Joined: May 2002
here's a good recent discussion of the implications of the finding of a proto-immunoglobulin in amphioxus, branchiostoma floridae:
(in nature immunology)
The origins of the adaptive immune system: whatever next?
|The discovery of a V-like Ig multigene family in the protochordate amphioxus provides new insights into the evolution of the adaptive immune response.|
Diversity is at the same time the essential product of evolution and the essential substrate on which it must act. Although diversity can be the result of many different pressures and mechanisms, it is particularly evident and rapidly evolving in the responses of hosts to pathogens and parasites. Of the many defense systems described from the simplest single-celled bacteria to the most complicated plants and animals, none has been more intensively studied than the mammalian adaptive immune system. It has only recently become apparent that the adaptive immune system arose in the jawed vertebrates, but little is known about the deeper origins of this system or the relationship with other defense systems in nonvertebrate organisms. In this issue of Nature Immunology, Litman and colleagues describe a set of newly identified sequences from the protochordate amphioxus (Fig. 1), which make up a diversified multigene family and could hold some clues to the emergence of the adaptive immune system.
for the rest of the article, follow the link at the top.