Identification of triploidy by DA/DAPI staining of trophoblastic interphase nuclei.

Combined staining of non-cultured interphase nuclei from hydatidiform moles with distamycin A and DAPI resulted in the presence of specific stained interphase bodies. A mean number of six interphase bodies was observed in moles with a diploid karyotype and a mean number of nine interphase bodies was observed in triploid moles. It is concluded that the interphase bodies are primarily due to specific staining of the large heterochromatic areas on chromosomes 1, 9 and 16. The method may permit a rapid measurement of the ploidy of non-cultured hydatidiform moles and identify partial, triploid moles.