MITOCHONDRIAL PEPCK - A HIGHLY POLYMORPHIC GENE WITH ALLELES CO-SELECTED WITH MAREKS-DISEASE RESISTANCE IN CHICKENS

The gene coding for the mitochondrial phosphoenolpyruvate carboxykinas e (PEPCK-M), a pivotal component in gluconeogenesis from lactate via t he Cori cycle, was highly polymorphic in strains of egg-type chickens (White Leghorn) of different origins. Based on MspI restriction fragme nt polymorphisms a total of seven alleles could be distinguished. The allele frequencies were determined in six pairs of strains derived fro m different genetic base populations. Each pair consisted of two strai ns which differed in their susceptibility to Marek's disease (MD), a v irus-induced neoplastic disease. The frequency of the most common hapl otype (M2) was consistently higher in the susceptible strains than in the corresponding resistant strains (P < 0.05, Wilcoxon signed ranks t est), indicating that the observed differences were not due to random genetic drift. This result suggests that PEPCK-M may be a candidate ge ne which contains genetic variants affecting MD susceptibility. Variat ions in gluconeogenesis may affect the interplay between proliferation of neoplasia and host metabolism.