Re: webbing
HARRY R. ERWIN (herwin@osf1.gmu.edu)
21 Jul 1995 20:00:05 GMT
Alex Duncan (aduncan@mail.utexas.edu) wrote:
: In article <3ubsmn$2i9@portal.gmu.edu> HARRY R. ERWIN,
: herwin@osf1.gmu.edu writes:
: >The fruitfly geneticists have been getting into this area for a
: >couple of decades, and their genes are starting to match up to those found
: >in vertebrates (homeobox genes in particular). For example, the vertebrate
: >brain seems to be segmented, with the segments matching those found in the
: >front end of arthropods.
: I think I recall reading somewhere that the gene that controls
: segmentation of the arthropod abdomen is homologous to the gene that
: controls segmentation of the vertebrate neck. Anyone else hear this?
Pretty close. Actually the hind-brain. This has clarified the perception
that Amphioxus was brain-less. Not so--the vertebrate brain corresponds to
the front end of its nerve chord. This all seems to indicate that Romer's
speculations on the vertebrate body as a chimera of a tunicate barrel and
a neotenous larval element used for dispersal were fairly accurate.
--
Harry Erwin
Internet: herwin@gmu.edu
Home Page: http://osf1.gmu.edu/~herwin (try a couple of times)
PhD student in comp neurosci: "Glitches happen" & "Meaning is emotional"
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