RT Journal Article SR Electronic T1 Polar Overdominance at the Ovine callipyge Locus JF Science JO Science FD American Association for the Advancement of Science SP 236 OP 238 DO 10.1126/science.273.5272.236 VO 273 IS 5272 A1 Cockett, Noelle E. A1 Jackson, Sam P. A1 Shay, Tracy L. A1 Farnir, Frédéric A1 Berghmans, Stéphane A1 Snowder, Gary D. A1 Nielsen, Dahlia M. A1 Georges, Michel YR 1996 UL http://science.sciencemag.org/content/273/5272/236.abstract AB An inheritable muscular hypertrophy was recently described in sheep and shown to be determined by the callipyge gene mapped to ovine chromosome 18. Here, the callipyge phenotype was found to be characterized by a nonmendelian inheritance pattern, referred to as polar overdominance, where only heterozygous individuals having inherited the callipyge mutation from their sire express the phenotype. The possible role of parental imprinting in the determinism of polar overdominance is envisaged.