Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2017

Erindi/veggspjald / Talk/poster E87

The principles and predictability of transcriptional cooption, regulatory and compensatory evolution

Höfundar / Authors: Arnar Pálsson (1)

Starfsvettvangur / Affiliations: Institute of Biology, University of Iceland.

Kynnir / Presenter: Arnar Pálsson

Regulatory evolution is important for the emergence of new traits and adaptive evolution, because mutations in regulatory DNA are less pleiotropic than changes in coding sequences. The same genes have been deployed for multiple functions during evolution, by a process called transcriptional cooption. The functional properties of regulatory elements, e.g. short, degenerate motifs, for multiple activators and repressors, often diffuse regulatory elements, shape the evolution of regulatory sequences. For instance, stabilizing selection on transcription may explain the evolutionary turnover of transcription factor binding sites (TFBS) in enhancers. As new TFBS arise easily via mutation, it was proposed that any trans-factor can influence the transcription of (coopt) any gene in the genome.
Here we argue that regulatory evolution is more predictable, mainly because of tissue specific expression of regulatory factors. We use transcriptional cooption as an extreme scenario of regulatory evolution, to identify key predictions and hypotheses about how gene regulation evolves. First, the cooption of a gene „into“ a tissue will not be random. A coopted gene is more likely to be regulated by activators that are highly expressed in that tissue. Secondly, adaptive increase in expression of a gene in one tissue, may have regulatory side effects on its expression in other tissues. Third, similar regulatory side effects may be seen in the expression of linked genes.