Seattle Children's Research Institute, Seattle, WA, USA; Schools of Medicine and Public Health, University of Washington, Seattle, WA, USA.
Africa Health Research Institute, University of KwaZulu-Natal, Durban, South Africa.
Virus Res. 2021 Jan 15;292:198219. doi: 10.1016/j.virusres.2020.198219. Epub 2020 Nov 1.
crAssphages are a broad group of diverse bacteriophages in the order Caudovirales that have been found to be highly abundant in the human gastrointestinal tract. Despite their high prevalence, we have an incomplete understanding of how crAssphages shape and respond to ecological and evolutionary dynamics in the gut. Here, we report genomes of crAssphages from feces of one South African woman and three infants. Across the complete genome sequences of the South African crAssphages described here, we identify particularly elevated positive selection in RNA polymerase and phage tail protein encoding genes, contrasted against purifying selection, genome-wide. We further validate these findings against a crAssphage genome from previous studies. Together, our results suggest hotspots of selection within crAssphage RNA polymerase and phage tail protein encoding genes are potentially mediated by interactions between crAssphages and their bacterial partners.
粪便噬菌体是一种广泛存在于长尾病毒目（Caudovirales）的多样性噬菌体，大量存在于人类胃肠道中。尽管它们的流行程度很高，但我们对粪便噬菌体如何影响和响应肠道中的生态和进化动态仍知之甚少。在这里，我们报告了一位南非女性和三位婴儿粪便中粪便噬菌体的基因组。在描述的南非粪便噬菌体的完整基因组序列中，我们发现 RNA 聚合酶和噬菌体尾部蛋白编码基因的正选择特别高，而与全基因组的纯化选择形成对比。我们还针对之前研究中的粪便噬菌体基因组对这些发现进行了验证。总的来说，我们的结果表明，粪便噬菌体 RNA 聚合酶和噬菌体尾部蛋白编码基因中的选择热点可能是由粪便噬菌体与其细菌伙伴之间的相互作用介导的。
