Evidence for X-linkage and non-inactivation of steroid sulphatase locus in wood lemming

One of the two X chromosomes is inactivated in somatic cells of adult female mammals to compensate for unequal amounts of X-chromosomal genes in the two sexes 1 . Although the general validity of this concept is not in doubt, there is evidence that a segment of the distal short arm of the human X ch...

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Veröffentlicht in:Nature (London) 1982-04, Vol.296 (5859), p.766-767
Hauptverfasser: Ropers, H-H., Wiberg, U.
Format: Artikel
Sprache:eng
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Zusammenfassung:One of the two X chromosomes is inactivated in somatic cells of adult female mammals to compensate for unequal amounts of X-chromosomal genes in the two sexes 1 . Although the general validity of this concept is not in doubt, there is evidence that a segment of the distal short arm of the human X chromosome carrying the gene, or genes for the Xg blood group system, the steroid sulphatase (STS) locus 2,3 , and a gene controlling a serologically defined male-specific antigen 4,5 , is never inactivated. It is not known whether this non-inactivated segment is a special feature of the human X chromosome or whether it is a general feature of the ancestral, highly conserved, mammalian X chromosome 6 . In man the number of functional STS gene copies can be deduced from intracellular STS activity 7 . With this in mind we have investigated the number of active gene copies on the X chromosome of the wood lemming ( Myopus schistfcolor , Lilljeborg), by assaying STS in cultured cells of this species. We report here that STS activity is directly correlated to the number of X chromosomes and unrelated to the phenotypic sex. This suggests that in the wood lemming the STS gene is also X-linked and not subject to inactivation.
ISSN:0028-0836
1476-4687
DOI:10.1038/296766a0