HSP70 GENES ARE LINKED TO THE XENOPUS MAJOR HISTOCOMPATIBILITY COMPLEX

Some of the inducible forms of the heat shock protein 70 (Hsp70) gene family are encoded in the class m region of the major histocompatibili ty complex (MHC) of mammals. This study was undertaken to determine wh ether Hsp70 genes are linked to the MHC of Xenopus, an amphibian last sharing a common ancestor with mammals 300-350 million years ago. Segr egation analyses involving seven haplotypes demonstrated the linkage o f two or three inducible Hsp70 genes to the frog MHC. Another Hsp70 ge ne is not closely Linked to the MHC. We conclude that the physical ass ociation of MHC class I and class II genes with Hsp70 genes is ancient .