The developing limb has been a very influential system for studying pattern formation in
vertebrates. In the past, classical embryological models have explained how patterned …

The gene encoding the secreted protein Sonic hedgehog (Shh) is expressed in the polarizing
region (or zone of polarizing activity), a small group of mesenchyme cells at the posterior …

The vertebrate limb continues to serve as an influential model of growth, morphogenesis
and pattern formation. With this Review, we aim to give an up-to-date picture of how a …

In the classical model of chick wing digit-patterning 1 , the polarizing region—a group of cells
at the posterior margin of the early bud—produces a morphogen gradient, now known to …

Three D-cyclin genes are expressed in the apical meristems of snapdragon (Antirrhinum
majus). The cyclin D1 andD3b genes are expressed throughout meristems, whereascyclin D3a …

The proposal that birds descended from theropod dinosaurs with digits 2, 3 and 4 was recently
given support by short-term fate maps, suggesting that the chick wing polarizing region—…

The developing limb is one of the first systems where it was proposed that a signalling gradient
is involved in pattern formation. This gradient for specifying positional information across …

How the positional values along the proximo-distal axis (stylopod-zeugopod-autopod) of the
limb are specified is intensely debated. Early work suggested that cells intrinsically change …

The developing limb is a major model for pattern formation in vertebrate embryos. Many of
the seminal discoveries of the mechanisms involved in patterning have been made using …

The tuberal hypothalamus controls life-supporting homeostatic processes, but despite its
fundamental role, the cells and signalling pathways that specify this unique region of the central …