Worm Breeder's Gazette 14(5): 45 (February 1, 1997)

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

Which is the first egg or chicken?

Hiroaki Kagawa, Chisaki Ishida, Yasuji Sakube

Molecular Biology, Department of Biology, Faculty of Science, Okayama University, Okayama Japan

     The order of egg and chicken is still in question as which is the
first gene duplication or tissue diversity.  Numbers of a gene or an
isoform will give a hint to solve the question.  We are studying on
function and structure of muscle genes in C. elegans.  Two of each
myosin heavy chain genes express in the pharynx and the body wall
muscles.  One paramyosin gene unc-15 express in both muscles.  The
troponin C gene tnc-1(pat-10) expressed in the body wall.  cDNA fragment
of tnc-1 hybridized to only one locus on the YAC library. From the
tropomyosin gene tmy-1(lev-11), one isoform express in the pharynx with
internal promoter and two isoforms express in the body wall with the
proximal promoter.  We confirmed that one of two isoforms expressed in
the body wall was alternatively spliced by using exon-specific lacZ
fusion plasmid.  Although we did not confirm the functional difference
of these two isoforms, this result suggests that gene diversity by
alternative splicing appeared before tissue differentiation.  Two
troponin I genes were also expressed in the body wall at the different
rate (Kuroda et al. unpublished).  Another cDNA sequence of troponin C
and more than two troponin I like sequences appeared in ACEDB.  These
results suggest also the idea that a gene duplication or amplification
is the first.  To know functional difference of multiple isoforms we are
asking when and how these isoforms can function in their
     Another important thing is the order to isolate mutants or to
isolate the gene.  We have historically known that isolating mutants is
the first.  Up to date reverse genetics is very popular even in the
laboratory of an expert in hunting mutants.  We have to change a mind or
shift the head for getting interesting answer.  To understanding
character of a gene undergraduate students may know you the sequence
information during isolating mutants in your experiment.  Sequence
information is not all but very powerful.  Touching the keyboard may be
the first before to handle a pipettman or plastic tube.  And you can
find function of a gene in the worm.  Finally you can know the order of
egg or the worm.
     Finally thinking science is much easier than doing science.