Expression analysis for new Sfps and their bioinformatically identified orthologs. RT-PCR was used to assay for expression of two Sfp genes, Sfp53E (top) and Sfp26Ad (middle), as well as a housekeeping control gene, RpL32 (bottom), which is expressed ubiquitously. Sfp53E is expressed exclusively in males of all three species assayed; female D. melanogaster and D. simulans show amplification of a larger than expected product, which could represent unspliced gene product. Sfp26Ad expression levels appeared variable between males of each species, and the pattern of expression is male-specific in D. simulans and D. yakuba and male-biased in D. melanogaster. Note that the D. yakuba Sfp53E and the D. melanogaster Sfp26Ad products are larger than the products from their orthologs in other species. This difference was caused by the use of distinct primer binding sites in each species; comparisons to the expected product sizes confirmed that proper splicing occurred in each of these two cases. Each image contains two ladder lanes with a 100-bp ladder; the smallest band in each lane is 100 bp. For additional RT-PCR data, see Supplemental Figure S2 and Supplemental Table S7.
