Sergei Maslov, Kim Sneppen, and Kasper Astrup
Eriksen
Upstream Plasticity and Downstream Robustness in
Evolution of Molecular Networks
submitted to BMC Evolutionary Biology
Abstract
Background:
Gene duplication followed by functional divergence of
associated proteins is a major force shaping molecular
networks in living organisms. Recent availability of
system-wide data for yeast S. Cerevisiae allow us to access
the effects of gene duplication on robustness and
plasticity of molecular networks.
Results:
We demonstrate that the upstream transcriptional regulation
of duplicated genes diverges fast, losing on average 4% of
their common transcription factors for every 1% divergence
of their amino acid sequences. In contrast, the set of
physical interaction partners of their protein products
changes much slower. The relative stability of downstream
functions of duplicated genes, is further corroborated by
their ability to substitute for each other in gene knockout
experiments.
Conclusion:
Apparently the upstream regulation of genes evolves much
more rapidly than the downstream functions of the
associated proteins. This is in accordance with a view
where it is regulatory changes that mainly drives
evolution. Any evolutionary model has eventually to account
for this disparity and we have here quantified its size on
a genome wide scale. In this context a very important open
question is to what extent our results for duplicated genes
within yeast (paralogs) carries over to homologeous
proteins in different species (orthologs).
LU TP 03-46
|