4.22 Genomic imprinting of the Igf2 gene in mice and humans affects fetal growth. (a) The paternal Igf2 allele is active in the fetus and placenta, whereas the maternal allele is silent. (b) The human IGF2 locus is on the short arm of chromosome 11; the Igf2 locus in mice is on chromosome 7.

[Courtesy of Dr. Thomas Ried and Dr. Evelin Schrock.]