Ann. Méd. Vét., 2006, 150 (1), pp 64-70 The callipyge phenomenon : cis effects, trans effects, and polar overdominanceDAVIS E., GEORGES M., CHARLIER C.Abstract :
The callipyge phenotype is a postnatal muscular hypertrophy characterized in sheep.
Callipyge follows an unusual,
non-Mendelian mode of inheritance,
referred to as “polar overdominance” in which only heterozygous animals having
received the mutation from their sire display the phenotype. The callipyge (CLPG) locus maps to the DLK1-GTL2 imprinted domain and the causal mutation
is a single nucleotide polymorphism(SNP) which we postulate to disrupt the binding site of a skeletal muscle specific, longrange regulatory element. Here, we overview our current understanding of the molecular mechanisms underlying polar overdominance and provide evidence that this genetic phenomenon is the result of a combination of the cis effect of the callipyge mutation with the trans interaction of reciprocally imprinted gene products. Get the PDF Contact person : michel.georges@ulg.ac.be |