Memetic Influence on Evolution

From: Grant Callaghan (
Date: Mon May 13 2002 - 15:06:08 BST

  • Next message: Scott Chase: "Re: Memetic Influence on Evolution"

    Received: by id PAA05955 (8.6.9/5.3[ref] for from; Mon, 13 May 2002 15:12:29 +0100
    X-Originating-IP: []
    From: "Grant Callaghan" <>
    Subject: Memetic Influence on Evolution
    Date: Mon, 13 May 2002 07:06:08 -0700
    Content-Type: text/plain; format=flowed
    Message-ID: <>
    X-OriginalArrivalTime: 13 May 2002 14:06:08.0695 (UTC) FILETIME=[546B9470:01C1FA87]
    Precedence: bulk

    The following story illustrates the coming influence of memetics on genetic
    evolution. For a view of what we might do about it, read Francis Fukuyama's
    Our Posthuman Future: Consequences of the Biotechnology Revolution.

    The Scientist 16[10]:68, May. 13, 2002

    Rudolf Raff
    At the crossroads of evolution, development,
    and genetics

    By Ricki Lewis

    Courtesy of Rudolf Raff

    If a visitor to Earth were to try to assess life's diversity by touring
    terrestrial biology laboratories, he, she, or it might conclude that the
    planet is overrun with fruit flies, mice, small plants, tiny transparent
    worms, and a few types of single-celled inhabitants. That skewed view might
    be why it's taken more than a century for the field called evo-devo today to
    have taken off.
    It's also why Indiana University distinguished professor Rudolf (Rudy) Raff
    collects sea urchins from the Australian coast instead of ordering mice from
    the Jackson Laboratory or flies from the Drosophila stock center right next
    door. He's been doing so since 1985, along with wife and
    researcher-in-her-own-right Beth, who takes an annual "maggot sabbatical" to
    join him.

    In February, Rudy Raff was one of eight scientists to receive the Medal of
    Alexander Kowalevsky from the Council of the St. Petersburg Society of
    Naturalists in Russia. Due to intervening wars, revolutions, and national
    dissolutions, the medal had not been awarded again since its creation in
    1910. Scott Gilbert, professor of biology at Swarthmore College and another
    founder of evo-devo, explains why Raff received the honor: "Rudy is trying
    to create a new synthesis of the entire field of biology, nothing less, by
    reuniting evolutionary biology with developmental biology."

    Before evo-devo had a name, Raff organized symposia that brought together
    the contributing life sciences in a new way. "At one of these meetings, I
    heard an animated conversation between a postdoc in developmental biology
    and an eminent arthropod paleontologist. Both were investigating the origins
    of the insect jaw," Gilbert recalls. Raff was the first chair of evo-devo
    for the Society for Integrative and Comparative Biology, and he established
    the first journal. "Rudy has gotten the researchers in evolutionary and
    developmental biology to speak to each other, he's given us a manual as to
    how to productively have these conversations, he has framed the problems for
    the field, and he has provided a specific forum for discussions in this
    area," Gilbert adds.

    Back in the lab, Raff concentrates on echinoderms, the invertebrates with a
    characteristic five-part symmetry. He sees two ways to choose one's
    experimental organism. "You can start with a model and study its relatives.
    Or, you can go out and find species with appealing properties. I find
    organisms such as sea urchins and starfish that are interesting and don't
    worry if they are suitable models."

    By generalizing from "little collections of organisms," biologists have
    missed many clues to evolution, Raff contends. A broader view of life also
    entails considering development right from the beginning. "Nature has
    alternate developmental modes. All sea urchins, all frogs, don't necessarily
    develop in the canonical way. This is wonderful material to reveal
    evolution," he exclaims. "How does nature make essentially the same organism
    through a completely different developmental pathway? How fast did the new
    way arise? How many genes did it require, and what were the selective
    pressures?" It all comes back to body plans, he says, and biologists needn't
    rely on Cambrian fossils for answers. "We can look at related modern
    organisms that had big changes in structure over time. With this approach,
    I've got my time machine."

    Two species of sea urchins that last shared an ancestor 10 million years ago
    have provided that time machine for Raff. One species develops through a
    typical feeding larva stage; the other hatches directly into a juvenile
    adult. Yet when Raff's group created a hybrid, the animal was more than the
    sum of its parts—it had the larval feeding apparatus, yet also
    characteristics of more ancient echinoderms not seen in either parent.1 Raff
    speculates on what might have happened: "I think the first evolutionary step
    was freedom from the need to feed. From there, the animal could drop the
    feeding features, then develop others, like highly rapid development."

    Raff came to science as many biologists do, collecting fossils as a young
    child. Another powerful influence was Gavin de Beer's book Embryos and
    Ancestors,2 which Raff read in his "spare time" as a grad student in
    biochemistry at Duke University, which meant while doing laundry. De Beer
    wrote that evolution occurs through changes in timing of key developmental
    events. That paradigm seemed too constraining to Raff, but back then tools
    such as molecular phylogenetics did not exist to experimentally investigate

    Ironically, timing would become a recurring theme in Raff's career. The
    guiding principles of what would become evo-devo began to coalesce in his
    mind long before he could categorize his thoughts. By the mid-1970s, his
    ideas had gelled sufficiently that he and distinguished professor Thomas
    Kaufman, who investigates homeotic mutations in Drosophila and other
    arthropods, offered a graduate course called "Embryos and Ancestors," one of
    the first official retrospective evo-devo courses. In 1983, the pair
    published an early book in the field,3 but it proved too visionary. By 1996,
    when Raff published The Shape of Life, the time had come.4 One of many rave
    reviews called it "arguably one of the most important books of the decade in
    evolutionary biology."5

    Clearly uncomfortable being called a founder of a field that many have
    built, Raff—in the introduction to The Shape of Life—traces evo-devo's
    origins to Charles Darwin, German evolutionary biologist Ernst Haeckel, and
    many others.

    Ricki Lewis ( is a contributing editor.
    She took the course "Embryos and Ancestors" with Rudy Raff and Tom Kaufman
    in 1977.

    1. E.C. Raff et al., "A novel ontogenetic pathway in hybrid embryos between
    species with different modes of development," Development, 126:1937-45,

    2. G. de Beer, Embryos and Ancestors, New York: Oxford University Press,

    3. R.A. Raff, T.C. Kaufman, Embryos, Genes, and Evolution, New York:
    MacMillan, 1983.

    4. R.A. Raff, The Shape of Life, Chicago: University of Chicago Press, 1996.

    5. M.L. McKinney, "Understanding evolution: The next step," Science,
    273:1347, 1996.


    Chat with friends online, try MSN Messenger:

    This was distributed via the memetics list associated with the
    Journal of Memetics - Evolutionary Models of Information Transmission
    For information about the journal and the list (e.g. unsubscribing)

    This archive was generated by hypermail 2b29 : Mon May 13 2002 - 15:24:15 BST