尽管它们在区域经济上具有重要意义,并且在全球范围内受到越来越多的关注,美洲驼和羊驼的起源和进化仍然知之甚少。这里我们报告美洲驼的参考基因组,对于瓜纳科和维库尼亚(他们推定的野生祖先)来说,将这些与已发表的羊驼基因组进行比较,并对所有四个物种的七个个体进行排序,以更好地了解美洲驼和羊驼毛之间的驯化和渗入。
系统发育分析证实美洲驼是从瓜科驯化的,羊驼是从维科驯化的。羊驼基因组中的渗入(36%)比美洲驼(5%)高得多,并且可以追溯到西班牙征服的时间,大约500年前。在羊驼的X染色体上,渗入模式是最大的变数,具有53个已知在人类中具有有害X连锁表型的基因。强的全基因组渗入特征包括嗅觉受体复合物进入两个物种,高血压病抵抗进入羊驼,和羊毛/纤维性状进入美洲驼。美洲驼驯化的基因组特征包括雄性生殖特征,而在羊驼毛的特点,嗅觉相关和低氧适应特性。与人HSA4q21同态的基因渗入区域的表达分析,HSA4q21是先前在缺氧条件下与人类高血压相关的基因簇,显示了PRDM8下调作为潜在转录调节机制的先前未记录的作用,类似于先前在高海拔地区报道的缺氧诱导因子1α。
国内骆驼科基因组中前所未有的渗入特征可能反映了农业征服后的变化和传统管理实践的崩溃。
Despite their regional economic importance and being increasingly reared globally, the origins and evolution of the
llama and alpaca remain poorly understood. Here we report reference genomes for the
llama, and for the guanaco and vicuña (their putative wild progenitors), compare these with the published alpaca genome, and resequence seven individuals of all four species to better understand domestication and introgression between the
llama and alpaca.
Phylogenomic analysis confirms that the
llama was domesticated from the guanaco and the alpaca from the vicuña. Introgression was much higher in the alpaca genome (36%) than the
llama (5%) and could be dated close to the time of the Spanish conquest, approximately 500 years ago. Introgression patterns are at their most variable on the X-chromosome of the alpaca, featuring 53 genes known to have deleterious X-linked phenotypes in humans. Strong genome-wide introgression signatures include olfactory receptor complexes into both species, hypertension resistance into alpaca, and fleece/fiber traits into llama. Genomic signatures of domestication in the llama include male reproductive traits, while in alpaca feature fleece characteristics, olfaction-related and hypoxia adaptation traits. Expression analysis of the introgressed region that is syntenic to human HSA4q21, a gene cluster previously associated with hypertension in humans under hypoxic conditions, shows a previously undocumented role for PRDM8 downregulation as a potential transcriptional regulation mechanism, analogous to that previously reported at high altitude for hypoxia-inducible factor 1α.
The unprecedented introgression signatures within both domestic camelid genomes may reflect post-conquest changes in agriculture and the breakdown of traditional management practices.