What's on in Computing Science?

Date: Thursday, 12 March, 2009
Time: 11:00
Location: Sir Alwyn Williams Building, 422 Seminar Room
[ Inference Seminar ] Network topology depends on evolutionary potential
Tapesh Santra
The mechanism of architectural renovations of an organism's gene regulatory network (GRN) due course of evolution is an active field of study in system's biology and biophysical community. It has been observed by previous researchers that different parts of these networks evolve in different ways. But which parts of a GRN are more plastic towards evolutionary renovations and which parts are rigid against it is not yet clear. In this study, we show that most of the genes and proteins in gene regulatory network (GRN) of Saccharomyces cerevisiae, commonly known as baker's yeast, do not take part in any feedback mechanism, giving rise to a mostly acyclic network structure. Evolutionary changes in these genes and proteins do not affect the global dynamic properties of yeast GRN. Hence, the acyclic part of yeast GRN is highly flexible towards architectural upgrades by evolutionary means. The feedback loops found in yeast GRN reside in form of several clusters by means of coupling and nesting with each other. The clusters of small feedback loops have pivotal role in genetic decision making and are highly rigid against evolutionary renovations. In case of clusters with long feedback mechanisms, the longest feedback loops are essential to its functionality, hence, evolutionarily rigid, and the smaller ones provide plugin type upgrade mechanism to the core module and could be results of beneficial mutations. The feedback mechanisms which produces oscillating dynamics in their normal operating condition have widespread influences on the operation of a GRN and hence are highly unlikely to be structurally altered due course of evolution. Our analysis shed some light on the plasticity of different parts of yeast GRN towards evolutionary changes which in effect can provide us clues to explain many unanswered questions related to evolution, such as, the presence of highly preserved kernel components in mammalian GRNs.

Contact: Dr Rónán Daly (rdaly@dcs.gla.ac.uk)

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