Figure 4.

Presence of adjoining FISH signals in simultaneous hybridizations of Hsa1 homologous chromosomes between mammalian species. Adjoining bicolor signals were obtained on one chromosome of the target genome for the two Hsa1 homolog probes (differentially labeled), indicating a different breakpoint in the karyotypes of the two species examined. In only two experiments (squirrel on cat and pig on squirrel) did the two Hsa1 homologous probes produce only signals on different chromosomes of the target genome, indicating no evidence of a different breakpoint in the two species being compared. The reciprocal experiments (cat on squirrel and squirrel on pig) did show bicolor signals, suggesting evidence of different breakpoints between the two species pairs. Black boxes indicate results that were not reproducible between experiments.