Analysis of the distribution pattern of sister chromatid exchanges in mitotic chromosomes of human T-lymphocytes.
Band locations of 344 sister chromatid exchanges (SCE), observed in chromosome preparations of peripheral T-lymphocyte cultures, were identified using a sequential Q-banding-sister chromatid differentiation staining protocol. A comparison between expected Poisson, expected negative binomial distributions and observed SCE patterns, revealed that the negative binomial distribution provided a better fit to our SCE data. The aggregated pattern of SCE distribution indicated that some bands were more prone to undergo these events. Genetic markers assigned to those bands recording a significant number of exchanges seemed to correspond with the transcriptionally active genes. The results confirm that SCE are induced at the early S-phase of the cell cycle involving the early replicating genes in these events. Potential applications of cytogenetic techniques employed in the present study are proposed.
Tositti
M L
ML
Departamento de Biología Celular, Universidad Simón Bolívar, Caracas, Venezuela.
Arvelo
F
F
D002871:Chromosome Banding; D002875:Chromosomes / Q000502:physiology; D006801:Humans; D008938:Mitosis / Q000235:genetics*; D016012:Poisson Distribution; D016196:S Phase; D012854:Sister Chromatid Exchange; D016008:Statistical Distributions; D013601:T-Lymphocytes / Q000166:cytology* / Q000648:ultrastructure; D014158:Transcription, Genetic