Biology of the X chromosome
作者:
Stanley Gartler,
Michael Goldman,
期刊:
Current Opinion in Pediatrics
(OVID Available online 2001)
卷期:
Volume 13,
issue 4
页码: 340-345
ISSN:1040-8703
年代: 2001
出版商: OVID
数据来源: OVID
摘要:
The biology of the X chromosome is unique, as there are two Xs in females and only a single X in males, whereas the autosomes are present in duplicate in both sexes. The presence of only a single autosome, which can occur as a result of an error in meiotic segregation, is invariably an embryonic lethal event. Monosomy for the X chromosome is viable because of dosage compensation, a system found in all organisms with an X:Y form of sex determination, which brings about equality of expression of most X-linked genes in females and males. In mammals, the dosage compensation system involves silencing of most of the genes on one X chromosome; it is called X chromosome inactivation. In this review, we focus first on recent advances in our understanding of the molecular basis of the X inactivation mechanism. Then we consider an unusual feature of X inactivation, the mosaic nature of the female and subsequent exposure to somatic cell selection.
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