X chromosomal inactivation is difficult enough to understand – there are now some more data on autosomal monoallelic expression (editorial & paper). Up to 10% of 4,000 genes in clonal cell lines were found to be monoallelic expressed (and up to 20% in some B cell clones). Only odorant and T cell receptors are selectively expressed while all other genes are thought to be randomly silenced.
I wonder how any transmission disequilibrium test makes sense if a variant is only transmitted to a silent chromosome? Possibly there are also epigenetic feedback loops where proteins can remodel chromatin and induce epigenetic marks ultimately silencing a chromosomal region. In any case, a fundamental paper, yea, yea!