de Beer: the first century of evolutionary embryology. Amer. Zool. 40: 718-728.

Hall, B. K. (2003). Unlocking the Black Box between Genotype and Phenotype: Cell Condensations as Morphogenetic (modular) Units Biol. & Philos. 18: 219-247. (Special issue devoted to evolutionary developmental biology)

Hall, B. K. (2003). Evo-devo: Evolutionary developmental mechanisms. Int. J. Devel. Biol. (special issues devoted to Evolutionary developmental Biology) 47: 491-495.

Hall, B. K. (2005). Evo-devo is the new buzzword?for the 200-year-old search for links between embryos and evolution. Sci. Amer. 292 (4): 86-87.

Hall, B. K. (2006). Tapping Many Sources: The Adventitious Roots of Evo-Devo in the 19th Century. In From Embryology to Evo-Devo: A History of Developmental Evolution (M. D. Laubichler and J. Maienschein), pp. 467-497. Symposium of the Dibner Institute for the History of Science, MIT. MIT Press, Cambridge, MA. [This should be in print by March]

Roberta L. Millstein: The Nearly Neutral Theory of Evo-Devo?

Abstract:

Recent work on heat shock protein 90 (HSP 90) by Rutherford and Lindquist (1998) has been included among the pieces of evidence taken to show the essential role of developmental processes in evolution; HSP 90 acts as a buffer against pheonotypic variation, allowing genotypic variation to build.  When the buffering capacity of HSP 90 is altered (e.g., in nature, by mutation or environmental stress), the genetic variation is "revealed," manifesting itself as phenotypic variation.  This phenomenon raises questions about the genetic variation before and after what I will call a "revelation event":  Is it neutral, nearly neutral, or non-neutral (i.e., strongly deleterious or strongly advantageous)?  Moreover, what kinds of evolutionary processes do we take to be at work?  Rutherford and Lindquist (1998) focus on the implications of non-neutral variation and selection.  Later work by Queitsch, Sangster, and Lindquist (2002) and Sangster, Lindquist, and Queitsch (2004) raises the possibility that HSP 90 buffering may play the role that was played by drift in Sewall Wright's shifting balance model, permitting transition from one adaptive peak to another.  However, Ohta (2002) suggests that much of this variation may be nearly neutral, which in turn, would imply a strong role for drift as well as selection.  The goal of this presentation is to clarify the competing claims and their implications for evolutionary developmental processes.

Suggested Readings:

"Hsp90 as a Capacitor for morphological evolution" by Suzanne L. Rutherford & Susan Lindquist

"Under cover: causes, effects and implications of Hsp90-mediated genetic capacitance" by Todd A. Sangster, Susan Lindquist and Christine Queitsch

"Near-neutrality in evolution of genes and gene regulation" by Tomoko Ohta

Jason Scott Robert: Evolutionary Developmental Medicine

Abstract:

Beginning with the historical and conceptual foundations of evo-devo, I engage recent and emerging experimental and theoretical research in evo-devo with particular attention to evolutionary aspects of the development of disease. I discuss the evolution of developmental pathways and processes of disease, and my primary focus is on the mutual interrelations between the development and evolution of organism-disease systems. Some examples include homeobox genes in evelopment and disease; cancer epigenetics; heat shock protein 90 and its role as a developmental buffer against the emergence of deleterious phenotypes; and evo-devo and AIDS. The aim of this presentation is to provide a framework for answers to persistent questions about the origins and ontogeny of simple and, more interestingly, complex human diseases.

Suggested Readings:

"Early Life Events and Their Consequences for Later Disease: A Life History and Evolutionary Perspective" by Peter D. Gluckman, Mark A. Hanson, and Alan S. Beedle

"Medicine Needs Revolution" by Randolph M. Nesse, et al.

"How developmental is evolutionary developmental biology?" by Jason Scott Robert

Sponsored by the Department of Philosophy, College of Humanities at California State University Northridge, CSUN Distinguished Speakers Program.

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2005 CSUN Philosophy of Biology Conference

2006 CSUN Philosophy of Biology Conference