GoKawiilResearchers transplanted cells between embryos of a comb jelly (Mnemiopsis leidyi, right) and a starlet sea anemone (Nematostella vectensis, left).Credit: Paul R. Sterry/Nature Photographers Ltd/Alamy, Phil Degginger/Science Photo Library
More than a century ago, embryologist Hilde Mangold conducted a strange experiment that transformed biology.
As a PhD student in the 1920s, she moved a lump of cells from embryos of one newt species into another. The transplanted cells caused a secondary ‘body axis’ to form in the host embryo, complete with a nervous system and a precursor to the spine. Mangold showed that much of the secondary body axis developed from the recipient embryo tissues.
The discovery of an embryonic ‘organizer’ that orchestrates the formation of a body axis “established a whole new area of developmental biology”, says Stanislav Kremnyov, a developmental biologist at the Friedrich Schiller University Jena in Germany, who is now following in Mangold’s footsteps.
In a study published in Nature on 17 June1, Kremnyov and his colleagues report the discovery of an embryonic organizer in marine predators called comb jellies (Ctenophora) and their successful transplantation into sea anemones (Cnidaria) — which belong to an entirely different phylum — forming extra mouths and pharynxes.
Many scientists think comb jellies belong to the earliest branch of the animal family tree. Kremnyov and his colleagues argue the appearance of an organizer helped transform single-celled organisms into animals.
“I’m really excited to see this,” says Ulrich Technau, an evolutionary developmental biologist at the University of Vienna. But not all scientists are convinced by the claims.
Building a second body
Mangold died tragically in 1924 in a home gas explosion, but the discovery garnered her supervisor, Hans Spemann, the 1935 Nobel Prize in Physiology or Medicine.
Spemann’s laboratory became the centre of the developmental biology world, attracting leading scientists to probe the organizer and look for similar capabilities in other developing tissues.
... continue reading