SARS-CoV-2 is a type of Betacoronaviruses responsible for COVID-19 pandemic disease, with more than 1.745 million fatalities globally as of December-2020. Genetically, it is considered the second largest genome of all RNA viruses with a 5′ cap and 3′ poly-A tail. Phylogenetic analyses of coronaviruses reveal that SARS-CoV-2 is genetically closely related to the Bat-SARS Like-Corona virus (Bat-SL-Cov) with 96% whole-genome identity. SARS-CoV-2 genome consists of 15 ORFs coded into 29 proteins. At the 5′ terminal of the genome, we have ORF1ab and ORF1a, which encode the 1ab and 1a polypeptides that are proteolytically cleaved into 16 different nonstructural proteins (NSPs). The 3′ terminal of the genome represents four structural (spike, envelope, matrix, and nucleocapsid) and nine accessory (3a, 3b, 6, 7a, 7b, 8b, 9a, 9b, and orf10) proteins. As the number of COVID-19 patients increases dramatically worldwide, there is an urgent need to find a quick and sensitive diagnostic tool for controlling the outbreak of SARS-CoV-2 in the community. Today, molecular testing methods utilizing viral genetic material (e.g., PCR) represent the crucial diagnostic tool for the SARS-CoV-2 virus despite its low sensitivity in the early stage of viral infection. This review summarizes the genome composition and genetic characterization of the SARS-CoV-2.

SARS-CoV-2 是一种导致 COVID-19 大流行病的 β 冠状病毒，截至 2020 年 12 月，全球已有超过 174.5 万人死亡。从遗传学上来说，它被认为是所有具有 5' 帽和 3' 聚 A 尾的 RNA 病毒的第二大基因组。冠状病毒的系统发育分析表明，SARS-CoV-2 在遗传上与蝙蝠 SARS 样冠状病毒 (Bat-SL-Cov) 密切相关，全基因组同一性高达 96%。SARS-CoV-2 基因组由 15 个 ORF 组成，编码为 29 种蛋白质。在基因组的 5' 末端，我们有 ORF1ab 和 ORF1a，它们编码 1ab 和 1a 多肽，这些多肽被蛋白水解切割成 16 种不同的非结构蛋白 (NSP)。基因组的 3' 末端代表四种结构蛋白（刺突蛋白、包膜蛋白、基质蛋白和核衣壳蛋白）和九种辅助蛋白（3a、3b、6、7a、7b、8b、9a、9b 和 orf10）。随着全球范围内 COVID-19 患者数量急剧增加，迫切需要找到一种快速、灵敏的诊断工具来控制社区中 SARS-CoV-2 的爆发。如今，利用病毒遗传物质的分子检测方法（例如 PCR）是 SARS-CoV-2 病毒的重要诊断工具，尽管其在病毒感染早期阶段的敏感性较低。本综述总结了 SARS-CoV-2 的基因组组成和遗传特征。