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

Abstract

SUMMARY: Previous 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 withMo^vbrandTanow demonstrate that the locus in fact lies close toTa. The data also provide genetic evidence which establish that the C3H/HeHXchromosome carries theXce^aallele of this gene and the JU/FaCt and C57BL/GoHXchromosomes carry theXce^ballele, 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 uponMo^vbrphenotypes 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.