Studies of X-chromosome inactivation in trisomies.
Previous studies of human triploidy have implicated the autosomes in the regulation of activity of X-linked genes. To determine if the influence of the extra autosomal set in triploids was attributable to a specific autosomal gene, we examined the pattern of DNA replication in females trisomic for 18 of the possible 22 autosomal trisomies. We find no evidence that a single gene or chromosome in triplicate can effect X-chromosome replication or activity. Our results suggest either that more than one locus in triplicate is required to maintain the activity of two X chromosomes, or that the influence of the extra autosomal set in enabling the activity of more than a single X chromosome is mediated indirectly, perhaps through the agency of increased nuclear size or changes in the cell cycle.
Wessex Regional Cytogenetics Unit, Salisbury General Hospital, UK.
P A
PA
Jacobs
B R
BR
Migeon
D002478:Cells, Cultured; D002877:Chromosomes, Human; D004261:DNA Replication; D004303:Dosage Compensation, Genetic; D005260:Female; D005333:Fetus / Q000201:enzymology / Q000648:ultrastructure; D005954:Glucosephosphate Dehydrogenase / Q000032:analysis; D006801:Humans; D008297:Male; D014314:Trisomy
D005954:Glucosephosphate Dehydrogenase