- For decades, scientists have known that DNA consists of four basic units — adenine, guanine, thymine and cytosine. Those four bases have been taught in science textbooks and have formed the basis of the growing knowledge regarding how genes code for life. Yet in recent history, scientists have expanded that list from four to six. Now, researchers have discovered the seventh and eighth bases of DNA. ( sciencedaily.com )#1461501from f5f15b6a, 10 months ago
