The thymus is the major primary immune tissue for the production of functional T lymphocytes in vertebrates. However, its evolutionary origin is unknown. It has recently been shown that the generation of local T cells also occurs in gut-associated lymphoid tissues (GALT). This suggests that the thymus and GALT have similar functions and that they might be evolutionarily related. We discuss the possibility that the thymus may have evolved from mucosa-associated lymphoid tissues (MALT) located in the gill region in early vertebrates. Various facts supporting this proposal are summarized.
No takes yet. Share an insight, caveat, or question.
Matsunaga et al. (2001) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: