... FGF gene complement among metazoans. In the cephalochordate amphioxus, which belongs to the chordate clade together with vertebrates and tunicates, we have previously shown that the main role of FGF during early development is the control of rostral somite formation. Inhibition of this signalling...

... across different organisms. Here, we apply a quantitative approach to learn how the notochord forms during the development of amphioxus: a basally branching chordate. Using a single-cell morphometrics pipeline, we quantify the geometries of thousands of amphioxus notochord cells, and project them...

.... Inhibiting embryonic cilia motility using methylcellulose (MC) blocks Hh protein enrichment on the right hand side and randomizes Dand5 expression and organ positioning along the L-R axis. These findings present a model showing that cilia movement is crucial for the symmetry breaks in amphioxus through...

...Yujun Liang; Delima Rathnayake; Shibo Huang; Anjalika Pathirana; Qiyu Xu; Shicui Zhang ABSTRACT Amphioxus, a cephalochordate, is an ideal animal in which to address questions about the evolution of regenerative ability and the mechanisms behind the invertebrate to vertebrate transition in chordates...

... expression. In this study, we report a novel regulatory mechanism for Hh in LR asymmetry development of amphioxus embryos. Our results revealed that Hh −/− embryos abolish Cerberus ( Cer ) transcription, with bilaterally symmetric expression of Nodal , Lefty and Pitx . In consequence, Hh −/− mutants...

...Stephanie Bertrand; Hector Escriva The phylogenetic position of amphioxus, together with its relatively simple and evolutionarily conserved morphology and genome structure, has led to its use as a model for studies of vertebrate evolution. In particular, the recent development of technical...

... Amphioxus Spemann organizer Embryonic axis Urbilateria Size scaling Evolution The evolution of animals, and specifically the relationships and lineages between extinct and extant species, is a central problem in biology ( Fig. 1 ). Related to it is a key question of evolutionary developmental...

... have suggested that the Nt/Trk system is a vertebrate innovation. We describe the isolation and characterisation of the amphioxus Trk receptor, AmphiTrk . Its ancestral link to vertebrate Trk receptors is supported by phylogenetic analysis and domain characterisation. The genomic structure of AmphiTrk...

... of acquisition of these roles by the Hairy subfamily, we have cloned and studied the expression pattern of the Hairy gene(s) in amphioxus. The cephalochordate amphioxus is widely believed to be the living invertebrate more closely related to vertebrates, the genome of which has not undergone the massive gene...

..., and agnathan to gnathostome. Isolation and comparison of amphioxus, lamprey and axolotl AP-2 reveals its extensive expansion in the vertebrate dorsal neural tube and pharyngeal arches, implying co-option of AP-2 genes by neural crest cells early in vertebrate evolution. Expression in non-neural ectoderm...

...Hector Escriva; Nicholas D. Holland; Hinrich Gronemeyer; Vincent Laudet; Linda Z. Holland Amphioxus, the closest living invertebrate relative of the vertebrates, has a notochord, segmental axial musculature, pharyngeal gill slits and dorsal hollow nerve cord, but lacks neural crest. In amphioxus...

...Kinya Yasui1; Shi-cui Zhang; Masanori Uemura; Hidetoshi Saiga ABSTRACT The long-standing question of how asymmetric development or asymmetric body structures in lancelets (amphioxus) are phylogenetically related to the body plan of other animals is still untouched. Three anterior structures...

... evolved from a single eye prototype, by a Pax-6 -dependent mechanism. Here we describe the characterization of a cephalochordate Pax-6 gene. The single amphioxus Pax-6 gene (AmphiPax-6) can produce several alternatively spliced transcripts, resulting in proteins with markedly different amino and carboxy...

... of AmphiEn , the engrailed gene of amphioxus, the closest living invertebrate relative of the vertebrates. In neurula embryos of amphioxus, AmphiEn is expressed along the anteroposterior axis as metameric stripes, each located in the posterior part of a nascent or newly formed segment. This pattern resembles...

...Nicholas D. Holland; Grace Panganiban; Erika L. Henyey; Linda Z. Holland ABSTRACT The dynamic expression patterns of the single amphioxus Distal-less homolog ( AmphiDll ) during development are consistent with successive roles of this gene in global regionalization of the ectoderm, establishment...

... respecified to a more posterior identity. As a corollary, neural crest migration into the pharyngeal arches is abnormal. We administered excess RA to developing amphioxus, the closest invertebrate relative of the vertebrates and thus a key organism for understanding evolution of the vertebrate body plan...

... Brachyury gene may be restricted to presumptive notochord. To understand the evolution of Brachyury genes and their developmental roles, we have searched for homologues in amphioxus, representing the third chordate subphylum and the probable closest relative of the vertebrates. We report the isolation...

...Peter W. H. Holland; Jordi Garcia-Fernàndez; Nic A. Williams; Arend Sidow ABSTRACT All vertebrates possess anatomical features not seen in their closest living relatives, the protochordates (tunicates and amphioxus). Some of these features depend on develop mental processes or cellular behaviours...

...Peter W. H. Holland; Linda Z. Holland; Nicola A. Williams; Nicholas D. Holland ABSTRACT The embryology of amphioxus has much in common with vertebrate embryology, reflecting a close phylogenetic relationship between the two groups. Amphioxus embryology is simpler in several key respects, however...