PCR- and cytology-based validation of in silico–predicted, telomere-specialized elements. (A) Cartoon representation of our PCR-based validation of in silico–predicted gag and RT domains and head-to-tail orientation of candidate telomeric retrotransposons (and the previously validated HeT-A/TAHRE and TART). Primer orientation is represented above as cartoons in white and black. gag (arrowhead) and RT (rectangle) domains are represented by lighter or darker shades, respectively. PCR-validated partial gag and partial RT domains are represented as truncated symbols in D. takahashii and D. ananassae. (B) DNA-FISH or oligopainting with probes/paints cognate to HeT-A/TAHRE gag, TART, TARTAHRE, and TR2 on polytene chromosomes from representative species. HeT-A/TAHRE and TART from D. melanogaster serve as positive controls. All insets show telomere hybridization exclusively except TARTAHRE, which hybridized to both telomeric and nontelomeric locations (insets designated with an asterisk).
