Genes occupy a fixed and symmetrical position on sister chromatids.

摘要: Abstract A high-resolution fluorescence methodology for non-isotopic in situ hybridization was applied to determine the positions occupied by several single-copy genes, DNA sequences, and integrated viral genomes on sister chromatids. The lateral longitudinal mapping of probes performed prometaphase metaphase chromosomes. fixed position, exterior or median relation axis chromatids, observed a given probe, with symmetrical position double fluorescent spots. This appears be independent chromosome condensation stage from metaphase. These observations suggest an opposite helical-handedness conformation both chromatids mirror symmetry. They support model packaging recently proposed Boy de la Tour Laemmli. Moreover, our results indicate that last stages occur packing down coils without further coiling.