JERUSALEM, ISRAEL--Scientists think that epigenetic differences between modern humans and our archaic cousins may have made the difference in our survival. Epigenetics deals with how genes are turned on and off without modfying the DNA sequence. Liran Carmel, Eran Meshorer, and David Gokhman of Hebrew University, working with scientists from Germany and Spain, reconstructed the Neanderthal and Denisovan epigenomes, and compared them with the epigenome of modern humans. Science Daily reports that they found that gene activity had changed only in modern humans during our most recent evolution. Many of those changes occurred in the area of brain development, and are linked to diseases. Other changes were observed in the immune and cardiovascular systems, but the digestive system remained relatively unchanged.