Looking Far Afield . . .

Basic biology teaches us that genes on one of the X-chromosomes in women are not expressed in a clonal fashion. During the past decade, we learned that some rare autosomal genes are imprinted, and thus inactive, in a parent-of-origin–specific fashion, and that certain autosomal genes coding immunoglobulins and T-cell receptors are randomly expressed in somatic cells and their clones. These authors assessed allele-specific transcription of more than 4000 human genes in B-cell clonal cell lines. They found that more than 300 were subject to random monoallelic expression.