This title provides an extremely helpful analysis of genes that may be associated with autoimmunity, and answers questions such as how these genes can be identified, and how the functions of the gene products can be elucidated. Incorporating data on disease-associated chromosomal loci that has been accumulated from inbred mice, the title: descibes how some susceptibility loci may be common to many diseases, whereas others are relatively disease specificdiscusses the importance of developing criteria for establishing the significance of these different categories of disease-associated loci.