Background: Horns, as a significant characteristic of ruminants, play an important role in their bodily structures and functions. A comprehensive analysis of the origin and evolution of horns will deepen our understanding of the biological mechanisms driving horn development. Relaxin/Insulin-like Family Peptide Receptor 2 (RXFP2) is a candidate gene associated with the development and morphology of sheep horns and a significant selection signal related to horn traits has been detected in the RXFP2 gene on chromosome 10. 
 
Methods: To further explore the regulatory effects of RXFP2 on horn presence or absence in Oula sheep, an important local meat breed in Qinghai, this study employed multiplex PCR to detect the selection signal of the RXFP2 gene in the genomes of 50 horned Oula sheep (wild type) and 50 hornless Oula sheep (bred within the breed). 
 
Result: We identified three single nucleotide polymorphisms (SNPs) associated with the horned phenotype in Oula sheep: one synonymous mutation in exon 14 (29512087:T&gt;C) and two non-synonymous mutations in exon 17 (29505054:C&gt;T and 29505096:C&gt;T). This study provides additional evidence for the association between RXFP2 coding-region variants and horn phenotype in Oula sheep and offers potential molecular markers for future breeding applications after validation in larger and independent populations. 
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Multiplex PCR-based Detection of SNPs in RXFP2 Associated with the Oula Sheep (Tibetan Sheep, Ovis Aries) Horn Phenotype