Heatmap of the RNA expression levels of ERVK retroviral genes ( n = 120) among three reproductive tissues and four other tissues. We applied a log10(count + 1) transformation to the normalized count for visualization. The black and gray cubes indicate significantly different levels of RNA expression between the ovary, testis, or primordial germ cells (PGC) in comparison with other organs (thresholds: log 2 (fold change) >= 1 with Benjamini-Hochberg adjusted p -value < 0.05).
