Polymorphism in the promoter region of the tumor necrosis factor-alpha gene in cattle herds naturally infected and uninfected with the bovine leukemia virus.

The objective of this study was to describe and compare the genetic structure (TNF-alpha -position 824) of dairy cattle herds infected and not infected with the bovine leukemia virus (BLV). The results of the present study indicate that BLV-positive herds were characterized by similar genetic structure (TNF-alpha -824A/G). The genetic equilibrium in these herds was preserved, but a tendency to increased frequency of G/G homozygotes was found. The genetic structure of the healthy herd differed considerably from that of leukemic herds.