Fig. 4.

Evolutionary histories of goddard and saturn. (A) Copy numbers and inferred evolutionary histories of goddard and saturn across the Drosophila genus. Colored circles next to each species/group on the phylogeny indicate the number of copies of each gene identified in that taxon. Gray circles indicate putative, unannotated orthologs of goddard discovered based on syntenic location. (B) Goddard is located within an intron of the omega (ome) gene and is found in the same orientation in all species that have the gene. (C) Saturn gene structure in different groups of Drosophila species. Saturn is located within an intron of the nuclear fallout (nuf) gene in the melanogaster group and in D. virilis and mojavensis, though the orientation of saturn has been reversed in the latter species. Searches of the syntenic region in the obscura group and D. willistoni did not reveal any plausible saturn gene, and D. grimshawi had only partial remnants. In D. virilis and mojavensis, a saturn paralog is found in a large intron of the ortholog of the D. melanogaster gene, AstA-R1. Branch lengths in panel A and gene models in panels B and C are not to scale.