Controlling elements in the mouse X-chromosome

Abstract

SUMMARYThe frequency and nature of the changes in ‘state’ of the mouse X-chromosome controlling element (inactivation centre) have been investigated on an inbred background. The results indicate with near-certainty that meiotic crossing over is the responsible mechanism and that the frequency of recombination between theT(1; X)Ctbreakpoint and the locus of the controlling element is approximately 3%. Maize-type ‘changes in state’ may occur under other experimental conditions. The data do not distinguish on which side of the autosomal insertion the element lies but when combined with observations of other investigators suggest that the location must be on theMo-Taside and very close toTa.