[Quantitative characteristics of heterochromatin regions in human metaphase chromosomes at different stages of ontogenesis].

The comparative study of C-heterochromatic regions has been provided for 1, 9, 16 and Y chromosomes of 30 human embryonal in vivo lymphocytes of 6-8 gestational weeks (obtained with medical abortions), on the one hand, and in vitro lymphocytes of 100 phenotypically normal newborns, on the other hand. According to the results the heterochromatic regions of 1, 9 and Y are significantly shorter in embryonal chromosomes as compared with lymphocytes of newborns.