Deep phylogenomics of a tandem-repeat galectin regulating appendicular skeletal pattern formation

Bhat, Ramray and Chakraborty, Mahul and Glimm, Tilmann and Stewart, Thomas A and Newman, Stuart A (2016) Deep phylogenomics of a tandem-repeat galectin regulating appendicular skeletal pattern formation. In: BMC EVOLUTIONARY BIOLOGY, 16 .

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Abstract

Background: A multiscale network of two galectins Galectin-1 (Gal-1) and Galectin-8 (Gal-8) patterns the avian limb skeleton. Among vertebrates with paired appendages, chondrichthyan fins typically have one or more cartilage plates and many repeating parallel endoskeletal elements, actinopterygian fins have more varied patterns of nodules, bars and plates, while tetrapod limbs exhibit tandem arrays of few, proximodistally increasing numbers of elements. We applied a comparative genomic and protein evolution approach to understand the origin of the galectin patterning network. Having previously observed a phylogenetic constraint on Gal-1 structure across vertebrates, we asked whether evolutionary changes of Gal-8 could have critically contributed to the origin of the tetrapod pattern. Results: Translocations, duplications, and losses of Gal-8 genes in Actinopterygii established them in different genomic locations from those that the Sarcopterygii (including the tetrapods) share with chondrichthyans. The sarcopterygian Gal-8 genes acquired a potentially regulatory non-coding motif and underwent purifying selection. The actinopterygian Gal-8 genes, in contrast, did not acquire the non-coding motif and underwent positive selection. Conclusion: These observations interpreted through the lens of a reaction-diffusion-adhesion model based on avian experimental findings can account for the distinct endoskeletal patterns of cartilaginous, ray-finned, and lobe-finned fishes, and the stereotypical limb skeletons of tetrapods.

Item Type:	Journal Article
Publication:	BMC EVOLUTIONARY BIOLOGY
Additional Information:	Copy right for this article belongs to the BIOMED CENTRAL LTD, 236 GRAYS INN RD, FLOOR 6, LONDON WC1X 8HL, ENGLAND
Department/Centre:	Division of Biological Sciences > Molecular Reproduction, Development & Genetics
Date Deposited:	22 Oct 2016 07:24
Last Modified:	22 Oct 2016 07:24
URI:	http://eprints.iisc.ac.in/id/eprint/54934

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