A recent article by Farkas and colleagues, published in Arthritis Research & Therapy, is from the laboratory of Dr Tibor Glant and his research team in Chicago, who have investigated in considerable depth the immunopathology of experimental arthritis induced by the major cartilage component proteoglycan aggrecan in an animal model that mimics many features of human rheumatoid arthritis and ankylosing spondylitis. This present report takes our understanding a significant step forward by questioning whether genetic drift in distinct colonies of the same inbred strains of mice has an impact on the parity between data published by different laboratories.