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SUMMARY:The endocrine organs of Drosophila as new model to study extreme e
 volutionary divergence and epithelial to mesenchymal transitions during de
 velopment - James Castelli-Gair Hombría (Centro Andaluz de Biología del 
 Desarrollo\, Seville)
DTSTART:20131211T130000Z
DTEND:20131211T140000Z
UID:TALK48810@talks.cam.ac.uk
CONTACT:Jeremy Solly
DESCRIPTION:Segmented organisms present serially repeated homologous struc
 tures along the antero-posterior body axis. During development\, Hox prote
 ins control the segmental specialization of these structures transforming 
 their morphology and function. Despite this divergence\, the structures ca
 n still be clearly identified as homologous elements. We will present evid
 ence showing a situation of extreme divergence where the original ectoderm
 al structure has evolved into completely different structures: in one case
 \, two mesenchymal endocrine components of the ring gland\; and in the oth
 er\, the internal epithelial respiratory tracheal network.\n\nThe developm
 ent of trachea and endocrine organs initiates with the invagination of the
  polarized epithelial cells. The morphological divergence occurs shortly a
 fter invagination\, when activation of Snail in the endocrine primordia in
 duces an epithelial to mesenchymal transition. This is followed by the coa
 lescence of the corpora allata and prothoracic gland primordia that migrat
 e dorsally fusing\, first\, to the corpora cardiaca and\, later\, to the c
 ontralateral primordium in what becomes the ring gland. We show that the t
 rachea can be transformed into gland and vice versa demonstrating their ho
 mologous character.\n\nOur data are important because: (1) they uncover th
 e genetic and developmental mechanisms for ring gland morphogenesis and (2
 ) indicate that the respiratory tracheal organs and two main endocrine gla
 nds arose through a process of divergent evolution from an ectodermal repe
 ated structure that lead to extremely different morphological and function
 al organs.\n
LOCATION:Part II Lecture Theatre\, Department of Zoology
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