In decoding the DNA of a western lowland gorilla, scientists made a discovery that may surprise you: Humans and gorillas differ in just 1.75% of their DNA, making our genomes more similar than previously thought. That percentage actually drops to 1.37% when compared to chimpanzees, our closest living relatives—but 15% of the time, gorilla DNA is actually more like human DNA than chimp DNA is, the Los Angeles Times reports. That "tells us that there are individual genes for which, if you want to find the closest sequence to humans, you won't necessarily look at chimpanzees. In a few cases, you'll look at gorillas," says a geneticist.
It took a 60-strong team five years to sequence the 20,962 genes, which belong to Kamilah, a 34-year-old gorilla at the San Diego Zoo. Other lessons learned: Gorillas became a separate species 10 million years ago, about 4 million years before humans split off from chimps—a finding that jibes with fossil evidence, but stands in contrast to previous genetic evidence, which had indicated a more recent separation. "That's significant," says an anthropologist. "There's an argument about early hominids—are they really our ancestors? This helps settle that. It shows it's possible."