Genetic research conducted at The Pirbright Institute in the U.K. has revealed that goat and sheep genes for specific immune cell receptors are extremely diverse and differ from other livestock relatives.
According to the announcement, the findings will help scientists understand how genetic characteristics can alter an animal’s natural ability to fight infection and potentially inform breeding of disease-resistant animals.
The Pirbright team investigated the genome sequences of goats and sheep to better understand how natural killer (NK) cells recognize when other cells are infected by invasive viruses or other microbes, the institute said. NK cells have receptor proteins on their surface that detect infected cells and initiate their destruction to halt the spread of microorganisms.
The study, published in Frontiers in Immunology, is the first to analyze killer-cell immunoglobulin-like receptor (KIR) genes in goats and sheep, Pirbright said.
According to the researchers, these highly variable genes — similar versions of which can be found in humans — are some of the most rapidly evolving areas of the genome. This is due to the need to generate receptors that can detect the frequent mutations microbes make to avoid the immune cells, they explained.
The high levels of repetitive sequence in the KIR genes and surrounding DNA make accurately characterizing them extremely difficult, Pirbright said. However, using advanced sequencing technology, the researchers were able to pinpoint three functional KIR gene subgroups shared by sheep and goats, only one of which is shared between goats and cattle. This variation among species reflects the rapid changes KIR genes must go through in order to detect cells infected by pathogens that are specific to each animal, the researchers noted.
“Obtaining accurate KIR gene sequences helps us understand how these NK receptors are involved in goat immune responses to intracellular infections,” said Dr. John Schwartz, first author of the study at Pirbright. “This knowledge will help inform livestock genotyping platforms for the purpose of breeding healthier animals that have improved natural resistance to specific pathogens.”