Evidence of non-random X chromosome activity in the mouse

Abstract

SUMMARY: X-linked modification of the heterozygous phenotypes of X-linked genes has been detected in the X chromosomes of several inbred strains of mice. The effect is similar to that of the alternative ‘states’ or alleles, of theX chromosome controlling element, Xce, identified in T(1; X)Ct X chromosomes. Tests on two such differing X chromosomes have indicated that the phenotypic modification results either from non-random inactivation of the two X chromosomes or from selection operating on the two cell populations differentiated by X-inactivation. The data provide evidence of non-random X chromosome activity in the somatic cells of the female mouse.