Frequency of evident Barr and "F" corpuscles in tetraploid Purkinje neurons.

A study was carried out with the purpose of establishing the frequency of female sex chromatin (Barr corpuscle) and male sex chromatin or ("F") fluorescent corpuscles in the Purkinje cerebellar neurones, that are tetraploid cells. Two Barr corpuscles were observed in 18 per cent of Purkinje cells in hematoxylin-eosin stained histological sections in five females and none in a similar number of male sex individuals. In the cerebellar smears stained according to Klinger's method, Barr corpuscles were observed in Purkinje cells in 30 per cent of females different to what was observed in male sex individuals. Smears stained with quinacrine dihydrochloride showed two "F" corpuscles in Purkinje cells of male individuals and only one fluorescent corpuscle in a lower percentage of glial cells and of the granule cell layer in this same material. "F" corpuscles were not observed in females. This study shows that in tetraploidy, as the case of Purkinje neurones, an X gonosome is expressed for each set of chromosomes in female individuals and an "F" corpuscle, corresponding to the Y gonosome of each chromosomic set is found in male sex individuals.