[Histonet] Re: Barr body in Cell/culture - chromatin differentiation

[Robert Richmond]

Naira V. Margaryan, D.V.M., Ph.D. at Children's Memorial Research
Center in Chicago asks:

>>I need help with some technique. Do you know a method how to
recognize Barr body in Cell/culture which is mean we need a method to
stain chromatin to differentiate male from female?<<

There is an old (1960's) staining method for Barr bodies (sex
chromatin bodies) which was supposed to be fairly specific with a lot
of adjustment. But do cells in tissue culture have Barr bodies? The
Barr body is the inactivated X-chromosome. This inactivation (the Lyon
phenomenon, after Mary Lyon who described it in the 1960's) occurs
somewhere around day 15 of human embryogenesis. Not all human somatic
cells have identifiable Barr bodies (squamous epithelium and smooth
muscle do, liver and kidney don't).

I would think that a more specific method such as fluorescent in situ
hybridization (FISH) would be preferable.

Bob Richmond
Samurai Pathologist
Knoxville TN