The X-inactivation centre. Genes are shown in bold, with the direction of transcription indicated by the arrow. P1 and P2 are the somatic Xist promoters, and P0 is a postulated Xist promoter in undifferentiated ES cells and early embryos. The deletions used to dissect the function of different elements in the Xic are shown as black lines and are described in Ref.
Blue bars indicate the regions that have been implicated in specific functions.
Effects on choice and counting have not so far been distinguished in the regions indicated by light bars. Please close this window to return to the main article. In such cases, please see the associated PDF file.