{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,10]],"date-time":"2026-06-10T16:53:49Z","timestamp":1781110429454,"version":"3.54.1"},"reference-count":0,"publisher":"National Academy of Sciences","issue":"7","content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[1971,7]]},"abstract":"<jats:p>\n                    Expression of the two X-linked loci glucose-6-phosphate dehydrogenase (G6PD; EC 1.1.1.49) and hypoxanthine:guanine phosphoribosyltransferase (HGPRT; EC 2.4.2.8) was studied in single hair follicles of two females who were heterozygous for both of these genes (double heterozygotes). The coupling phase for these two loci was known to be\n                    <jats:italic>g6pd A<\/jats:italic>\n                    and\n                    <jats:italic>hyprt<\/jats:italic>\n                    <jats:sup>-<\/jats:sup>\n                    on the maternal X chromosome and\n                    <jats:italic>g6pd B<\/jats:italic>\n                    and\n                    <jats:italic>hgprt<\/jats:italic>\n                    <jats:sup>+<\/jats:sup>\n                    on the paternal X. Three phenotypic classes of hair follicles were observed in both double heterozygotes: G6pd A follicles with deficient HGPRT activity, G6pd B follicles with normal HGPRT activity, and G6pd AB follicles with intermediate HGPRT activity. These data directly demonstrate one of the predictions of the Lyon hypothesis that for two X-linked loci, those genes in\n                    <jats:italic>cis<\/jats:italic>\n                    position are turned on or off in a cell and its clone, while in\n                    <jats:italic>trans<\/jats:italic>\n                    only one gene or the other is expressed.\n                  <\/jats:p>","DOI":"10.1073\/pnas.68.7.1425","type":"journal-article","created":{"date-parts":[[2006,5,31]],"date-time":"2006-05-31T02:29:54Z","timestamp":1149042594000},"page":"1425-1427","update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":23,"title":["Expression of Two X-Linked Genes in Human Hair Follicles of Double Heterozygotes"],"prefix":"10.1073","volume":"68","author":[{"given":"Joseph L.","family":"Goldstein","sequence":"first","affiliation":[{"name":"Department of Medicine, University of Washington, Seattle, Wash. 98105"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"James F.","family":"Marks","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, The University of Texas Southwestern Medical School, Dallas, Texas 75235"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stanley M.","family":"Gartler","sequence":"additional","affiliation":[{"name":"Department of Medicine, University of Washington, Seattle, Wash. 98105"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[1971,7]]},"container-title":["Proceedings of the National Academy of Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pnas.org\/doi\/pdf\/10.1073\/pnas.68.7.1425","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,4,13]],"date-time":"2022-04-13T10:42:37Z","timestamp":1649846557000},"score":1,"resource":{"primary":{"URL":"https:\/\/pnas.org\/doi\/full\/10.1073\/pnas.68.7.1425"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1971,7]]},"references-count":0,"journal-issue":{"issue":"7","published-print":{"date-parts":[[1971,7]]}},"alternative-id":["10.1073\/pnas.68.7.1425"],"URL":"https:\/\/doi.org\/10.1073\/pnas.68.7.1425","relation":{},"ISSN":["0027-8424","1091-6490"],"issn-type":[{"value":"0027-8424","type":"print"},{"value":"1091-6490","type":"electronic"}],"subject":[],"published":{"date-parts":[[1971,7]]},"assertion":[{"value":"1971-07-01","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}