Figure 2

Differential decay of parent-of-origin-specific genomic sharing in cystic fibrosis (CF)-affected sibling pairs maps a paternally imprinted locus to 7q34. a) The principle of the assay is illustrated by three concordant sibling pairs and three discordant sibling pairs. Only one parental chromosome per sibling is shown next to the siblings. Alleles at five adjacent marker loci are visualised as circles, whereby grey colour for both siblings of a pair denotes a shared chromosomal segment, and black for one and white for the other sibling of a pair denotes an unshared genomic segment. b) The data was obtained from 29 clinically concordant and 19 clinically discordant Phe508del cystic fibrosis transmembrane conductance regulator (CFTR) homozygous sibling pairs at 11 loci spanning a 38-Mb genomic area from the CFTR gene on 7q32 to 7qtel. The decay of the proportion of nonrecombined and recombined paternal chromosomes was significantly different between concordant and discordant sibling pairs, indicating a paternally imprinted CF modifier gene on 7q34. Reproduced and modified from [62] with permission from the publisher.