For example, the following genes were identified as being upregulated in AF: histone H1 (n = 2), H2A (n = 1), H2B (n = 4), H1/H5 (n = 1), H3.3 (n = 2), histone-binding protein Caf1 (n = 1), histone demethylation protein (n = 1), histone-lysine N-methyltransferase (n = 5), histone demethylase (n = 2), histone deacetylase (n = 1); whereas H3 (n = 2), histone-lysine N-methyltransferase (n = 13), histone acetyltransferase (n = 1), histone deacetylase (n = 1) were upregulated in eggs. The gene discussed is H2BC21; the disease is atrial fibrillation.