title: Competent stripes for diverse positions of limbs/fins in gnathostome embryos.
abstract: Every vertebrate species has its own unique morphology adapted to a particular lifestyle and habitat. Limbs and fins are strikingly diversified in size, shape, and position along the body axis. This diversity in morphology suggests the existence of a variety of embryonic developmental programs. However, comparisons of various embryos suggest common mechanisms underlying limb/fin formation. Here, we report the existence of continuous stripes of competency for appendage formation along the dorsal midline and the lateral trunk of all of the major jawed vertebrate (gnathostome) groups. We also show that the developing fin buds of cartilaginous fish share a mechanism of anterior-posterior axis formation as well as an shh (sonic hedgehog) expression domain in the posterior bud. We hypothesize a continuous distribution of competent stripes that represents the common developmental program at the root of appendage formation in gnathostomes. This schema would have permitted subsequent divergence into various levels of limbs/fins in each animal group.
authors.affiliation: Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai 980-8578, Japan.
authors.forename: Sayuri
authors.initials: S
authors.lastname: Yonei-Tamura
authors.forename: Gembu
authors.initials: G
authors.lastname: Abe
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Anno
authors.forename: Miyuki
authors.initials: M
authors.lastname: Noro
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ide
authors.forename: Hideaki
authors.initials: H
authors.lastname: Aono
authors.forename: Ritsu
authors.initials: R
authors.lastname: Kuraishi
authors.forename: Noriko
authors.initials: N
authors.lastname: Osumi
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kuratani
authors.forename: Koji
authors.initials: K
authors.lastname: Tamura
mesh_terms: D000818:Animals; D005075:Biological Evolution; D004622:Embryo, Mammalian / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000378:metabolism; D005121:Extremities / Q000196:embryology*; D053823:Hedgehog Proteins / Q000235:genetics; D014714:Vertebrates / Q000196:embryology* / Q000235:genetics / Q000378:metabolism
chemical_list: D053823:Hedgehog Proteins