Abstract: The invention provides for nucleic acid sequences that are expressed in chondrocytes from any of the following developmental and disease stages: fetal, normal, mild osteoarthritic, moderate osteoarthritic, marked and osteoarthritic. The invention also relates to arrays and compositions comprising any combination of these nucleic acid sequences. The invention also provides for methods of using the arrays of the invention to diagnose osteoarthritis. The invention also provides for methods of identifying therapeutic agents that alter the level of expression of the nucleic acids of the invention or alter the anabolic level of a chondrocyte.