Elife. 2016 Aug 1;5. pii: e16087. doi: 10.7554/eLife.16087.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4969037/
- 1Department of Genetics and Evolution, University of Geneva, Geneva, Switzerland.
- 2Instituto Gulbenkian de Ciência, Lisbon, Portugal.
- 3School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
Abstract
Within land vertebrate species, snakes
display extreme variations in their body plan, characterized by the
absence of limbs and an elongated morphology. Such a particular
interpretation of the basic vertebrate body architecture has often been
associated with changes in the function or regulation of Hox genes.
Here, we use an interspecies comparative approach to investigate
different regulatory aspects at the snake HoxD locus. We report that, unlike in other vertebrates, snake
mesoderm-specific enhancers are mostly located within the HoxD cluster
itself rather than outside. In addition, despite both the absence of
limbs and an altered Hoxd gene regulation in external genitalia, the
limb-associated bimodal HoxD chromatin structure is maintained at the snake locus. Finally, we show that snake
and mouse orthologous enhancer sequences can display distinct
expression specificities. These results show that vertebrate
morphological evolution likely involved extensive reorganisation at Hox
loci, yet within a generally conserved regulatory framework.
KEYWORDS:
developmental biology; evolutionary biology; genomics; mouse; reptiles; snakes; squamata; stem cells
