Genetics can reveal some truly bizarre facts that may not seem apparent on the outside, and a recent study examining a bizarre type of deep-sea worms is no exception. According to a report from Live Science, a new study shows that humans and worms shared a common ancestor, giving both species roughly 70 percent of the same genes.

The two species diverged from their common ancestor roughly 500 million years ago, and since then the acorn worm has become quite strange. The worms get their name from their acorn-shaped head, and are an unlikely distant cousin to cross paths with.

The study was led by Oleg Simakov from the Okinawa Institute of Science and Technology Graduate University in Japan. Simakov and his team analyzed the genome of two acorn worm species; one from the Pacific Ocean and one from the Atlantic Ocean.

Despite our vastly different appearances, humans and acorn worms were found to share roughly 14,000 genes altogether. The common ancestor between the bizarre acorn worm and our species is believed to have lived during the Cambrian explosion, when life began to grow increasingly diverse and a wide range of new features and capabilities emerged in the fossil record.

The worms belong to a group of animals called deuterostomes, and they share genes with closer relatives including sea stars, cephalopods, and all other vertebrates. Acorn worms are by far the oldest deuterostomes, emerging roughly 570 million years ago.

As the acorn worm and their relatives evolved, a number of species developed much more complex features and capabilities. Many of these slimy creatures’ innovations centered around feeding and breathing. Certain genes led to the development of gill slits, which allowed the worms to constantly take in fresh oxygen that was dissolved in the water. These slits allow water to be taken in, but also bypass the digestive system, allowing the acorn worm to breathe without swallowing water. This key development allowed more complex organisms to develop separate digestive and respiratory systems over time.

Despite the majority of our genes being the same, the 30 percent makes up the most noticeable differences between humans and acorn worms. The study, published in the journal Nature, can be found here.