Candidate genes for tick resistance in cattle: a systematic review combining post-GWAS analyses with sequencing data

<i>Rhipicephalus microplus</i> causes huge losses in cattle. Host genetic background greatly affects the immune efficiency in resistance or susceptibility to tick infestation, which is one of the many factors that play a role on that trait. We performed a systematic review of genome-wide association studies (GWAS) for tick resistance in cattle resulting in 1353 candidate genes for post-GWAS analyses. From those, genes showing possible structural variants from the bovine genome were classified by the Variant Effect Predictor from Ensembl. Ninety-two candidate genes showed potential structural variants in 5′ UTR and coding region and were used for functional annotation. Enriched biological processes (e.g. regulation of eosinophil chemotaxis, RIG-I signalling pathway and monocyte differentiation) and candidate genes (e.g. <i>DAPK2, PUM1, ACIN1, INPP5D</i>) linked with immune system function were identified and thus associated with tick resistance. Besides, gene-transcription factors (TFs) networks were obtained from TFs associated with immune system (<i>FOXO3, PPARG, STAT3, NFKB1, GATA3 and ARNT</i>) and the candidate genes associated with tick resistance in cattle highlighted (e.g. <i>OR4L1, PNP, LRRIQ1, GIMAP8, MYO6, MEP1A and LRFN2</i>). Thus, promising candidate genes with a possible functional role for tick resistance in cattle are presented for further <i>in vitro</i> and/or <i>in vivo</i> analyses.