IAS-Research Talk by Gabriel Piedrafita: Tissue-level cell-fate coordination underpins epithelial clone competition dynamics: theoretical modeling to open a conceptual discussion

Date and time: September 25, Tuesday, 11:30 a.m.

Location: Carlos Santamaría Building, Room B14.

Speaker: Gabriel Piedrafita, Wellcome Trust Sanger Institute (Cambridge, UK)

Title: Tissue-level cell-fate coordination underpins epithelial clone competition dynamics: theoretical modeling to open a conceptual discussion

Abstract: Epithelia are among the simplest mammalian tissues. Yet, little is known about how epithelial cells organize and orchestrate their fates (whether to divide, differentiate or die) to guarantee the turnover while preserving tissue homeostasis. Over a decade, theoretical models have been proposed according to which individual progenitor cell behavior would accommodate toautonomous, random fate choices, with remarkably good fits – at a statistical level – on lineage-tracing data from transgenic mice. It was my aim in this work to revisit these studies, and re-evaluate previous paradigms with an emphasis on bringing statistical-physics descriptions closer to the biological phenomenology at the cell level. By means of new experimental data and mathematical modeling, I will show how epithelial homeostasis can conform to simple rules where niche-sensing and collective cell-fate coordination play a predominant role. I would like to finish discussing how this domain of tissue-level communication would necessary constrain and impact on mutant clonal expansion, contributing to an internal control of tumourogenesis, letting the topic open for further debate.

Talk by Nathalie Gontier: Roots of reticulate evolutionary theories in natural philosophy

Date and time: May 15, Tuesday, 11:30 a.m.

Location: Carlos Santamaría Building, Room B14.

Speaker: Nathalie Gontier (Center for Philosophy of Sciences of the University of Lisbon)

Title: Roots of reticulate evolutionary theories in natural philosophy

Abstract: 

Symbiosis, symbiogenesis, hybridization, virolution and infectious heredity are forms of reticulate evolution that are currently drawing the attention of philosophers of science because of the discussions they raise on the origin of life and the diversification of major cell types, the nature of biological individuality, and the limited scope of the traditional Modern Synthesis in defining and explaining all aspects of life’s evolution. Research on the innovative nature of reticulate evolution currently overshadows inquiries into the scientific and sociocultural context wherein these ideas first emerged. Hybridization theories were first formulated in relation to the ethnic mixing induced by colonialism and imperialism, with religious, political and scientific leaders speaking out against the mixing of ethnicities – an idea also endorsed by the eugenicist founders of the Modern Synthesis. Symbiosis and symbiogenesis associate with the rise of communitarian and socialist ideologies that opposed liberal ideas of free market economy that in turn associate with natural selection theory. And research on virolution and infectious heredity associates with attempts at eradicating disease. All aspects of reticulate evolution thus originally carried a negative sociocultural connotation. To understand why reticulate evolution has long been researched outside the mainstream Neodarwinian framework, it is necessary to go beyond comparing these theoretical frameworks from within science and the role they play in evolution, and to take the sociocultural, political and historical aspects into account.