Comparison between STELA and Q-FISH. (A) Telomere lengths were determined in 4 cloned fibroblast lines by STELA and Q-FISH. The graph shows mean telomere length (± SEM) for both techniques. (B) Representative Q-FISH images of the allosomes in each clone analyzed. The X chromosome was identified with the addition of an X-specific centromeric PNA probe,³⁴  whereas the Y chromosome (BJ clone only) was identified by G-banding patterns.