| Institution: | 1. Department of Genetics, Faculty of Agriculture, Zagazig University, Zagazig 44511, Egypt;2. State Key Laboratory of Animal Genetics Breeding & Reproduction, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, PR China;3. Department of Zoology, Shah Abdul Latif University Khairpur, Sindh, Pakistan;4. Department of Biology, Faculty of Science, University of Hail, Hail 81411, Saudi Arabia;5. Department of Clinical Microbiology, Immunology, Department of Radiation Sciences, Oncology, Umeå University, SE-90185 Umeå, Sweden;6. Biology Department, College of Science, Jouf University, Sakaka 2014, Saudi Arabia;7. Department of Biochemistry, Faculty of Agriculture, Zagazig University, Zagazig 44511, Egypt;8. Biology Department, College of Science and Humanities, Prince Sattam bin Abdulaziz University, 83, Al-Kharj 11940, Saudi Arabia;9. Department of Plant Pathology, Faculty of Agriculture, Zagazig University, Zagazig 44511, Egypt;10. Biology Department, College of Science, King Khalid University, 61413 Abha, Saudi Arabia;11. Biology Department, Faculty of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia;12. Department of Theriogenology, Faculty of Veterinary Medicine, South Valley University, 83523 Qena, Egypt;13. Department of Animal Production, College of Food and Agriculture Sciences, King Saud University, PO Box 2460, Riyadh 11451, Saudi Arabia;14. Department of Theriogenology, Faculty of Veterinary Medicine, Zagazig University, Sharkia 44519, Egypt;15. Department of Agricultural Microbiology, Faculty of Agriculture, Zagazig University, Zagazig 44511, Egypt |
| Abstract: | The emergence of coronavirus disease 2019 (COVID-19) pandemic in Wuhan city, China at the end of 2019 made it urgent to identify the origin of the causal pathogen and its molecular evolution, to appropriately design an effective vaccine. This study analyzes the evolutionary background of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 or SARS-2) in accordance with its close relative SARS-CoV (SARS-1), which was emerged in 2002. A comparative genomic and proteomic study was conducted on SARS-2, SARS-1, and Middle East respiratory syndrome coronavirus (MERS), which was emerged in 2012. In silico analysis inferred the genetic variability among the tested viruses. The SARS-1 genome harbored 11 genes encoding 12 proteins, while SARS-2 genome contained only 10 genes encoding for 10 proteins. MERS genome contained 11 genes encoding 11 proteins. The analysis also revealed a slight variation in the whole genome size of SARS-2 comparing to its siblings resulting from sequential insertions and deletions (indels) throughout the viral genome particularly ORF1AB, spike, ORF10 and ORF8. The effective indels were observed in the gene encoding the spike protein that is responsible for viral attachment to the angiotensin-converting enzyme 2 (ACE2) cell receptor and initiating infection. These indels are responsible for the newly emerging COVID-19 variants αCoV, βCoV, γCoV and δCoV. Nowadays, few effective COVID-19 vaccines developed based on spike (S) glycoprotein were approved and become available worldwide. Currently available vaccines can relatively prevent the spread of COVID-19 and suppress the disease. The traditional (killed or attenuated virus vaccine and antibody-based vaccine) and innovated vaccine production technologies (RNA- and DNA-based vaccines and viral vectors) are summarized in this review. We finally highlight the most common questions related to COVID-19 disease and the benefits of getting vaccinated. |
