Cis-regulatory architecture and the evolution of convergent phenotypes

FRANKEL N

Montevideo

Congreso; VI International Meeting of the Latin American Society for Developmental Biology; 2012

Latin American Society for Developmental Biology

Similar morphological, physiological, and behavioral features have evolved independently in different species, a pattern known as convergence. It is known that morphological convergence can occur through genetic changes in orthologous genes. In some cases of convergence, cis-regulatory changes generate parallel modifications in the expression patterns of orthologous genes. Our understanding of how changes in cis-regulatory regions contribute to convergence is hampered, usually, by a limited understanding of the global cis-regulatory structure of the evolving genes. We examined the genetic causes of a case of precise phenotypic convergence between Drosophila sechellia and Drosophila ezoana, two species that diverged 40 MYA. Previous studies revealed that changes in the cis-regulatory region of shavenbaby (svb, a transcript of the ovo locus) caused phenotypic evolution in the D. sechellia lineage. It has also been shown that the convergent phenotype of D. ezoana was likely caused by cis-regulatory evolution of svb. In this work we discovered that the large-scale cis-regulatory architecture of svb is mostly functionally conserved between these Drosophila species. Furthermore, we show that phenotypic convergence between D. sechellia and D. ezoana resulted from similar functional changes in orthologous enhancers of svb. Thus, convergence has resulted from multiple parallel non-coding changes within a functionally conserved cis-regulatory landscape.