Allelic-specific expression of IGF2 and H19 in human placenta.

aDNA methylation levels on maternal and paternal (M/P) alleles (a ratio of zero corresponds to exclusive methylation of the MluI site on the paternal allele, while a ratio of one signifies methylation of this site on an equal number of maternal and paternal alleles).
bThe threshold for scoring loss of imprinting for IGF2 was a ratio of less than 3∶1 between the more-abundant and less abundant alleles [32].