Competent stripes for diverse positions of limbs/fins in gnathostome embryos.
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.
Yonei-Tamura
Sayuri
S
Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai 980-8578, Japan.
Abe
Gembu
G
Tanaka
Yoshio
Y
Anno
Hiromasa
H
Noro
Miyuki
M
Ide
Hiroyuki
H
Aono
Hideaki
H
Kuraishi
Ritsu
R
Osumi
Noriko
N
Kuratani
Shigeru
S
Tamura
Koji
K
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
D053823:Hedgehog Proteins