Horns are cranial appendages, which are unique in ruminants. Cattle (Bos taurus) and sheep (Ovis aries) cranial appendages exhibit various forms of morphology, including wild-type two-horn phenotype, polled phenotype and scur phenotype. These animals provide an ideal model for studies on the underlying relationship between quality and quantitative traits of cattle and sheep horn and the molecular mechanisms of horn phenotype as a polygenic regulation for quality traits. In recent years, some research progresses of cattle and sheep horns are successively reported, which helps us better understand the evolutionary origin of new organ, the effects of natural selection, sex selection and artificial selection on horn phenotypes. In this review, we introduce in details the recent advances on the research of horn traits in cattle and sheep, and summarize the genetic mapping of multi-horned phenotypes, the genetic mapping of polled locus, and studies on scur phenotype. Moreover, we discuss potential problems in such research, thereby providing a reference for investigation on the genetic mechanisms of horn traits in ruminants.
角属于动物颅骨附属物,为反刍动物所特有。牛(Bos taurus)、绵羊(Ovis aries)角的表型包括野生型两角表型、人工驯化的无角表型、畸形角等多种。牛和绵羊是阐明角的质量性状和数量性状之间的关系以及质量性状的多基因调控机制等方面的理想动物模型。近年来,对角性状研究不断深入,在阐明新器官起源进化、自然选择、性别选择和人工选择对角表型的影响等方面取得了一系列进展。本文详细介绍了角的研究概况、多角表型遗传定位、无角位点基因遗传定位和畸形角等,并对目前牛和绵羊角的遗传机制及存在的问题进行了分析,以期为反刍动物角性状和其他特异性性状遗传机制研究提供参考。.
Keywords: cranial appendages; genetic mechanism; horn trait; multi-horned phenotype; polled phenotype; sheep.