Comparison of the cardiopharyngeal gene regulatory networks in Corella inflata and Ciona robusta provides insights into developmental systems drift
Colgan, William; Leanza, Alexis
Mutations to gene regulatory networks drive evolutionary adaptation, but mutations
can also occur without phenotypic change. These neutral mutations instead lead to
developmental systems drift, evolutionary divergence in developmental systems
that does not alter the traits produced. Here we examine developmental systems
drift between two tunicate species, Corella inflata and Ciona robusta, in the
cardiopharyngeal gene regulatory network. Through cross-species assays and
functional enhancer analysis, we assess the amount of drift both in cis and in trans.
Here we show that the trans-regulatory architecture of the cardiopharyngeal gene
regulatory network is largely conserved between C. robusta and C. inflata, but cis-regulatory
elements within this network exhibit distinct levels of conservation.
These results suggest that the amount of drift cis-regulatory elements undergo is
not governed by overarching principles but rather by distinct structural and
functional constraints which are unique to each cis-regulatory element. We show
that the enhancer for FoxF, a key cardiopharyngeal gene, is highly conserved and
propose a model for the unique structural and functional constraints which this cis-regulatory
element experiences.
↧