背景:羊驼是一种南美的骆驼科动物,可能来自两个野生骆驼科动物的驯化,维库尼亚和瓜纳科。描述了羊驼的两种表型,被称为huacaya和suri。Huacaya羊毛的特点是紧凑,软,和高度卷曲的纤维,虽然苏里羊毛更长,直,卷曲较少,还有光泽.决定这些表型的基因变异仍然未知,尽管以前的研究表明suri的显性遗传。基于此,本研究的目的是通过全基因组测序(WGS)分析鉴定确定羊驼皮衣表型的基因变异.
结果:使用的样本包括两个测试杂交羊驼家族,suri×huacaya,产生了两个后代,一个具有suri表型,一个具有huacaya表型。通过添加来自六个vicugnas和六个guanacos的WGS数据来扩展分析的样品;这是因为我们假设在这些野生物种中不存在与suri表型相关的基因变体。与suri表型的基因变异分离分析,加上对野生物种中存在的基因变异的过滤,揭示了TRPV3(瞬时受体电位阳离子通道亚家族V成员3)中所有suri样品中都存在提前终止密码子(PTC),一种已知与头发生长和循环有关的基因,热感觉,几个物种的耐寒性和适应性。TRPV3的突变先前与毛发结构的改变有关,导致小鼠的毛管和毛干形成受损。TRPV3中的这种PTC,由于G>T取代(p。Glu475*),导致规范翻译蛋白损失290个氨基酸,可能导致生理功能紊乱。
结论:目前的结果表明,苏里表型可能来自TRPV3基因变异,这可能解释了苏里的一些特征,例如与huacaya相比,其较长的毛发纤维和较低的角质层鳞片数量。
BACKGROUND: Alpaca is a domestic South American camelid probably arising from the domestication of two wild camelids, the vicugna and the guanaco. Two phenotypes are described for alpaca, known as huacaya and suri. Huacaya fleece is characterized by compact, soft, and highly crimped fibers, while suri fleece is longer, straight, less crimped, and lustrous. The gene variants determining these phenotypes are still unknown, although previous studies suggested a dominant inheritance of the suri. Based on that, the aim of this study was the identification of the gene variants determining alpaca coat phenotypes through whole genome sequencing (WGS) analysis.
RESULTS: The sample used includes two test-cross alpaca families, suri × huacaya, which produced two offspring, one with the suri phenotype and one with the huacaya phenotype. The analyzed sample was expanded through the addition of WGS data from six vicugnas and six guanacos; this because we assumed the absence of the gene variants linked to the suri phenotype in these wild species. The analysis of gene variant segregation with the suri phenotype, coupled with the filtering of gene variants present in the wild species, disclosed the presence in all the suri samples of a premature termination codon (PTC) in TRPV3 (transient receptor potential cation channel subfamily V member 3), a gene known to be involved in hair growth and cycling, thermal sensation, cold tolerance and adaptation in several species. Mutations in TRPV3 were previously associated with the alteration of hair structure leading to an impaired formation of the hair canal and the hair shaft in mouse. This PTC in TRPV3, due to a G > T substitution (p.Glu475*), results in a loss of 290 amino acids from the canonical translated protein, plausibly leading to a physiological dysfunction.
CONCLUSIONS: The present results suggest that the suri phenotype may arise from a TRPV3 gene variant which may explain some of the suri features such as its longer hair fibre with lower number of cuticular scales compared to huacaya.