Additional pathways that differ between Sod2+/+ and Sod2-/- erythroblasts include spliceosome, DNA repair and replication, purine and pyrimidine metabolism and gene sets associated with Huntington's and Parkinson's diseases (supplementary tables S2 and S3 list all pathways that differ between Sod2+/+ and Sod2-/- with a Z-score > ±2). Here, SOD2 is linked to Parkinson disease.