Genome of Darwin’s “Living Fossil” Is Sequenced in Japan; Surprisingly, This Ancient Brachiopod Genome Is Found to Be Evolving Rapidly

A group of scientists from Okinawa Institute of Science and Technology Graduate University (OIST), Nagoya University, and the University of Tokyo have sequenced the first lingulid brachiopod genome, from Lingula anatina collected at Amami Island, Japan. (Note that this press release is also available in Japanese at (http://www.eurekalert.org/pub_releases_ml/2015-09/aaft-_1091715.php). Their paper was published online on September 18, 2015 in an open-access article in Nature Communications and presents the results of their analysis of over 34,000 genes comprising the L. anatina genome and shows that, despite Lingula's reputation as a "living fossil," its genome is actively evolving. The article is titled “The Lingula Genome Provides Insights into Brachiopod Evolution and the Origin of Phosphate Biomineralization.” Brachiopods are marine invertebrates with external shells and a stalk. They are often confused with molluscs; however, the resemblance is superficial. Unlike bivalves (clams and mussels) that have shells on the sides of their bodies, brachiopod shells are on the top and bottom. As a result, the plane of symmetry in a bivalve runs along the hinge; hence the two valves are mirror images of one another. In brachiopods the plane of symmetry is perpendicular to the hinge, so that the halves of the valves mirror each other. Brachiopods are one of the first known examples of animal biomineralization, a process whereby living organisms stiffen or harden tissues with minerals. The earliest discovered brachiopod fossils date back to the early Cambrian period, approximately 520 million years ago. Brachiopods quickly spread all over the world and dominated the seas during the Paleozoic era (542-251 million years ago) and, by virtue of their mineralized shells, left an abundance of fossils.
Login Or Register To Read Full Story