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 …

The colorful phenotypes of birds have long provided rich source material for evolutionary
biologists. Avian plumage, beaks, skin, and eggs—which exhibit a stunning range of cryptic …

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 …

Clubfoot or talipes equinovarus (TEV) is an inborn three-dimensional deformity of leg, ankle
and foot. It results from structural defects of several tissues of foot and lower leg leading to …

Tissue patterning is the result of complex interactions between transcriptional programs and
various mechanical cues that modulate cell behaviour and drive morphogenesis. Vertebrate …

The periodic color motifs such as the spots or stripes that adorn the coat of vertebrates have
served as emblematic systems in empirical and theoretical studies of pattern formation …

Abstract Among John Saunders' many seminal contributions to developmental biology, his
discovery of the limb 'zone of polarizing activity'(ZPA) is arguably one of the most memorable …

The chick embryo has a long history in investigations of vertebrate limb development
because of the ease with which its limbs can be experimentally manipulated. Early studies …

A fundamental question is how proliferation and growth are timed during embryogenesis.
Although it has been suggested that the cell cycle could be a timer, the underlying …

Classical tissue recombination experiments performed in the chick embryo provide evidence
that signals operating during early limb development specify the position and identity of …