RésuméThe basket clams Corbicula spp. are among the most well-known and extensively studied freshwater bivalves. First, they constitute an important food resource in Asia, reaching an annual output of a dozen thousands tons, and being of great economic significance. Second, their extraordinary range expansion in the past 100 years is undoubtedly the first reason why the genus has been studied recently. Many researchers recognized the importance of this taxon to investigate biological invasions, the factors underlying invasiveness and impacts of invaders. Third, Corbicula clams are also flagship organisms when it comes to ecotoxicology; their efficient bioaccumulation confers them excellent bioindicator features. Finally many pharmacological properties (antioxidant, antitumoral, hepato-protective...) are attributed to these clams.
Nevertheless none of the previously cited properties of Corbicula is the focus of the present study. The genus is indeed the only known animal taxon in which an odd and very rare reproductive mode is highly widespread and successful. This mode of reproduction is androgenesis, or “all-male asexuality”. Androgenesis is a strict paternal inheritance, since the offspring only inherit the nuclear genome of their father.
The main goal of the present thesis was to broaden our understanding of androgenesis and its evolution in the genus Corbicula. How and where did androgenesis originate and how is it maintained in Corbicula? What are the cytological mechanisms underlying the spermatogenesis process of androgenesis? How has androgenesis shaped Corbicula phylogeny and muddled its taxonomy? These are the questions we asked ourselves all along these last four years and to which I brought an answer.
|la date de réponse||19 oct. 2015|
|Superviseur||Karine Van Doninck (Promoteur), Patrick KESTEMONT (Président), Serge Aron (Jury), Thierry Backeljau (Jury), Jean-François Flot (Jury) & Clothilde Heude (Jury)|