Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. X (inactive)-specific transcript, also known as XIST, is a human gene. X Inactivation is an early developmental process in mammalian females that transcriptionally silences one of the pair of X chromosomes, thus providing dosage equivalence between males and females (see dosage compensation). THe process is regulated by several factors, including a region of chromosome X called the X inactivation center (XIC). THe XIST gene is expressed exclusively from the XIC of the inactive X chromosome. THe transcript is spliced but apparently does not encode a protein. THe transcript remains in the nucleus where it coats the inactive X chromosome. ALternatively spliced transcript variants have been identified, but their full length sequences have not been determined.