Identification of a Colonial Chordate Histocompatibility Gene

Abstract

A Gene for Early Acceptance One of the fundamental properties of the immune system is the ability to distinguish self- from nonself–histocompatibility. To gain insight into the evolution and molecular basis of histocompatibility, Voskoboynik et al. (p. 384 ) sought to determine the genetic basis for a natural transplantation reaction that occurs in Botryllus schlosseri , a colonial urochordate. Compatibility allows vascular fusion among individuals, whereas incompatibility results in an inflammatory rejection response. A single gene determined the outcome of the reaction. Like histocompatibility genes in higher organisms, this gene is polymorphic and is expressed in the tissues that participate in the transplantation reaction.