Despite their ubiquity in the world’s oceans, the evolutionary origin of the arrow worm has long baffled biologists – Charles Darwin himself noted their “obscurity of affinities” in 1844. Notably, the worm has characteristics of both protostomes, which include arthropods, mollusks, and annelids, and deuterostomes, which covers all animals with a spinal cord. These two groups are thought to have diverged from a common ancestor in the Ediacaran era, about 600 million years ago.

But now, researchers from University College London (UCL), the Goto Laboratory at Mie University, and the Okinawa Institute of Science and Technology (OIST) have finally pinned down the genomic, epigenomic, and cellular landscape of this enigmatic animal in a study published in Nature. As a planktonic animal, they are almost impossible to culture in the lab – save for one species, Paraspadella gotoi, named in honor of Professor Taichiri Goto, who is the first to successfully breed chaetognaths.

Reproductive timing matters when it comes to aging and age-related disease.  In a study now online at eLife¸ researchers determine that girls who begin menstruation before the age of 11 or women who give birth before the age of 21 have double the risk of developing type 2 diabetes, heart failure and obesity and quadruple the risk of developing severe metabolic disorders. The study also reveals that later puberty and childbirth are genetically associated with longer lifespan, lower frailty, slower epigenetic aging and reduced risk of age-related diseases, including type 2 diabetes and Alzheimer’s.