Distribution of Chromatin Bodies in an XX/XY True Hermaphrodite. ∗

Abstract

The discovery by Barr and Bertram(l) of the chromatin body in the nerve cells of female cats set the stage for the development of nuclear sexing as an important clinical tool. However, the origin of the chromatin body is still not clear although a number of theories have been proposed to explain this feulgen-positive structure found in intermitotic nuclei of most female cells. Barr originally suggested that the chromatin body was due to somatic pairing of the heterochromatic parts of 2 X chromosomes. The observation in domestic chickens(2), in which the female is the heterogametic sex, that the female is chromatin positive and the male chromatin negative was contradictory to Barr's hypothesis, and also raised the possibility that the chromatin body might be a sex influenced character subject to extracelluar factors. Several observations on different intersexual conditions, however, indicate that the chromatin body is more likely cell autonomous. For example, in the testicular feminizing syndrome, where XY cells have been subjected to a female hormonal environment, the cells are chromatin negative. In the bovine free-martin a normal frequency of chromatin positive cells(3) has been demonstrated in neuronal tissue even though the animal had been extensively masculinized by its male cotwin. We have recently studied an hermaphrodite who is an XX/XY mosaic in a variety of tissues, and consequently offers a unique opportunity to test further the independence of the chromatin body formation. The chromatin body distribution in various tissues of this hermaphrodite is reported here.

Biopsies of various tissues of this true hermaphrodite(4) who was found to be an XX/XY mosaic resulting from a dual fertilization (5) were established in cultures by growing the cells in a mixture of medium 199 and 20% fetal calf serum.