caa a22 4500 445861223 CHVBK 20180317145443.0 cr unu---uuuuu 170323e20110801xx s 000 0 eng 10.1007/s00439-011-1016-7 doi (NATIONALLICENCE)springer-10.1007/s00439-011-1016-7 Migeon Barbara McKusick Nathans Institute of Genetic Medicine, The Johns Hopkins University, 459 Broadway Research Building, 733 N Broadway, 21205, Baltimore, MD, USA aut The single active X in human cells: evolutionary tinkering personified [Elektronische Daten] [Barbara Migeon] All mammals compensate for sex differences in numbers of X chromosomes by transcribing only a single X chromosome in cells of both sexes; however, they differ from one another in the details of the compensatory mechanisms. These species variations result from chance mutations, species differences in the staging of developmental events, and interactions between events that occur concurrently. Such variations, which have only recently been appreciated, do not interfere with the strategy of establishing a single active X, but they influence how it is carried out. In an overview of X dosage compensation in human cells, I point out the evolutionary variations. I also argue that it is the single active X that is chosen, rather than inactive ones. Further, I suggest that the initial events in the process—those that precede silencing of future inactive X chromosomes—include randomly choosing the future active X, most likely by repressing its XIST locus. Springer-Verlag, 2011 Human Genetics Springer-Verlag 130/2(2011-08-01), 281-293 0340-6717 130:2<281 2011 130 439 https://doi.org/10.1007/s00439-011-1016-7 text/html Onlinezugriff via DOI 1 review-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00439-011-1016-7 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Migeon Barbara McKusick Nathans Institute of Genetic Medicine, The Johns Hopkins University, 459 Broadway Research Building, 733 N Broadway, 21205, Baltimore, MD, USA aut NATIONALLICENCE 773 0- Human Genetics Springer-Verlag 130/2(2011-08-01), 281-293 0340-6717 130:2<281 2011 130 439 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer