The polymorphic markers D1Mit100, D1Mit264, and D1Mit199 are near various immunoregulatory genes on chromosome 1. Mouse chromosome 1 is depicted with a horizontal line. Polymorphic markers associated with antibody development are shown above the line. The map positions along chromosome 1 (in cM) are shown below the line, as are genes found near these markers. Tir3b indicates trypanosomiasis infection response gene 3b; Sle8, systemic lupus erythematosus susceptibility gene 8; Ity2, immunity to Salmonella typhimurium 2 gene; Ptprc, protein tyrosine phosphatase, receptor type, C (also called CD45, B220).