VERTEBRATE MAJOR TRANSITION; FIN

The extreme diversity lies in fish paired fins, which are adapted to each ecological lifestyle such as stingray or flying fish. Batoid fish (skates and rays) have extremely wide pectoral fins along the anteroposterior axis compared with other fish, while teleosts possess a small endochondral domain with long rays in their fins. Apart from this spectacular diversity, fish fins are the evolutionary lineage leading to the tetrapod limb along with alterations to other body structures, which enabled fish to invade into land. Despite the accumulating morphological description, gaps in the fossil records have hold back our understanding of the underlying mechanisms.  An advent of new technologies, however, has make these problems within our reach. 

 
 

GENETIC UNDERPINNINGS OF "LANDING"

During the water-to-land transition, a number of body structures were modified and new structures evolved as can be seen such as in the skull, jaw, shoulder, lung, and appendages. Whereas these morphological changes are central to the evolution of tetrapods, little research has been done to discern their developmental bases and identify the contribution to the evolutionary mechanisms. Bridging functional genomics, embryology, and comparative anatomy, we answer long-standing and classical questions that could not be solved by either approach alone. 

Functional genomics approach

Leveraged by state-of-the-art genomic technology such as ATAC-, 4C-, or ChIP-sequencing, comparative genomics reveals the responsible loci for major morphological transitions. Identification of candidate loci, in turn, prompts us to test their functions by genetic manipulations.

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PhenotypIC analysis with nano CT scanner

An advent of new genetic tools enables us to modify target DNA loci. We investigate the phenotypes of genetically modfied fish with a CT scanner followed by segmentation of tissues and structures in 3D-analysis software. CT scanning comprehensively reveals morphological disparities between wildtype and mutant fish such as skeletal shape, innervation patterns, or even volume of muscles.

Along with conducting experiments in the lab, we perform experiments at Marine Biological Laboratory (MA) during summer time and also collaborate with American Museum of Natural History (NY) to understand the evolutionary mechanisms underlying vertebrate diversity.   

Publications