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Meiotic sex chromosome inactivation in the marsupial Monodelphis domestica
Author(s) -
Hornecker Jacey L.,
Samollow Paul B.,
Robinson Edward S.,
VandeBerg John L.,
McCarrey John R.
Publication year - 2007
Publication title -
genesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.093
H-Index - 110
eISSN - 1526-968X
pISSN - 1526-954X
DOI - 10.1002/dvg.20345
Subject(s) - biology , marsupial , monodelphis domestica , dosage compensation , x inactivation , x chromosome , somatic cell , genetics , chromosome , meiosis , zoology , gene
In eutherian mammals, the X and Y chromosomes undergo meiotic sex chromosome inactivation (MSCI) during spermatogenesis in males. However, following fertilization, both the paternally (Xp) and maternally (Xm) inherited X chromosomes are active in the inner cell mass of the female blastocyst, and then random inactivation of one X chromosome occurs in each cell, leading to a mosaic pattern of X‐chromosome activity in adult female tissues. In contrast, marsupial females show a nonrandom pattern of X chromosome activity, with repression of the Xp in all somatic tissues. Here, we show that MSCI also occurs during spermatogenesis in marsupials in a manner similar to, but more stable than that in eutherians. These findings support the suggestion that MSCI may have provided the basis for an early dosage compensation mechanism in mammals based solely on gametogenic events, and that random X‐chromosome inactivation during embryogenesis may have evolved subsequently in eutherian mammals. genesis 45:696–708, 2007. © 2007 Wiley‐Liss, Inc.