T-series phages have been model organisms for molecular biology since the 1940s. Given that these phages have been stocked, distributed, and propagated for decades across the globe, there exists the potential for genetic drift to accumulate between stocks over time. Here, we compared the temporal stability and genetic relatedness of laboratory-maintained phage stocks with a T-series collection from 1972. Only the T-even phages produced viable virions. We obtained complete genomes of these T-even phages, along with two contemporary T4 stocks. Performing comparative genomics, we found 12 and 16 nucleotide variations, respectively, in the genomes of T2 and T6, whereas there were ∼172 nucleotide variations between T4 sublines compared with the NCBI RefSeq genome. To account for the possibility of artifacts in NCBI RefSeq, we used the 1972 T4 stock as a reference and compared genetic and phenotypic variations between T4 sublines. Genomic analysis predicted nucleotide variations in genes associated with DNA metabolism and structural proteins. We did not, however, observe any differences in growth characteristics or host range between the T4 sublines. Our study highlights the potential for genetic drift between individually maintained T-series phage stocks, yet after 48 years, this has not resulted in phenotypic alterations in these important model organisms.

中文翻译：

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48 岁 T 系列噬菌体的时间稳定性和遗传多样性

自 1940 年代以来，T 系列噬菌体一直是分子生物学的模式生物。鉴于这些噬菌体已经在全球储存、分布和繁殖了几十年，随着时间的推移，存在遗传漂移在种群之间积累的可能性。在这里，我们将实验室维护的噬菌体储液的时间稳定性和遗传相关性与 1972 年的 T 系列集合进行了比较。只有 T 偶数噬菌体产生了可行的病毒体。我们获得了这些 T-even 噬菌体的完整基因组，以及两个当代 T4 种群。进行比较基因组学，我们分别在 T2 和 T6 的基因组中发现了 12 和 16 个核苷酸变异，而与 NCBI RefSeq 基因组相比，T4 亚系之间有 ~172 个核苷酸变异。为了说明 NCBI RefSeq 中出现伪影的可能性，我们使用 1972 T4 股票作为参考并比较了 T4 亚系之间的遗传和表型变异。基因组分析预测了与 DNA 代谢和结构蛋白相关的基因中的核苷酸变异。然而，我们没有观察到 T4 亚系之间生长特征或宿主范围的任何差异。我们的研究强调了单独维持的 T 系列噬菌体储液之间存在遗传漂移的潜力，但 48 年后，这并没有导致这些重要模式生物的表型改变。