H2BC21 and atrial fibrillation: Another group of 30 histone-related genes were upregulated in AF, including histone-lysine N-methyltransferase (n = 13), H2A (n = 4), H2B (n = 1), H3 (n = 3), H4 (n = 1), histone acetyltransferase (n = 2), histone chaperone (n = 1), set1/Ash2 histone methyltransferase complex (n = 1), histone RNA hairpin-binding protein (n = 1), histone acetyltransferase (n = 2), histone deacetylase (n = 1), indicating the potential chromatin regulation and DNA strand compacting during the oogenesis and cellular development of developing larvae contained within the reproductive tract of the adult female.