Amphioxus possesses clear segmented, myomeric musculature that is an important point of comparison to vertebrate muscles for understanding the origins and evolution of vertebrate somatic musculature. The whole genome duplications that occurred at the origins of vertebrates (the 2R hypothesis) and then again early in teleost evolution (the 3R hypothesis) had important impacts on the composition of all sorts of gene networks, including those controlling muscle development and function. Amphioxus provides an excellent outgroup comparison to the vertebrates, such as the conventional models in developmental biology (e.g. mouse, chick, zebrafish) as well as important sources of food (e.g. salmon, carp), which will enable the impacts of these large-scale duplication events on muscle gene networks to be deduced.
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