[In situ hybridization of chorionic villi cells]

Two cloned alpha fragments of satellite repetitive DNA sequences were used to modify the method of DNA hybridization in situ (HIS) for tissue cells of human chorionic villi. Techniques for the cells of short-term lymphocytic cultures were used to optimize the conditions of HIS in chorionic villi cells with regard to a more specific localization of cloned repetitive DNA sequences in the target homologous chromosomes. A total of 262 specimens were prepared using the HIS method. As the results show, both cloned fragments are well applicable for routine cytogenic practice, the fragment p YAM 10-40 for the number of chromosomes, and fragment p YAM 9-72 for chromosomes 18.