BACKGROUND Classic embryological studies showed that diffusible factors (morphogens)
influence cell fate during dorsal-ventral (DV) axis patterning. Subsequently, mathematical …

How animals establish and pattern the primary body axis is one of the most fundamental
problems in biology. Data from diverse deuterostomes (frog, fish, mouse, and amphioxus) …

Abstract Lancelets ('amphioxus') are the modern survivors of an ancient chordate lineage,
with a fossil record dating back to the Cambrian period. Here we describe the structure and …

Charles Darwin appreciated the conceptual difficulty in accepting that an organ as wonderful
as the vertebrate eye could have evolved through natural selection. He reasoned that if …

Cephalochordates, urochordates, and vertebrates evolved from a common ancestor over
520 million years ago. To improve our understanding of chordate evolution and the origin of …

Wnt genes are important regulators of embryogenesis and cell differentiation in vertebrates
and insects. New data revealed by comparative genomics have now shown that members of …

Planarian flatworms can regenerate heads at anterior-facing wounds and tails at posterior-
facing wounds throughout the body. How this regeneration polarity is specified has been a …

The regulation of body axis specification in the common ancestor of bilaterians remains
controversial. BMP signaling appears to be an ancient program for patterning the secondary …

Most animals evolved from a common ancestor, Urbilateria, which already had in place the
developmental genetic networks for shaping body plans. Comparative genomics has …

TGF-β family ligands function in inducing and patterning many tissues of the early vertebrate
embryonic body plan. Nodal signaling is essential for the specification of mesendodermal …