Analysis of the in vitro response of the Sapajus cay (Primates: Platyrrhini) genome to exposure to the radiomimetic bleomycin.

Bleomycin (BLM) is an antitumor and antibiotic agent widely used as a positive control in genotoxicity assays due to its ability to induce mutagenic effects across multiple organisms. In mammalian cells, BLM causes chromosomal damage, affecting both chromatids and chromosomes, including complex aberrations involving multiple chromosomes. A key question arises regarding the response to BLM-induced genotoxic stress in genomes with pronounced structural differences from the human genome, which may influence genomic stability. The Sapajus genus (Cebidae, Platyrrhini) is notable for its genome, which contains approximately 8-15 % heterochromatin-an unusually high proportion compared to other platyrrhines-and its remarkable conservation of euchromatic regions relative to the human karyotype. Given the critical role of heterochromatin in genome stability, understanding the DNA damage response mechanisms in heterochromatin-enriched genomes like that of Sapajus is essential to assessing their implications for chromosomal integrity and adaptation. In this study, peripheral blood lymphocytes from Sapajus cay were exposed to BLM, resulting in the induction of dicentrics, chromosomal and chromatid breaks. Notably, no complex chromosomal figures involving multiple chromosomes were observed. These findings provide valuable insights into the genomic stability of Sapajus cay in response to genotoxic stress, with potential implications for evolutionary and biomedical research.