The tables that are used to rank the mutations were created through literature research.
An overview of the papers they are derived from can be found below. The corresponding papers for every single mutation can be found in the source column of the table.
Those are mutations that have been identified previously in the literature as changing the potential of the virus.
Burke, David & Smith, Derek. (2014). A Recommended Numbering Scheme for Influenza A HA Subtypes. PloS one. 9. e112302. 10.1371/journal.pone.0112302.
Ciblak, Meral & Hasoksuz, Mustafa & Kanturvardar, Melis & Asar, Serkan & Badur, Selim. (2013). Molecular and serological investigations of the Influenza A(H1N1) 2009 pandemic virus in Turkey. Medical microbiology and immunology. 202. 10.1007/s00430-013-0291-4.
Guarnaccia, Teagan & Carolan, Louise & Maurer-Stroh, Sebastian & Lee, Raphael Tze Chuen & Job, Emma & Reading, Patrick & Petrie, Stephen & Mccaw, James & Mcvernon, Jodie & Hurt, Aeron & Kelso, Anne & Mosse, Jennifer & Barr, Ian & Laurie, Karen. (2013). Antigenic Drift of the Pandemic 2009 A(H1N1) Influenza Virus in a Ferret Model. PLoS pathogens. 9. e1003354. 10.1371/journal.ppat.1003354.
Adam, Dillon & Scotch, Matthew & Macintyre, Chandini. (2019). Phylodynamics of Influenza A/H1N1pdm09 in India Reveals Circulation Patterns and Increased Selection for Clade 6b Residues and Other High Mortality Mutants. Viruses. 11. 791. 10.3390/v11090791.
Goka, Edward & Vallely, Pamela & Mutton, Ken & Klapper, P. (2014). Mutations associated with severity of the pandemic influenza A(H1N1)pdm09 in humans: a systematic review and meta-analysis of epidemiological evidence. Archives of virology. 159. 10.1007/s00705-014-2179-z.
Venter, Marietjie & Naidoo, Dhamari & Pretorius, Marthi & Buys, Amelia & McAnerney, Johanna & Blumberg, Lucille & Madhi, Shabir & Cohen, Cheryl & Schoub, Barry. (2012). Evolutionary Dynamics of 2009 Pandemic Influenza A Virus Subtype H1N1 in South Africa During 2009-2010. The Journal of infectious diseases. 206 Suppl 1. S166-72. 10.1093/infdis/jis539.
Graham, Morag & Liang, Binhua & Domselaar, Gary & Bastien, Nathalie & Beaudoin, Carole & Tyler, Shaun & Kaplen, Brynn & Landry, Erika & Li, Yan. (2011). Nationwide Molecular Surveillance of Pandemic H1N1 Influenza A Virus Genomes: Canada, 2009. PloS one. 6. e16087. 10.1371/journal.pone.0016087.
Glinsky, Gennadi. (2010). Genomic analysis of pandemic (H1N1) 2009 reveals association of increasing disease severity with emergence of novel hemagglutinin mutations. Cell cycle (Georgetown, Tex.). 9. 958-70. 10.4161/cc.9.5.10913.
Barrero, P. & Viegas, Mariana & Valinotto, Laura & Mistchenko, Alicia. (2011). Genetic and Phylogenetic Analyses of Influenza A H1N1pdm Virus in Buenos Aires, Argentina. Journal of virology. 85. 1058-66. 10.1128/JVI.00936-10.
Brown, Sook & Tseng, Yeu-Yang & Aziz, Ammar & Baz, Mariana & Barr, Ian. (2022). Characterization of influenza B viruses with reduced susceptibility to influenza neuraminidase inhibitors. Antiviral Research. 200. 105280. 10.1016/j.antiviral.2022.105280.
Zaraket, Hassan & Hurt, Aeron & Clinch, Barry & Barr, Ian & Lee, Nelson. (2021). Burden of influenza B virus infection and considerations for clinical management. Antiviral Research. 185. 104970. 10.1016/j.antiviral.2020.104970.
Graham, Morag & Liang, Binhua & Domselaar, Gary & Bastien, Nathalie & Beaudoin, Carole & Tyler, Shaun & Kaplen, Brynn & Landry, Erika & Li, Yan. (2011). Nationwide Molecular Surveillance of Pandemic H1N1 Influenza A Virus Genomes: Canada, 2009. PloS one. 6. e16087. 10.1371/journal.pone.0016087.
Barrero, P. & Viegas, Mariana & Valinotto, Laura & Mistchenko, Alicia. (2011). Genetic and Phylogenetic Analyses of Influenza A H1N1pdm Virus in Buenos Aires, Argentina. Journal of virology. 85. 1058-66. 10.1128/JVI.00936-10.
Those are important regions of the gene like for example Antigenic sites or Receptor-binding sites.
Manabu Igarashi et al. “Predicting the Antigenic Structure of the Pandemic (H1N1) 2009 Influenza Virus Hemagglutinin”. In: PloS one 5 (Jan. 2010), e8553. doi: 10.1371/journal.pone.0008553.
Sean Liu et al. “Antigenic sites in influenza H1 hemagglutinin display species-specific immunodominance”. In: Journal of Clinical Investigation 128 (Sept. 2018). doi: 10.1172/JCI122895.
Mir Muneer Ahmad et al. “Genetic diversity of HA1 domain of hemagglutinin gene of pandemic influenza H1N1pdm09 viruses in New Delhi, India”. In: Journal of medical virology 84 (Mar. 2012), pp. 386–93. doi: 10.1002/jmv.23205.
Nongluk Sriwilaijaroen and Yasuo Suzuki. “Molecular basis of the structure and function of H1 hemagglutinin of influenza virus”. In: Proceedings of the Japan Academy. Series B, Physical and biological sciences 88 (June 2012), pp. 226–49. doi: 10.2183/pjab.88.226.
Hua Yang, Paul Carney, and James Stevens. “Structure and Receptor binding properties of a pandemic H1N1 virus hemagglutinin”. In: PLoS Currents 2 (Mar. 2010). doi: 10.1371/currents.RRN1152.
Edward Goka et al. “Mutations associated with severity of the pandemic influenza A(H1N1)pdm09 in humans: a systematic review and meta-analysis of epidemiological evidence”. In: Archives of virology 159 (July 2014). doi: 10.1007/s00705-014-2179-z.
David Burke and Derek Smith. “A Recommended Numbering Scheme for Influenza A HA Subtypes”. In: PloS one 9 (Nov. 2014), e112302. doi: 10.1371/journal.pone.0112302