Early embryonic sexed Ceratitis capitata transcriptomes: in silico approaches to identify male biased/male determining genes.

The Mediterranean fruit fly Ceratitis capitata, or Medfly, is one of the most economically important agricultural pest insects in the world. The Medfly is a major pest affecting several key crops also in Europe, notably citrus fruits. It is a true fruit fly belongings to Tephritidae family, which contains many other important pest species. Sex determination genes could be usefully utilized to develop biotechnological tools for insect pest control, improving or substituting the main current biological control method, the Sterile Insect Tecnique (SIT). In C. capitata sex determination is controlled by a Y-linked male determining factor (M-factor) which influences, either directly or indirectly, the state of activity of the female determining master gene Cctraep (Cctra epigenetic) at 5-7 hours  of oviposition. We have developed a Medfly transgenic sexing strain which produces male-only progeny (95% efficiency) by transgene-mediated RNAi against the female determiner Cctraep gene. C. capitata XX males are fully fertile and could be successfully mated with XX females thus leading to the production of female-only (XX) progeny. Starting from two polyA+ RNA preparations, extracted from XX-only and XX-XY Medfly embryos at 6-8 hours from oviposition, we have defined two de novo transcriptome sets consisting respectively of 36427 (XX-XY, N50=2137) and 33765 (XX, N50=1972) assembled transcripts. In this poster we will outline the assembly testing pipeline, developed with a combination of different on-line and stand alone tools, and preliminary data on the in silico subtraction approach for the identification of male-biased genes/male-determining genes.