The order Crassvirales, which includes the prototypical crAssphage (p-crAssphage), is predominantly associated with humans, rendering it the most abundant and widely distributed group of DNA phages in the human gut. The reported human specificity and wide global distribution of p-crAssphage makes it a promising human fecal marker. However, the specificity for the human gut as well as the geographical distribution around the globe of other members of the order Crassvirales remains unknown. To determine this, a recruitment analysis using 91 complete, non-redundant genomes of crAss-like phages in human and animal viromes revealed that only 13 crAss-like phages among the 91 phages analyzed were highly specific to humans, and p-crAssphage was not in this group. Investigations to elucidate whether any characteristic of the phages was responsible for their prevalence in humans showed that the 13 human crAss-like phages do not share a core genome. Phylogenomic analysis placed them in three independent families, indicating that within the Crassvirales group, human specificity is likely not a feature of a common ancestor but rather was introduced on separate/independent occasions in their evolutionary history. The 13 human crAss-like phages showed variable geographical distribution across human metagenomes worldwide, with some being more prevalent in certain countries than in others, but none being universally identified. The varied geographical distribution and the absence of a phylogenetic relationship among the human crAss-like phages are attributed to the emergence and dissemination of their bacterial host, the symbiotic human strains of Bacteroides, across various human populations occupying diverse ecological niches worldwide.

中文翻译：

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募集完整的 crAs 样噬菌体基因组显示它们存在于鸡病毒组中，人类特异性噬菌体很少，并且缺乏普遍检测


Crassvirales 目，包括原型 crAssphage （p-crAssphage），主要与人类相关，使其成为人类肠道中最丰富和分布最广泛的 DNA 噬菌体组。据报道的人类特异性和 p-crAssphage 的广泛全球分布使其成为一种很有前途的人类粪便标志物。然而，Crassvirales 目其他成员对人类肠道的特异性以及全球地理分布仍然未知。为了确定这一点，在人类和动物病毒组中使用 91 个完整的、非冗余的 crAss 样噬菌体基因组进行的募集分析表明，在分析的 91 个噬菌体中，只有 13 个 crAss 样噬菌体对人类具有高度特异性，而 p-crAssphage 不属于该组。阐明噬菌体的任何特征是否导致它们在人类中普遍存在的调查表明，13 种人类 crAs 样噬菌体不共享核心基因组。系统发育分析将它们分为三个独立的科，表明在 Crassvirales 组中，人类特异性可能不是共同祖先的特征，而是在它们进化历史中单独/独立的情况下引入的。13 种人类 crAs 样噬菌体在全球人类宏基因组中显示出不同的地理分布，其中一些在某些国家比在其他国家更普遍，但没有一个被普遍识别。人类 crAs 样噬菌体之间不同的地理分布和系统发育关系的缺失归因于它们的细菌宿主（拟杆菌的共生人类菌株）的出现和传播，在占据全球不同生态位的不同人类群体中。