Comparison of the sex determination gene cascades between Drosophilidae (Drosophila) , and Tephritidae (Ceratitis Anastrepha and Bactrocera), Muscidae (Musca) and Calliphoridae (Lucilia) families of Diptera. Tramat and Tra2mat indicate maternal Tra and Tra2 product. DsxF and DsxM stands for female and male Dsx protein, respectively. Though the maternal expression of gene tra-2 in Lucilia and the characterisation of this gene in Bactrocera have not been reported, both species are included in the scheme of this Figure because the analysis of tra in Bactrocera  and the analysis of tra and tra-2 in Lucilia  suggests their tra-2 genes have a similar function as in Ceratitis, Anastrepha and Musca. Scheme based on references 16, 17, 18, 23, 29, 30 and 36.