Received: by alpheratz.cpm.aca.mmu.ac.uk id PAA05955 (8.6.9/5.3[ref pg@gmsl.co.uk] for cpm.aca.mmu.ac.uk from fmb-majordomo@mmu.ac.uk); Mon, 13 May 2002 15:12:29 +0100 X-Originating-IP: [67.225.210.11] From: "Grant Callaghan" <grantc4@hotmail.com> To: memetics@mmu.ac.uk Subject: Memetic Influence on Evolution Date: Mon, 13 May 2002 07:06:08 -0700 Content-Type: text/plain; format=flowed Message-ID: <LAW2-F83pduG0QwLkD20000b21f@hotmail.com> X-OriginalArrivalTime: 13 May 2002 14:06:08.0695 (UTC) FILETIME=[546B9470:01C1FA87] Sender: fmb-majordomo@mmu.ac.uk Precedence: bulk Reply-To: memetics@mmu.ac.uk
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
PROFILE
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
alternatives.
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 (rickilewis@nasw.org) is a contributing editor.
She took the course "Embryos and Ancestors" with Rudy Raff and Tom Kaufman
in 1977.
References
1. E.C. Raff et al., "A novel ontogenetic pathway in hybrid embryos between
species with different modes of development," Development, 126:1937-45,
1999.
2. G. de Beer, Embryos and Ancestors, New York: Oxford University Press,
1958.
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.
Grant
_________________________________________________________________
Chat with friends online, try MSN Messenger: http://messenger.msn.com
===============================================================
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)
see: http://www.cpm.mmu.ac.uk/jom-emit
This archive was generated by hypermail 2b29 : Mon May 13 2002 - 15:24:15 BST