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SUMMARY:Speciation and genomic diversity of Drosophila species: based on m
 icroarray and genome analyses - Dr. Atsushi Ogura\, Department of developm
 ental biology and neuroscience\, Tohoku University\, Sendai\, Japan
DTSTART:20061116T160000Z
DTEND:20061116T170000Z
UID:TALK5940@talks.cam.ac.uk
CONTACT:Gos Micklem
DESCRIPTION:Diversification of species is one of the oldest issues in biol
 ogy dating back to Darwin\, and many biologists then have tried to gain in
 sight through population genetics and molecular biology.  We investigated 
 two\ntopics to understand speciation of Drosophila\, which are sex-ratio d
 istortion (SR) and genetic diversification at genomic level.  SR is one\no
 f the forms of non-Mendelian segregation possibly underlying reproductive 
 isolation and speciation in some species of Drosophila.  To investigate th
 e mechanism of suppression in two novel cases of SR in D.\nsimulans\, we c
 onducted microarray experiments with the too much yin (Tmy) and not much y
 ang (Nmy) suppressors.  We found 61 genes that are differentially expresse
 d in mutants compared with wild type. We then compared the sequence struct
 ures of Tmy and Nmy against the whole\nDrosophila genome\, and found a pos
 sible regulatory element that may\nregulate some of these 61 genes.  This 
 result estimates the gene\nexpression network that underlies SR suppressio
 n in Drosophila.  For the\nanalyses of genomic diversification in Drosophi
 la\, we investigated\ngenomic changes with speciation of seven Drosophila 
 species and discuss\nhow diversification has occurred through these change
 s.  From the\ngenomic data of seven Drosophila species\, we identified 991
 6 gene\nclusters that are shared by at least two species.  Identifying\nor
 thologous genes by means of phylogenetic analyses of these clusters\,\nwe 
 examined lineage specific expansions (LSE)\, rapidly evolved genes\n(RE)\,
  and loss of genes (GL) in each species.  One interesting finding\nis that
 \, in the LSE\, there are many genes corresponding to gene ontology\ncateg
 ories "response to stimulus" or "morphogenesis"\, which might play a\nrole
  in adaptation to a new or changing environment.  These analyses\nsuggest 
 that Drosophila species have complex mechanisms of genomic\ndiversificatio
 n perhaps reflecting adaptation to changes in their\nenvironment.\n
LOCATION:Part II Room\, Department of Genetics
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