Branchiostoma lanceolatum

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, recent development of technical approaches, as well as access to the complete amphioxus genome sequence, for the Mediterranean amphioxus, Branchiostoma lanceolatum has provided the community with tools with which to study the invertebrate-chordate to vertebrate transition (Bertrand & Escriva, 2011).

Mediterranean Sea and North-East Atlantic

• Controlled spawning induction
• Transparent embryos
• Micromanipulation techniques available allowing functional approaches in classical embryology and developmental biology

Studies with different amphioxus species have helped answer questions about the evolution of the chordate genome, and particularly the evolution of the Hox cluster structure and cis-regulatory elements, the evolution of the control of axial patterning in chordates, and the appearance of vertebrate-specific structures such as the head.

• Assembled and annotated genome sequence (550 MB) and many transcriptome resources soon publically available
• Epigenomic resources including Chip-seq, ATAC-seq, Methylome, CAGE-seq, and 4C for a panel of transcription factors are available for several developmental stages

Due to a short spawning period (May-July), in vivo experiments are restricted to a short period only. Their life cycle is also relatively long, about 2 years to reach adulthood, and no knockdown techniques are available (no morpholinos, RNAi or siRNA).

• Bertrand S. & Escriva H. (2011) Evolutionary crossroads in developmental biology: amphioxus. Development 138: 4819-30