title: X-inactivation patterns in monozygotic and dizygotic female twins.
abstract: We have tested the hypothesis that contrasting X-inactivation patterns could be a trigger for monozygotic twinning in females. X-inactivation patterns were studied in umbilical cord tissue in 43 monozygotic twin pairs and 24 dizygotic twin pairs. Very skewed or non-random X-inactivation patterns were observed in both twins in six of the monozygotic twin pairs and in one of the dizygotic twin pairs. Contrasting X-inactivation patterns occurred in only one of the six monozygotic twin pairs. This does not support the original hypothesis. There is a trend to extreme skewing of X-inactivation pattern occurring more frequently in monozygotic twins.
authors: Department of Human Genetics, University of Newcastle Upon Tyne, United Kingdom.
authors: J
authors: J
authors: Goodship
authors: J
authors: J
authors: Carter
authors: J
authors: J
authors: Burn
mesh_terms: D001483:Base Sequence; D015331:Cohort Studies; D019003:Deoxyribonuclease HpaII; D004303:Dosage Compensation, Genetic; D005260:Female; D006801:Humans; D008745:Methylation; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D011446:Prospective Studies; D011944:Receptors, Androgen / Q000235:genetics; D018911:Trinucleotide Repeats; D014429:Twins, Dizygotic / Q000235:genetics; D014430:Twins, Monozygotic / Q000235:genetics*
chemical_list: D011944:Receptors, Androgen; D019003:Deoxyribonuclease HpaII