Fig. 9

Distribution of the Sgs3, Sgs7 and Sgs8 ortholog genes across the 24 studied Drosophila species and the most parsimonious scenario for gene gains and losses. Same legend as in Fig. 3. Black, red, pink, dark gray, dark purple and light purple arrows represent different copies of Sgs3 (respectively Sgs3b, Sgs3c, Sgs3d, Sgs3e, Sgs3f, Sgs3g). Dark blue and light blue arrows represent Sgs7 and Sgs8, respectively. Here we present one proposition for the attribution of the names Sgs7 and Sgs8 to the short Sgs glue genes, but the distinction between Sgs7 and Sgs8 can be unclear. Beige arrows indicate genes encoding short threonine-rich proteins. Light gray arrows indicate other adjacent neighboring genes. The Sgs3e coding sequence is located within Mob2 intron, but is represented near Mob2 for simplicity. Also note that for clarity a few of the neighboring genes and their corresponding orthologs were omitted in this figure. Arrows, minus and plus signs on the tree branches indicate, respectively, gene conversion, gene deletion and duplication events for Sgs3 in black and for Sgs7 and Sgs8 in blue. Crosses designate inversions. Double lines interrupting the genomic sequence indicate a gap of about 50 kb. Here we assumed that the most recent common ancestor of all represented species had two Sgs3 copies, Sgs3b and Sgs3e