Sex chromosome silencing in the marsupial male germ line

Satoshi H. Namekawa, John L. VandeBerg, John R. McCarrey, Jeannie T. Lee

    Research output: Contribution to journalArticle

    66 Scopus citations

    Abstract

    In marsupials, dosage compensation involves silencing of the father's X-chromosome. Because no XIST orthologue has been found, how imprinted X-inactivation occurs is unknown. In eutherians, the X is subject to meiotic sex chromosome inactivation (MSCI) in the paternal germ line and persists thereafter as postmeiotic sex chromatin (PMSC). One hypothesis proposes that the paternal X is inherited by the eutherian zygote as a preinactive X and raises the possibility of a similar process in the marsupial germ line. Here we demonstrate that MSCI and PMSC occur in the opossum. Surprisingly, silencing occurs before X-Y association. After MSCI, the X and Y fuse through a dense plate without obvious synapsis. Significantly, sex chromosome silencing continues after meiosis, with the opossum PMSC sharing features of eutherian PMSC. These results reveal a common gametogenic program in two diverse clades of mammals and support the idea that male germ-line silencing may have provided an ancestral form of mammalian dosage compensation.

    Original languageEnglish (US)
    Pages (from-to)9730-9735
    Number of pages6
    JournalProceedings of the National Academy of Sciences of the United States of America
    Volume104
    Issue number23
    DOIs
    StatePublished - Jun 5 2007

    Keywords

    • Meiosis
    • X-inactivation

    ASJC Scopus subject areas

    • General

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