Atypical Presence of Interstitial Telomeric Sequences in Thamnophilus Species (Passeriformes: Thamnophilidae)

This study revealed novel patterns of constitutive heterochromatin in T. ruficapillus and ITSs in both species, which have not been previously observed in Passeriformes. The correspondence between constitutive heterochromatin and ITSs in T. ruficapillus suggests that these sequences are composed of repetitive DNA highly similar to telomeric sequences and/or are remnants of pericentric inversions, whereas in T. caerulescens, other mechanisms seem to be involved. The differences in observed patterns highlight distinct chromosomal evolution between these species, emphasizing the diversity within the family Thamnophilidae and the genus Thamnophilus, in contrast to the conserved patterns typically observed in the class Aves.