Single nucleotide polymorphism and expression studies of the interferon gamma gene and its role against Haemonchus contortus in Garole and Sahabadi sheep

Objective: To evaluate the role of interferon gamma (IFN-γ) gene in Haemonchus contortus (H.\udcontortus) resistant in Garole/Sahabadi breed of sheep.\udMethods: Five Garole sheep (Group I) consistently showing low egg per gram in faeces (≤ 150)\udand another five Garole sheep(Group II) which had high egg per gram (≥ 500) were challenged\udwith third-stage (L3) H. contortus larvae with 500 larvae/kg body weight. Five Sahabadi sheep\ud(Group III) which were known to be susceptible to H. contortus were also fed with the same\uddose. Blood was collected from each group at different date of infection, viz. 0 day, 7 days and\ud14 days of post infection. The ovine IFN-γ was partially isolated and sequenced including intron\udand exon regions from six Garole sheep and three Sahabadi sheep prior to infection. The level of\udmessenger ribonucleic acid of IFN-γ was evaluated by means of real-time PCR at different days of\udpost infection.\udResults: In addition to one single nucleotide polymorphism at exon 3 of IFN-γ gene in three\udresistant Garole sheep, the level of mRNA in two susceptible groups was found significantly\udhigher (P ≤ 0.05) as compared to the resistant group in the present study.\udConclusions: We could clearly identify a single cytokine gene which is differentially expressed\udbetween the resistant and the susceptible animals that could be a potential target for identifying\udthe genetic marker of Haemonchus resistance. Finding of one single nucleotide polymorphism at\udexon 3 in three resistance Garole sheep might have novelty