Does adaptation to vertebrate codon usage relate to flavivirus emergence potential?

Area of Science:

• Virology
• Evolutionary Biology
• Genomics

Background:

• Viruses evolve to optimize replication and transmission through mutation, selection, and drift.
• Synonymous codon usage bias, measured by the Codon Adaptation Index (CAI), can reflect viral adaptation to host environments.
• Understanding viral adaptation is crucial for predicting zoonotic emergence and disease spread.

Purpose of the Study:

• To investigate the association between higher CAI towards a host and increased viral titers in zoonotic flaviviruses.
• To explore temporal trends in CAI for historic flaviviruses and analyze relationships within the genus.
• To demonstrate how synonymous codon changes illuminate viral evolution, epidemiology, and host adaptation.

Main Methods:

• Analysis of temporal trends in CAI for extensively sequenced zoonotic flaviviruses.
• Comparison of viral codon usage tables with those from human genes (housekeeping, antiviral), arthropod vectors, and vertebrate hosts.
• Integration of CAI analysis with existing knowledge of viral kinetics, phylodynamics, and functional genomics.

Main Results:

• Temporal CAI trends offer insights into viral evolutionary dynamics and host adaptation.
• CAI variations correlate with well-characterized historical trends across different flavivirus species and genetic diversity.
• Synonymous codon usage changes are linked to evolutionary and epidemiological patterns in flaviviruses.

Conclusions:

• CAI is a valuable tool for understanding viral adaptation and zoonotic emergence.
• Temporal CAI analysis can illuminate historical viral trends and host-pathogen interactions.
• Combining CAI with other genomic and kinetic studies enhances understanding of viral species trafficking and emergence.