The relative intranuclear positions of Barr bodies in XXX non-transformed human fibroblasts.

The extent to which chromosomes exist in an ordered three-dimensional arrangement within the interphase nucleus remains unknown. As a means of tackling this issue we have developed simple statistical methods to test whether the positions of any intranuclear markers are mutually correlated. Applying these methods to non-transformed XXX human fibroblasts as a test case, we have examined the relative nuclear locations of the two Barr bodies in 2C cells of this type. Our results show that while individual Barr bodies have a highly non-random intranuclear distribution, segregating preferentially at the nuclear periphery in a plane parallel to the plane of cell growth (i.e., the substrate surface) and bisecting the nucleus, no evidence was found of any significant correlation between the positions of the two Barr bodies within a given nucleus.