The coelacanth is one of a small handful of living fishes that are probably closely related much more ancient, extinct creatures — including, the first fish to haul itself up onto land. Now scientists have sequenced its genes and are digging through the data in search of genetic clues to how fish and land-dwelling animals are connected to one another. Among the finds so far, a gene that seems to be connected to how animals grow placentas. Coelacanths don’t have placentas, but they do have eggs that hatch inside their own bodies.