Equality for X Chromosomes

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Science  08 Dec 1995:
Vol. 270, Issue 5242, pp. 1607-1610
DOI: 10.1126/science.270.5242.1607


In many species, females possess two X chromosomes and males have one X chromosome. This difference is critical for the initial determination of sex. However, the X encodes many functions required equally in males and females; thus, X chromosome expression must be adjusted to compensate for the difference in dosage between the sexes. Distinct dosage compensation mechanisms have evolved in different species. A common theme in the Drosophila melanogaster and Caenorhabditis elegans systems is that a subtle alteration of chromatin structure may impose this modest, but vital adjustment of the X chromosome transcription level.

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