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Thesis defense : Rachel PAUL
| When |
Sep 03, 2019
from 01:30 to 04:00 |
|---|---|
| Where | Salle des Thèses |
| Contact Name | Rachel Paul |
| Attendees |
Jury members Prof. François KARCH Prof. Ingrid LOHMANN Dr. Muriel BOUBE Dr. Abderrahman KHILA Dr. Samir MERABET |
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On September 3rd,
Rachel (Merabet team)
will defend her thesis
HOX dose and the specification of flight appendages in insects
Insects display an astonishing array of diversity in flight appendage morphologies. One of the most striking modifications is the transformation of hindwings into highly reduced balancing structures called halteres. Work in Drosophila established that the specification of halteres is under the control of a single Hox gene, Ultrabithorax (Ubx). In contrast, the formation of forewings has been described to be Hox-independent. Here we reconsidered the role of Hox genes for flight appendage specification in Drosophila. We show that the Hox protein Antennapedia (Antp) is expressed at low level in specific cells of the wing blade primordium and required for the proper formation of the adult wing. Interestingly this role is dependent on the dose since Antp can specify a haltere instead of a wing upon high level of expression. Thus, the formation of divergent flight organs in Drosophila is not dependent on a specific Hox protein but on a specific Hox dose. In contrast, we observed that the Hox dose is similar between anterior and posterior flight appendage primordia in the four-wing insect species Bombyx mori. We propose that the specification of flight appendages is not a Hox free state and that variation in the Hox dose is a way to modify the wing size and shape, ultimately leading to a complete new balancing organ during insect evolution.On