Controlling elements in the mouse: V. Linkage tests with X-linked genes

Abstract

SUMMARYPrevious studies have shown that the mouseXchromosomal locus,Xce, which causes non-randomXchromosome inactivation, is closely linked to the Is(X; 7)CtX-autosome translocation. This has placed it either nearTaon one side of the breakpoint or nearjpon the other. Linkage tests withMovbrandTanow demonstrate that the locus in fact lies close toTa. The data also provide genetic evidence which establish that the C3H/HeHXchromosome carries theXceaallele of this gene and the JU/FaCt and C57BL/GoHXchromosomes carry theXceballele, and further suggest that theX-linked modification of the heterozygous phenotypes ofX-linked genes observed by various other investigators are all attributable to differences at theXcelocus. Evidence of a maternal influence uponMovbrphenotypes is also presented. This appears to operate independently of theX-inactivation process, probably through an effect of differing levels of copper in the milk in early life upon the mutant coat colour in the young.