X chromosome inactivation in female embryos of a marsupial mouse (Antechinus stuartii).
Blastocysts and late gestation stages of the marsupial mouse, Antechinus stuartii, were examined cytologically and electrophoretically to investigate X chromosome activity during embryogenesis. A late replicating X chromosome was identified in the protoderm cells of female unilaminar blastocysts and in the cells of embryonic and extra-embryonic regions of older blastocysts. Sex chromatin bodies were also observed in female bilaminar and trilaminar blastocysts. The X linked enzyme alpha-galactosidase showed no evidence of paternal allele expression in the extra-embryonic region of bilaminar blastocysts or in the yolk sac and embryonic tissue of known heterozygotes. It is concluded that the late replicating X chromosome is paternal in origin and that unlike the laboratory mouse, X inactivation is not correlated with cell differentiation in Antechinus.
Johnston
P G
PG
School of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia.
Robinson
E S
ES
D000818:Animals; D001755:Blastocyst / Q000166:cytology; D002875:Chromosomes / Q000648:ultrastructure; D005260:Female; D007621:Karyotyping; D008394:Marsupialia / Q000235:genetics*; D008677:Metaphase; D009115:Muridae / Q000235:genetics; D012729:Sex Chromosome Aberrations; D013045:Species Specificity; D014960:X Chromosome; D000519:alpha-Galactosidase / Q000235:genetics
D000519:alpha-Galactosidase