Different sheep breeds have evolved after initial domestication, generating various tail phenotypic patterns. The phenotypic diversity of sheep tail patterns offers ideal materials for comparative analysis of its genetic basis. Evolutionary biologists, animal geneticists, breeders, and producers have been curious to clearly understand the underlying genetics behind phenotypic differences in sheep tails. Understanding the causal gene(s) and mutation(s) underlying these differences will help probe an evolutionary riddle, improve animal production performance, promote animal welfare, and provide lessons that help comprehend human diseases related to fat deposition (i.e., obesity). Historically, fat tails have served as an adaptive response to aridification and climate change. However, the fat tail is currently associated with compromised mating and animal locomotion, fat distribution in the animal body, increased raising costs, reduced consumer preference, and other animal welfare issues such as tail docking. The developing genomic approaches provide unprecedented opportunities to determine causal variants underlying phenotypic differences among populations. In the last decade, researchers have performed several genomic investigations to assess the genomic causality underlying phenotypic variations in sheep tails. Various genes have been suggested with the prominence of several potentially significant causatives, including the BMP2 and PDGFD genes associated with the fat tail phenotype and the TBXT gene linked with the caudal vertebrae number and tail length. Although the potential genes related to sheep tail characteristics have been revealed, the causal variant(s) and mutation(s) of these high-ranking candidate genes are still elusive and need further investigation. The review discusses the potential genes, sheds light on a knowledge gap, and provides possible investigative approaches that could help determine the specific genomic causatives of sheep tail patterns. Besides, characterizing and revealing the genetic determinism of sheep tails will help solve issues compromising sheep breeding and welfare in the future.

中文翻译：

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揭示绵羊尾巴图案遗传结构的趋势：有前途的基因和研究途径

不同的绵羊品种在最初驯化后进化，产生各种尾部表型模式。羊尾巴模式的表型多样性为其遗传基础的比较分析提供了理想的材料。进化生物学家、动物遗传学家、饲养员和生产者一直好奇地想清楚地了解羊尾巴表型差异背后的潜在遗传学。了解这些差异背后的因果基因和突变将有助于探索进化之谜，提高动物生产性能，促进动物福利，并提供有助于理解与脂肪沉积相关的人类疾病（即肥胖）的经验教训。从历史上看，肥尾是对干旱化和气候变化的适应性反应。然而，肥尾目前与交配和动物运动受损、动物体内脂肪分布、饲养成本增加、消费者偏好降低以及其他动物福利问题（如断尾）有关。发展中的基因组方法为确定人群间表型差异的因果变异提供了前所未有的机会。在过去十年中，研究人员进行了多项基因组研究，以评估羊尾巴表型变异背后的基因组因果关系。已经提出了多种基因，其中包括几个潜在的重要致病因素，包括 发展中的基因组方法为确定人群间表型差异的因果变异提供了前所未有的机会。在过去十年中，研究人员进行了多项基因组研究，以评估羊尾巴表型变异背后的基因组因果关系。已经提出了多种基因，其中包括几个潜在的重要致病因素，包括 发展中的基因组方法为确定人群间表型差异的因果变异提供了前所未有的机会。在过去十年中，研究人员进行了多项基因组研究，以评估羊尾巴表型变异背后的基因组因果关系。已经提出了多种基因，其中包括几个潜在的重要致病因素，包括BMP2和PDGFD基因与肥尾表型相关，TBXT基因与尾椎骨数量和尾长相关。尽管与羊尾巴特征相关的潜在基因已经被揭示，但这些高等级候选基因的因果变异和突变仍然难以捉摸，需要进一步研究。该评论讨论了潜在的基因，揭示了知识差距，并提供了可能的调查方法，可以帮助确定羊尾巴模式的特定基因组原因。此外，表征和揭示绵羊尾巴的遗传决定性将有助于解决未来影响绵羊育种和福利的问题。