Evolutionary Patterns and Genotype-Specific Amino Acid Mutations of Tick-Borne Encephalitis Virus

Area of Science:

• Virology
• Evolutionary Biology
• Genomics

Background:

• Tick-borne encephalitis virus (TBEV) is a major cause of severe neurological disease transmitted by ticks.
• Understanding TBEV genetic diversity and evolution is crucial for public health and disease control.

Purpose of the Study:

• To comprehensively analyze the genetic diversity and evolutionary dynamics of TBEV across its known genotypes.
• To identify key amino acid mutations, including those under selection and high variability, that may impact TBEV protein function and pathogenicity.

Main Methods:

• Analysis of 263 TBEV genome sequences from the NCBI database.
• Classification of sequences into five genotypes: Baikalian, European, Far-Eastern, Himalaya, and Siberian.
• Application of entropy and positive selection analyses to identify variable and selected amino acid sites.

Main Results:

• TBEV sequences showed significant nucleotide and amino acid similarity across five genotypes with no extensive recombination.
• Entropy analysis revealed genotype-specific variable sites, with the Siberian genotype showing the highest number (n=13).
• Positive selection analysis identified several sites under selection, particularly in European, Far-Eastern, and Siberian genotypes. A total of 37 key amino acid positions were identified, mainly on viral protein surfaces.

Conclusions:

• This study provides the first comprehensive landscape of TBEV mutational variations across genotypes.
• Identified key amino acid positions may play a critical role in TBEV biology, pathogenicity, and adaptation.
• These findings offer valuable insights for future research into TBEV characteristics and the development of control strategies.