Characteristics of genetic resistance to Maedi-Visna in sheep breeds raised in Russia

Abstract

Relevance. Small Ruminant Lentiviruses (SRLVs), including the Visna-Maedi Virus (VMV) in sheep, induce chronic progressive inflammation primarily targeting the nervous system, lungs, mammary glands, and joints. These viruses exhibit significant genetic variability, leading to a lack of effective therapies or vaccines at an affordable cost. Foreign research has identified breed-specific variations in genetic resistance to these pathogens, but such comparative data remain largely unexplored for Russian sheep breeds. A reliable DNA marker of genetic resistance to VMV infection is the ovine transmembrane protein 154 (TMEM154) gene. This study aimed to evaluate the allelic diversity among different Russian sheep breeds through targeted SNP within the TMEM154 gene linked to genetic resistance. Methods. The study utilized biological samples (tissues) of sheep maintained at the Ladozhsky PZ and from the biobank repository titled “Genetic Materials Bank of Domestic and Wild Animals.” To identify specific mutations correlated with resistance to VMV, fragments encompassing the target SNP (OAR17_5388531) within the TMEM154 gene were amplified via RT-PCR. Results. Analysis of TMEM154 polymorphisms uncovered two distinct alleles (C and T) along with their corresponding genotypes: TT, CT, and CC. Genotype distributions associated with resistance to the Visna-Maedi virus across eighteen diverse Russian sheep breeds have been documented.