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The colonial urochordate Botryllus schlosseri : from stem cells and natural tissue transplantation to issues in evolutionary ecology
Author(s) -
Rinkevich Baruch
Publication year - 2002
Publication title -
bioessays
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.175
H-Index - 184
eISSN - 1521-1878
pISSN - 0265-9247
DOI - 10.1002/bies.10123
Subject(s) - allorecognition , biology , chordate , evolutionary biology , tunicate , zooid , sister group , chimera (genetics) , transplantation , model organism , stem cell , ecology , zoology , vertebrate , major histocompatibility complex , gene , phylogenetics , genetics , clade , medicine , surgery
The urochordates, whose stem groups may have included the direct predecessors of the chordate line, serve as an excellent model group of organisms for a variety of scientific disciplines. One taxon, the botryllid ascidian, has emerged as the model system for studying allorecognition; this work has concentrated on the cosmopolitan species Botryllus schlosseri . Studies analyzing self–nonself recognition in this colonial marine organism point to three levels of allorecognition, each associated with different outcomes. The first level controls natural allogeneic rejections and fusions, in which blood‐shared chimeras are formed. The second level leads to morphological resorption of partners within chimeras while the third allows the development of somatic and germ cell parasitic events. Recent studies on multi‐chimeric entities formed in allogeneic fusions reveal evolutionary links between allorecognition, stem cell biology and ecology. Thus, the Botryllus system generates perspectives from different biological disciplines to yield a unique life history portrait. BioEssays 24:730–740, 2002. © 2002 Wiley Periodicals, Inc.