Formation of Vertebrate Appendages (Limbs and Fins)

  Limbs and fins, which are paired appendages of gnathostomes used for locomotion, are formed by shared developmental mechanisms, although the final morphologies of limbs and fins differ from each other (Yano and Tamura, 2013; Masselink et al, 2016). While limb bones are formed by endochondral ossification, fins comprise both endochondral bones and intramembranous bones. To understand the mechanisms of fin bone development and fin-to-limb evolution in gnathostomes, we are investigating pectoral fin formation in zebrafish (Danio rerio) (Yano et al, 2012).

We found a mutant fish whose pectoral fin lacked intramembranous bones. We are now seeking developmental mechanisms both of endochondral bones and intramembranous bones, that are derived from the lateral plate mesoderm (Shimada et al, 2013).

Refenrences:

Yano T and Tamura K (2013) "The making of differences between fins and limbs", Journal of Anatomy 222 (1), 100-113.

Masselink W, Cole NJ, Fenyes F, Berger S, Sonntag C, Wood A, Nguyen PD, Cohen N, Knopf F, Weidinger G, Hall TE and Currie PD (2016) "A somitic contribution to the apical ectodermal ridge is essential for fin formation", Nature doi:10.1038/nature18953

(Also read the post by Dr. Masselink, "How fish grew limbs and moved onto land" (2016))

Yano T, Abe G, Yokoyama H, Kawakami K and Tamura K (2012) "Mechanism of pectoral fin outgrowth in zebrafish development", Development 139 (16), 2916-2925.

Shimada A, Kawanishi T, Kaneko T, Yoshihara H, Yano T, Inohaya K, Kinoshita M, Kamei Y, Tamura K and Takeda H (2013) "Trunk exoskeleton in teleosts is mesodermal in origin", Nature Communications 4, 1639.